Germplasm by AVRDC

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A compilation of lecture materials of a training course held in BART, joydebpur, Gazipur, Bangladesh 4-6 May 1992

compiled by

Chadha, A. .K. Amzad Hossain, and S. M. Mono war Hossain

organized by AVRDC, BARI, and BARC and funded by USAID Agricultural Research Project II Supplement

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Germplasm collection, evaluation,

©1993. Asian Vegetable Research and Development Center P.O. Box 205, Taipei 10099 Suggested citation: AVRDC. 1993. Germplasm collection, evaluation, documentation, and conservation. (A compilation of lecture materials of a training course held in BARI, Joydebpur, Gazipur, Bangladesh, 4–6 May 1992). Asian Vegetable Research and Development Center. Shanhua, Tainan, Taiwan. Publication no. 93-398, 95 pp. The training on " Germplasm collection, evaluation, documentation, and conservation" was a joint effort of AVRDC, the Bangladesh Agricultural Research Council (BARC), and the Bangladesh Agricultural Research Institute (BARI), and funded by the United States Agency for International Development through its Agricultural Research Project II Supplement.

ISBN: 92-9058-069-0

Editor: Katherine Lopez

documentation, and conservation

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Contents

An introduction: germplasm system of AVRDC

5

L.M. Engle
Introduction to concepts of germplasm conservation 11

L.M. Engle
Genetic resources and their role in horticultural crop improvement 18

Obaidul Islam
Germplasm collecting strategies 23

L.M. Engle
Genetic diversity of local vegetables 37

S.M. Monowar Hossain and M. Mozammal Hogue
Characterization of germplasm 41

L. M. Engle
Techniques of handling and storing vegetable seeds 62

M.L. Chadha
Germplasm evaluation and utilization 69

Jean M. Poulos
Seed processing and preservation 75

L.M. Engle
Evaluation and conservation of germplasm of important fruit crops 80

A.K.M. Amzad Hossain
Appendices 91

documentation, and conservation

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An Introduction: Germplasm System

L.M. Engle Geneticist and Head Genetic Resources and Seed Unit, AVRDC Shanhua, Tainan, Taiwan, ROC Introduction

In 1971, the Asian Vegetable Research and Development Center, an autonomous, philanthropic, nonprofit and development organization, was established to promote the production, marketing, and utilization of vegetables in the Asian region with the ultimate purpose of improving the health condition of Asian people through an adequate supply of essential nutrients. A Memorandum of Understanding was signed on 22 May 1971 to record the official establishment of the Center and the active participation by countries interested in its cause. In 1975, a Seed Laboratory Unit was established and in 1985, a Genetic Resources and Seed Unit (GRSU) Laboratory was designed and constructed. Objectives of GRSU AVRDC's mission is "to enhance the nutritional well-being and raise the incomes of poor people in the rural and urban areas of developing countries, through improved methods of vegetable production, marketing and distribution, which take into account the need to preserve the quality of the environment." To attain this goal AVRDC has identified three broad categories of activities, one of which is the "conservation of vegetable genetic resources and their use for crop improvement". This activity is the major responsibility of GRSU.

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Germplasm collection, evaluation,

GRSU has the following objectives: • to build up base and active collections of vegetable species popular in the tropics; • to promote the utilization of the collections through evaluation and comprehensive documentation; • to strengthen AVRDC's cooperation within the international network of genebanks; • to promote the use of good quality vegetable seeds in the tropics; and • to ensure that incoming and outgoing seed samples are free of pests and diseases. The AVRDC vegetable germplasm collection The AVRDC collection represents a unique and invaluable regional and world resources of -germplasm. It has assembled one of the largest vegetable genebanks and has been recognized by the International Board for Plant Genetic Resources (IBPGR) as being responsible for the world base collection of mungbean and the global duplicate collection of pepper. The collection was assembled primarily because of the need for germplasm in crop improvement programs of both the Center and those of the NARS (national agricultural research systems). The AVRDC collection is therefore utilization-oriented. Secondly, the collection is conserved for future needs and thirdly, because there is a need to conserve endangered species. The long-term objective of AVRDC is to assemble a comprehensive collection of its principal crops, as well as the major vegetable crops in each of the regions including indigenous species. Table 1 shows the current status of AVRDC's vegetable germplasm collection.

Table 1. The AVRDC-GRSU vegetable germplasm collection (March 1992)
Crop Principal crops Soybean Tomato Pepper Mungbean Chinese cabbage Eggplant Allium (onion, garlic, shallot) Subtotal No. of accessions 12,672 6,390 5,930 5,741 1,502 164 120 32,519 Crop No. of accessions Nonprincipal crops Yard-long bean and cowpea Black gram Pltaseolus bean (including Lima bean) Pea Lablab bean Adzuki bean Amaranthus Melon Rice bean Others Subtotal

1,864 451 393 204 191 136 133 102 79 1,428 4,981

Total

37,500

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The vegetable germplasm collection has been assembled mainly through personal contacts, exchanges with institutions and individuals, as well as actual field collection. The materials assembled will provide a broader genetic base for vegetable breeding programs and will provide safety backups to the dangers of a limited and highly uniform gene pool. In the last two years, the number has increased as a result of collecting expeditions in Malaysia, Philippines, and Thailand as part of the JICA-supported project "Conservation, Evaluation and Utilization of Vegetable Genetic Resources — A Collaborative Network Project for Southeast Asia." Additional collecting is planned for Indonesia. The collection, at least for pepper and mungbean, is envisioned to include as wide a range of diversity as possible. Vegetable breeders and other researchers require genetically diverse materials to be able to continuously develop improved types and varieties of crops that can face the challenge of an environment that is both evolving and becoming limiting. A genetically diverse genepool is the raw material from which the plant breeder molds new varieties. The availability of specific genes in the collection determines the success of the plant breeder in fashioning a variety with specific characteristics. The more diverse a genepool is, the higher is the probability that it would contain the desirable genes. In the next 5 years, GRSU proposes to increase the number of accessions of the new principal crops of AVRDC (allium, eggplant, common cabbage), increase accessions of wild and weedy species related to the principal crops, assemble germplasm possessing special traits identified in evaluation programs and continue comprehensive collecting of vegetable germplasm in Southeast Asian countries in collaboration with the national programs and the Japanese government. Enhancing utilization of the AVRDC collection Since the collection is primarily utilization-oriented and secondarily conservationoriented, GRSU maintains a large active collection for distribution purposes. The AVRDC tomato collection has already been described as the largest and most comprehensive active collection of tomato germplasm in the world. GRSU's goal is to complement its base collection with a dynamic active collection. Requests for seed samples of materials in the collection as well as breeding lines are regularly received at AVRDC. As of 1991 289,296 seed samples have been distributed to 180 countries and territories. WithinAVRDC 164,567 seed samples have been distributed by GRSU to other research units. Most of the seeds distributed outside AVRDC are breeding lines, including sets involved in variety trials (e.g., IMN, INTHOPE, ASET, AVNET). Requests are also received for special groups of materials such as soybean with black seed coat, representatives of different species of Capsicum, Lycopersicon and Vigna and minor legumes. GRSU also fills requests for seeds of nonprincipal crops, the highest being for Amaranthus.

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Gerrnplasnn collection, evaluation,

To be able to multiply the collection in the shortest time possible, AVRDC has sought the cooperation of countries with strong genetic resources programs. Multiplication of soybean is done in collaboration with Kasetsart University, Thailand while multiplication of pepper is done in collaboration with the National Plant Genetic Resources Laboratory (NPGRL), Philippines. Newly collected materials are increased in the country of origin. To enhance utilization, evaluation data must be available. Morphoagronomic characterization is usually done routinely during multiplication for long-term storage. Mungbean has been extensively characterized and "Germplasm Catalog of Mungbean ( Vigna radiata [L.] Wilczek) and Other Vigna Species" has been published. Our priority in the next 5 years is the characterization of our other global responsibility — pepper. Characterization follows closely the IBPGR crop descriptors. Evaluation for traits of immediate importance to breeders (e.g., resistance to pests, diseases and abiotic stresses, improved quality, etc.) are done with the participation of researchers from several disciplines (e.g., entomologists, pathologists, virologists, physiologists, chemists, etc.). In this way, invaluable genepools that can be channeled into breeding programs can be identified. Conservation GRSU maintains base, active and working collections. Base collections are kept in longterm storage conditions in laminated aluminum polyethylene pouches. Active collections are kept in medium-term storage condition, while working collections are kept in shortterm storage conditions. For asexually propagated species, GRSU maintains an in vitro collection and a field genebank. For additional security, the collection is duplicated in other genebanks outside of Taiwan (e.g., USA, Japan). When the Svalbard International Seedbank becomes operational, GRSU intends to store its duplicate collection in permafrost. As part of the conservation strategy, GRSU routinely determines initial viability of materials put into long-term storage. This data is used to predict longevity of seeds in storage, schedule viability monitoring tests, and regeneration. Meeting standards of genebanks In all of its undertakings, GRSU strives to meet scientifically designed standards and recommendations set by IBPGR. GRSU has conservation facilities for the following: ®long-term storage at -10 and -20°C, frost-free ®medium-term storage at 2-5°C, 40–45% RH • short-tern storage at 15°C, 40% RH

documentation, and conservation ® tuber storage at 15°C, 80-95%RH I ®in vitro conservation room ®field genebank

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A 32-channel electronic recorder monitors the temperature and relative humidity of the cold stores. The unit has laboratory and seed conditioning rooms, seed drying, packing, germination, and preparation rooms. Slow drying is accomplished in a dehumidified room at 15°C and 15% RH. Seed stored for long-term conservation are sealed in aluminum foil pouches to maintain seed moisture content at 4-7%. There are two post-entry quarantine screenhouses for newly collected materials. Outgoing materials pass through the Taiwan Bureau of Commodity Inspection and Quarantine, Tainan Branch and are accompanied by phytosanitary statements. During multiplication plants are put inside net cages, staked, or pruned to prevent cross fertilization, thus maintaining genetic integrity of the accessions. Documentation facilities include microcomputers and an HP3000 minicomputer where the main databases are kept. Research Research has been conducted on seed treatments against seed-borne pathogens, breaking seed dormancy, distributionmethods using sweet potato meristem culture, and storability of vegetable soybean seed at different temperatures and moisture conditions. Current research include effect of ultra drying on stored seeds and cluster analysis in mungbean. Other research areas for future exploration are: diversity studies using additional techniques for measuring variation (e.g., biochemical, molecular, cytological) on the principal crops of AVRDC, procedures for strict maintenance of genetic integrity of accessions, genetic relationships between the Center's principal crops and their wild and weedy relatives, and other genetic studies that can enhance germplasm utilization, survey and detection techniques for seed-borne pathogens, and physiological studies on stored seeds. International collaboration Currently, GRSU is implementing a project titled "Conservation, Evaluation and Utilization of Vegetable Genetic Resources — A Collaborative Network Project for Southeast Asia" funded by the Japanese government. In this project, AVRDC works hand-in-hand with national program scientists. Training scholars from participating countries spend from 3 to 6 months in AVRDC to train on germplasm collecting

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Germplasm collection, evaluation,

strategies, evaluation, and data management. Collecting expeditions are undertaken jointly by national program scientists and GRSU staff. At the end of the project, important vegetable germplasm from Malaysia, Philippines, Thailand, and Indonesia would have been conserved in long-term storage. Since seeds of the collected materials together with passport, characterization, and evaluation data would be available from a central file, extensive utilization of the materials in germplasm enhancement programs is expected. The nationals trained through the project would form a pool of manpower skilled in plant genetic resources work which is expected to result in the upgrading of the participating countries' national programs in plant genetic resources. In addition, GRSU is also collaborating with national programs in the Philippines and Thailand on the multiplication and characterization of pepper and soybean germplasm, respectively. Conclusion As part of AVRDC, GRSU is committed to the attainment of AVRDC's mission. In addition, GRSU undertakes activities related to its being the global caretaker of the genetic resources of selected vegetable crop species. And lastly, it contributes to the scientific community by conducting research that will lead to a better understanding of vegetable genetic resources, its conservation and utilization.

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2

Introduction Concepts of Germplasm Conservation

L.M. Engle Geneticist and Head Genetic Resources and Seed Unit, AVRDC Shanhua, Tainan, Taiwan, ROC The conservation of crop genetic resources for evaluation and use in crop improvement is essential (1) to enhance agricultural productivity, especially in rural and urban areas of developing countries, and (2) to answer future needs. This paper presents what germplasm conservation is, the different methods of conservation, and conservation for evaluation and utilization. The need for genetic diversity The total variability within all the living organisms and the ecological complexes they inhabit is termed biological diversity or biodiversity. Biodiversity can be viewed at three levels: diversity in the ecosystem as reflected in the number of different environments in one system; species diversity as reflected in the different combination of species, and genetic diversity referring to the different combination of genes within each species. The importance of biodiversity has long been recognized. The most stable ecosystem is the tropical rainforest. It is also the most diverse. In the evolution of a particular species, genetic diversity is important. It is the raw material upon which many different genetic combinations are produced, combinations that enable a population to face the challenges of a changing environment (e.g., changing climate, new pests, new diseases). Populations have evolved systems to generate and maintain genetic diversity for in nature, diversity is the key to the survival of the species.

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Germplasm collection, evaluation,

Even under domestication, the role of genetic diversity is clear. Even before the first scientific plant breeder, farmers, and gardeners have used genetic variation in plants to develop new varieties. However, while man recognizes the existence of diversity and probably has a good idea of its significance, many of his activities lead to drastic reduction in biodiversity, including genetic diversity. This is contrary to the natural course of evolution and may lead to serious and irreversible consequences that will affect human survival. Genetic erosion The loss of genetic material (genes, genotypes) from individuals or populations is termed genetic erosion (IBPGR 1991). Changing patterns of landuse such as clearing of forests, housing, and industrial developments contribute to genetic erosion. So do changing cultural practices, particularly the widespread use of a limited number of standard varieties in lieu of the genetically rich old and traditional populations of cultivated species. The threat of genetic erosion is real. There are several recorded epidemics due to diminished genetic diversity resulting in increased genetic vulnerability in major crops (NAS 1972). 1840 1917 1943 Mid-1940s 1970–71 Famine in Ireland due to potato late blight (Phytophthora infestans) Wheatless days in the USA due to stem rust epidemics (Pucciniagraminis) Famine in Bengal, India, due to brown spot disease of rice (Cochliobolus miyabeanus) and a typhoon Complete elimination of all oats derived from the variety Victoria in the U.S. due to the Victoria blight disease (Helminthosporium victoriae) Southern corn leaf blight (Helminthosporium maydis) epidemic on all U.S. corn hybrids carrying the T-type cytoplasmic male sterility

In rice, recent epidemics associated with the widely grown and multiple-cropped semidwarfs have been pointed out (Chang 1979, 1984). Categories of plant genetic resources Genetic resources constitute all of the germplasm of plants, animals or other organisms, containing useful characters of actual or potential value. In a domesticated species, it is the sum of all the genetic combinations produced in the process of evolution (IBPGR 1991). Germplasm is the genetic material which forms the physical basis of heredity and which is transmitted from one generation to the next by means of the germ cells (IBPGR 1991). It also refers to an individual or clone representing a type, species, or culture that may be held in a repository for agronomic, historic, or other reasons (IBPGR 1991).

documentation, and conservation The major categories of the genetic resources of a crop species are: 1. Products of scientific breeding programs •

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Modern cultivars. The high yielding modern varieties (HYV, MV), including Fl hybrids, composites, and synthetics. Most have been selected for high uniformity and performance in intensive agricultural systems. Obsolete cultivars. Ecostrains of obsolete cultivars may persist in some areas (Chang 1985). Other products of plant breeding or genetic studies, i.e., advanced breeding lines, stocks, mutant and gene markers.

2.

Varieties of traditional agriculture • Landraces. The early cultivated form of a crop species evolved from a wild population (IBPGR 1991). Inherent diversity is a unique feature of the landraces. Many are varietal mixtures (Chang 1985). Primitive cultivars. These are crop forms grown under traditional agricultural systems, which have not undergone much improvement and which, in many cases, have developed from landraces selected by farmers (nonscientific breeding). They are often associated with a specific region or ethnic /tribal group and identifiable by vernacular names (IBPGR 1991).

•

® Special-purpose types. Special types from the areas of diversity which are adapted to specific ecological niches or provide special dietary or religious needs. 3. Wild and weedy relatives Wild species and weedy races belonging to the same genus as the crop species; may include related genera. These are mostly found in the primary centers of diversity. According to Vavilov, this is the region of true origin, identified by the presence of wild relatives, primitive characteristics, and high frequencies of dominant alleles (IBPGR 1991). All of these categories are targets of genetic conservation. However, the last two deserve special attention. Landraces are marked by diversification among races, within a race between sites and populations, and within sites and populations (Bennett 1970; Frankel 1972; Harlan 1975). Their genetic diversity expressed over space and time is likely to provide improved protection against climatic extremes and epidemics (Harlan 1975). On the other hand, wild species and weedy races are good sources of resistance to diseases and insect pests, tolerance to stress environments, cytoplasmic sterility, adaptability to different growing conditions, high nutritional value, improved quality, etc. (Harlan 1976; Hawkes 1977; and Hawkes 1983). The full financial value of wild relatives has been estimated by the California Agricultural Lands Project. A wild relative

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Germplasrn collection, evaluation,

of wheat from Turkey provided disease-resistant genes to commercial wheat varieties worth US$ 50 million annually to the United States alone. A single Ethiopian barley plant has a gene that now protects California's US$ 160 million annual barley crop from yellow dwarf virus, which is fatal to barley plants. A wild hop gave better bitterness to English beer and in 1981 brought US$ 15 million to the British brewing industry (Witt 1985). Genetic conservation Conservation is the management, preservation, and use of known genetic resources so that they may yield the greatest sustainable benefit to the present generation, maintaining their potential to meet the needs and aspirations of generations to come (IUCN-UNEPWWF 1980). Specifically, genetic conservation encompasses the collection, maintenance, and preservation of intra- and interspecific variation, e.g., a representative sample of the genetic variation of a particular species (IBPGR 1991). Chang's definition (1985) reflects more the planning, policy decisions, strategies, and management that go into a comprehensive genetic conservation as a "formulation of policies and programs which will allow the long-term preservation of genetic resources either in situ or ex situ in such a manner that the potential for continuing evolution or improvement would be sustained". Following this definition, a comprehensive genetic conservation program should include surveys, assembly of germplasm, multiplication or rejuvenation, evaluation, documentation, distribution/ exchange, preservation, training, and collaborative networking. Methods of genetic resources conservation There are two methods of conserving germplasm: in situ and ex situ (Frankel and Soule 1981). Conservation in situ involves the setting aside of natural reserves to conserve species in natural habitats. This type is also classified as dynamic evolutionary conservation. Plants and animals are conserved in entire biomes free to evolve through natural selection. Extinction of species is deterred but this method has little impact on useful plants. Conservation ex situ is the conservation of species out of their natural habitat (Hoyt 1988). There are three main methods of ex situ conservation: seed banks, field genebanks, and tissue culture. Collections of germplasm using any of these methods are called genebanks. With the advent of biotechnology a genebank may also include a collection of cloned DNA fragments from a single genome and, ideally, representing the whole of the genome. Seed preservation is by far the most convenient and efficient means of genetic conservation. Seeds are small and well adapted for storage. Most seeds are orthodox and can be dried to low moisture content and stored at low temperature without losing their viability (Hoyt 1988; IBPGR 1991). In contrast, there are recalcitrant seeds, which cannot be dried

documentation, and conservation

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and, therefore, cannot be kept at subzero temperatures without some damage from freezing (IBPGR 1991). Materials conserved in genebanks are of three types: 1. Base collection. A collection of genetic resource samples which is kept for longterm, secure conservation and is not to be used as a routine distribution source. Materials are only removed from a base collection for infrequent regeneration when seed viability has started to decline below an acceptable regeneration standard, or when stocks of an accession are no longer available from an active collection. Currently, base collections are only maintained for orthodox seed. In vitro base genebanks are being researched (IBPGR 1991). Active collection. A collection of accessions maintained for medium-term viability (about 30 years), stored at temperatures above 0°C but below 15°C, with 3–7% moisture content. It is normally larger than a base collection in both number of accessions and amount of seed and it usually contains material in the process of being evaluated and characterized, as well as material represented in base collections. Ideally, all accessions in an active collection should be maintained in sufficient quantity to be available on request (IBPGR 1991). Working collection. A collection of accessions usually used by a breeder for crop improvement or by researchers. The accessions are stored under ambient temperatures or in air-conditioned rooms. They are comprehensively tested and used in character selection, crossing, and hybridization (IBPGR 1991).

2.

3.

Material which otherwise would be difficult to maintain as seed, or of which it is desirable to maintain particular genotypes, are kept in ex situ collections of plants under field or nursery conditions. These are called field genebanks and, in general, fall within the category of active collections. These are areas of land in which collections of growing plants are assembled. In vitro active collections are stored as tissue culture in slow growth conditions. These may include protoplasts, single cells, cell suspensions, anthers, pollen, meristems, embryos, and calli. Cryopreservation is the storage of frozen tissue cultures at very low temperatures, e.g., in liquid nitrogen at -196°C. At this condition, all biological processes are suspended. Conserving for evaluation and utilization Evaluation is the essential link between conservation and use (Chang 1985). The first step is usually standardized morpho-agronomic characterization. Standardization is accomplished through a set of descriptor (characters) and descriptor states. IBPGR has published the descriptors of several crop species. To be useful, evaluation must be related to the breeders' needs. Usually these are characters related to high yield, resistance to pests and diseases, adaptation to different environments, and improved quality. The range of characters is very diverse and would

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Germplasm collection, evaluation,

require a multidisciplinary team and an interdisciplinary approach. However, although ti me-consuming and expensive, systematic evaluation is necessary if use and benefits derived from the conserved germplasm is to be maximized. An equally important component of a utilization-oriented genebank is distribution of plant material and information. Conclusion Germplasm conservation encompasses a web of complex interrelated activities. Genebanks, now preferably called plant genetic resources (PGR) centers to reflect it as more than just a storage place, take care of the bulk of the germplasm conservation for crop plants. To be able to do its job satisfactorily a PGR center requires facilities designed for long-term operation and trained manpower. In many cases no single person, team, or center can take care of all the tasks of genetic resources conservation. The strategy of networking activities and responsibilities is thus gaining popularity. The need for germplasm conservation cannot be overemphasized. Genetic erosion is irreversible, and once a genetic component is lost from human control, it is impossible to reconstitute it by known scientific means, hence, the expression "irreplaceable germplasm". While germplasm collections are expected to serve breeding programs today, they are also conserved to serve future needs. They constitute an inheritance for our children and grandchildren for hundreds of years to come, a heritage that should be handled with sacredness. References Bennett, E. 1970. Exploration in agriculture and horticulture — Introduction. In Frankel, O.H., and Bennett, E. (ed.). Genetic Resources in Plants — Their Exploration and Conservation. Blackwell Scientific, Oxford and Edinburgh. Chang, T.T. 1979 (as cited in Chang 1985). Genetics and evolution of the Green Revolution. In de Vicente, R. Replies from Biological Research, Consejo Superior de Investigationes Cientificas, Madrid. Chang, T.T. 1984. Conservation of rice genetic resources: luxury or necessity? Science 224:
251-256.

Chang, T.T. 1985. Principles of genetic conservation. Iowa State Journal of Research 59: 325348.

Frankel, O.H. 1972. The Significance, Utilization and Conservation of Crop Genetic Resources. FAO, Rome. Frankel, O.H. and Soule, M.E. 1981. Conservation and Evolution. Cambridge University Press, Cambridge.

documentation, and conservation Harlan, J.R. 1975. Our vanishing genetic resources. Science 188: 618-621. Harlan, J.R. 1976. Genetic resources in wild relatives of crops. Crop Science 16: 329-333.

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Hawkes, J.G. 1977. The importance of wild germplasm in plant breeding. Euphytica 26: 615621. Hawkes, J.G. 1983. The Diversity of Crop Plants. Harvard University Press, Cambridge, Massachusetts, USA 184 pp. Hoyt, E. 1988. Conserving the Wild Relatives of Crops. IBPGR, IUCN, WWF. IBPGR. 1991. Elsevier's Dictionary of Plant Genetic Resources. Elsevier, Amsterdam, New York, Tokyo, Oxford. IUCN-UNEP-WWF. 1980. World Conservation Strategy. IUCN, Gland, Switzerland. NAS. 1972. Genetic Vulnerability of Major Crops. National Academy of Sciences, Washington, D.C. Witt, S.C. 1985. Briefbook: Biotechnology and Genetic Diversity. California Agricultural Lands Projects, 227 Clayton St., San Francisco, California 94177, USA 145 pp.

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Germplasm collection, evaluation,

3

Genetic Resources and Their Role in Improvement Horticultural

Obaidul Islam
Principal Scientific Officer Genetic Resources Centre, BARI Joydebpur, Gazipur, Bangladesh Genetic resources play an important role inmodern agriculture by increasing production in quality and quantity through introgression of desirable genes under elite background. The classical example of the perils of a too-narrow genetic base is documented in the Irish potato famine that occurred between 1846 and 1851. Nearly all varieties of potatoes then grown were derived from closely related germplasm sources. When a formerly obscure blight struck, the crop was uniformly susceptible. In the USA the southern corn leaf blight alerted breeders of all major crops to increase their efforts to broaden the genetic base. The importance of genetic resources is now widely and well understood.

Genetic resources
Genetic resources are the carriers of genes encoding all the genetic traits that have been accumulated over several billion years. In plants, genetic resources supply the genetic variation useful for crop improvement through breeding, including biotechnology. These may be seed, bulb, cuttings, tuber, and other plant parts, etc. that include the following categories: • Landraces and primitive cultivars ® Obsolete cultivars • Modern cultivars

documentation, and conservation Advanced breeding lines Wild relatives

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Germplasm is the part of any living cell, be it bacteria, plant or animal, controlling hereditary characteristics. It determines those characteristics passed on to an organism's offspring. Exotic germplasm is any germplasm that is not currently being used in a particular country. This is in contrast to "elite" adapted germplasm that has undergone a great deal of selective breeding and natural selection in the area of use. We do not know the extent of the genetic potential of crop species diversity existing on our planet. This is because of the scope offered by genetic diversity for natural and human selection to detect genotypes tailored to diverse agroecological and socioeconomic needs. Acquisition, characterization and evaluation, genetic diversity research, and germplasm conservation of genetic resources are pre-breeding work for a crop improvement program. Genetic diversity research is needed because of its emphasis on broadening the genepools in a collection with representative samples of related wild species. This can be studied at three levels: (1) intraspecific, (2) interspecific, (3) ecosystem. The relationship among these three levels is important for its scope of uses in a breeding program. This could be investigated by studies on chromosomes, reproductive biology, isozyme pattern, and simple cross behavior. On the other hand, within the level, germplasm should be classified through D 2 and Metroglyph analysis based on characters needed to be improved. Ecotypes are valuable as breeding materials with their tolerance to environmental stresses (cold, snow, heat, wet, and drought). Germplasm enhancement (pre-breeding) Germplasm enhancement should be given emphasis in existing and future improvement programs mainly to transfer desirable genes to elite background and in developing new and efficient plant types and in genetic adjustment (photoperiod response). The breeder grows the progeny of the crosses and selects individual plants which combine the good traits of both parents. In this way desirable traits are transferred from exotic germplasm into usable, adapted breeding lines. Germplasm enhancement is also equally important for genetic resistance and quality breeding where wild and exotic germplasm are important. Identification of parents, useful traits and their genetic nature A fruitful breeding program depends upon parental materials selection and inheritance studies on useful traits to be improved. These may be qualitative or quantitative traits. The germplasm could be exploited intraspecifically as: (1) good general and specific combiner, (2) isogenic line, (3) male sterile line, and (4) self-incompatible line; and interspecifically as genetic resistance.

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Germplasrn collection, evaluation, G A combining ability study among the germplasm could provide information on particular germplasm as to benefits for specific trait improvement. • • An isogonic line may add only one different gene in the same genetic background. A male sterile line is being used commercially, particularly in vegetable hybrid seed production (onion, radish, etc.). It has been necessary to develop suitable cytoplasm — genetic male sterile, maintainer, and restorer lines to make hybrid onion and radish commercial successes. A self-incompatible line is more economical than a male sterile line since it has the capability to produce hybrid seed in both parents.

•

Potential use of genetic resources Disease resistance
Breeding for disease resistance in tomato uses some wild relatives such as Lycopersicon esculentum v. ceraciforme b., L. peruvianum, and L. pimpinellifolium for resistance to leaf mold, Fusarium wilt, and root-knot nematode. In addition, the rootstocks of Solanum torvum and S. toxicarium were found to be resistant to Fusarium wilt and tolerant to bacterial wilt, verticillium wilt, and root-knot nematode. One S. torvum line has been registered as rootstock variety 'Torvum vigor' and widely distributed to eggplant growers. 'Trifoliate orange' is used as rootstockin S. Union for exocortis disease resistance. Raphanus brassica showed highest resistance to clubroot disease.

Resistance to stress Feroniz limonia, a citrus-related genera, has exceptional water tolerance and has been
used as rootstock of citrus in lowland areas of Thailand. 'Goutouchen', a genotype, is used in sour orange as rootstock because of its strong tolerance to salt. Summer cabbage and summer tomato were found to be tolerant to high temperature.

Modification of plant habit Citrus atalantia proved to be very good dwarf rootstocks and bears fruit 2–3 years earlier than those commonly used such as C. grandis, rice, wheat, tomato, banana, and beans. Quality
Fruit shape, color, and total soluble solids (TSS) in grapes, apples, watermelon, and melon are the remarkable outcomes of diverse germplasm uses.

documentation, and conservation
Yield improvement

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1. Timing and breeding system • Uses of cytoplasmic and genetic male sterility in onion, tomato, and chili. • Induction of polyploidy in potato and grapes. 2. S alleles
G

Strong S allele was found in kale and can be transferred to brussels sprout. Induction of parthenogenesis in citrus, cucurbits, and grapes has potential.

Allelic diversity in sweet potato is well known to result in higher yield (heterosis). Ease of use of genetic resources This may depend on hybrid sterility, ploidy level, phylogeny, and geographical distribution and linked genes. Level of difficulty 1. Distribution of cultivars and resources overlaps and introgression is already taking place, e.g., in S. melongena and S. indicum. 2. Wild and cultivated plants in separate genepools but hybrid fertile, e.g., L. esculentum and L. pimpinellifolium. 3. Wild and cultivated plants of different chromosome numbers or different genomes but hybrid or amphidiploids may be fertile, e.g.,
Brassica spp., niagra, oleracea, campestris.

n=8 n=9 n=10 4. Special techniques required to bring about transfer of genes: ® Bridging species 4x X 6x may not be fertile but 4x X 2x > 3x doubling 6x X 6x is fertile > bridge sp. • Embryo culture: cucurbits, grapes • Irradiation of pollen ® Protoplast fusion for Brassica and Solanum and in vitro fertilization for Petunia

22 Benefits from a broader genetic diversity

Gennplasm collection, evaluation,

Sustainable yield per unit area can also be increased by improving the ability of the crop to produce dependably —in spite of stresses imposed by soil, pest, and adverse weather. This requires careful selection and modification of the germplasm before it can be introduced into breeding. Nutritional quality of produce may be greatly improved by incorporation of traits present in germplasm but which are not being used. The breeder sometimes faces problems due to lack of appropriate genetic resources for crop improvement. Therefore, the unrestricted flow of exotic germplasm from its origin as well as its availability from genebanks to the breeder in all countries should be assured.

documentation, and conservation

23

Germplasm Collecting Strategies

L.M. Engle Geneticist and Head Genetic Resources and Seed Unit, AVRDC Shanhua, Tainan, Taiwan, ROC

Collecting germplasm is not easy. It is time-consuming, costs a lot of money, and may endanger the health and even life of the collector. It is, therefore, important that collecting be done only because there is a recognized need for it. Actual exploration and collecting is only one of the means to assemble a germplasm collection. Additional means are by donations and seed exchange with institutions or individuals holding a portion of the germplasm. Why assemble a germplasm collection? There are many reasons for the establishment of a germplasm collection. In many cases, a germplasm collection is assembled because there is a need for the germplasm in crop improvement programs. That is why initial germplasm collection is usually done by plant breeders. Plant breeders and other research workers require genetically diverse materials to be able to continuously develop improved types and varieties of crops that can face the challenge of an environment that is both evolving and becoming limiting. A genetically diverse genepool is the raw material from which the plant breeder will mold new varieties. The availability of specific genes in the collection determines the success of the plant breeder in fashioning out a variety with specific characteristics. The more diverse a genepool is, the higher is the probability that it would contain the desirable genes. Secondly, there is a need to conserve endangered species. Change and development in agriculture and landuse increase the risk that species, both cultivated and wild, will be lost in the future. "It is a matter of moral principle to deter the extinction of useful plant species" (IUCN-UNEP-WWF 1980).

24

Germplasm collection, evaluation,

And, thirdly, there is a need to conserve for future needs. "The preservation of genetic diversity is both a matter of insurance and investment for sustaining and improving future food resources" (Chang 1985). It, therefore, means that germplasm should be assembled not only to serve our current needs but also as a safeguard against unforeseen circumstances in the future. Once the need to assemble a germplasm collection has been established, one can be assured that the collection will be a meaningful one and he can then proceed to determine the scope of the collection and the strategy to use in assembling it. Actual exploration and collecting can be very expensive in terms of time, financial, and personnel resources. Therefore, effort should be allocated to planning a systematic and rational strategy to follow. Planning time may take from 3 to 12 months depending on the experience of the collecting team and their familiarity with the crop and the area. The strategy may be based on the following considerations (Harlan 1956; Frankel and Bennett 1970; Frankel and Hawkes 1975; Hawkes 1976; Clements and Cameron 1980; Hawkes 1980; Chang 1985; Brown et al. 1989; Bakhareva 1990): Species coverage and species prioritization In setting priorities, the genepool concept of Harlan and de Wet (1971) which reflects ease of utilization can be used as a guide (Fig. 1-3). In this concept, crop species and their relatives are grouped into the following: Primary genepool (GP-1) — the true biological species including cultivated races and spontaneous races (wild and / or weedy). Within this genepool, crossing is easy. Hybrids among these are more or less fertile, chromosome pairing is good, segregation normal, and gene transfer to the crop is simple. Secondary genepool (GP-2) — the coenospecies from whose members gene transfer is difficult but possible. Hybrids may be weak or partially sterile, chromosomes may pair poorly, and there may be differences in ploidy level. Tertiary genepool (GP-3) — from which moving genes is very difficult. Hybrids tend to be anomalous, lethal, or completely sterile. Gene transfer is either not possible with known techniques or may be possible but with the use of extreme, radical measures such as the use of embryo culture, chromosome doubling, or bridging species. This genepool represents the outermost limit for breeding by conventional means, but it is often ill defined due to lack of research. The International Board for Plant Genetic Resources (IBPGR) used four criteria in determining its crop priorities (IBPGR 1981): 1. the risk that genetically diverse materials of the species and their wild relatives will be lost in the future, particularly the near future, as a result of change and development in agriculture and landuse including the introduction of new varieties. Since such changes are generally local, a species or group may have high priority in one country or region and lower priority elsewhere;

documentation, and conservation

25

Hybrids with GP 1 anomalous, lethal, or completely sterile

Gig -1 Subspecies A: Cultivated races Biological specios
Subspecies B: spontaneous races

GP-

1i

sene transfer not possible requiring radical techniques

Fig.1. Schematic diagram of primary genepool (GP-1), secondary genepool (GP-2), and tertiary genepool (GP-3) (from Harlan and de Wet 1971)

26

Germplasm collection, evaluation,

well represented in collection few numbers of accession in collection not represented in collection

Capsicum chacoense C. galapogense C. schottianum C. buforum C. scholnikianum

Acc. 2017 SA. 393

Fig. 2. The genepool of Capsicum and the degree of representation in the AVRDC collection

documentation, and conservation

27

J

}

well represented in collection few numbers of accession in collection not represented in collection

Vigna grand/flora V. lanceolata V. luteola V. marina V. vexillata

Fig. 3. The genepool of Vigna and the degree of representation in the AVRDC collection

28

Gerrnplasm collection, evaluation, 2. the economic and social importance of the materials to be collected measured in terms of their present usefulness and importance (volume or value of production and trade, numbers of people depending on or using them), as well as their expected, intended, or potential contributions to development (including the improvement of human diets and the income and well-being of farmers and other rural people) and the economic and social progress of mankind; 3. the recognized requirements of plant breeders and research workers, in both developing and developed countries, for genetically diverse materials (including advanced breeding lines), and the expected significance in economic and social development of the improved types and varieties of crops they will be able to produce with these materials; and 4. the size, scope, and quality, including documentation, of existing collections.

Based on the above criteria, IBPGR prepared a list of the priorities among crops in 1975, revised in 1981. Some countries have National Committees on Plant Genetic Resources which determine the priority species for collection and conservation. International agricultural research centers with specific mandate crops and many smaller institutions have their own priority lists. To further confirm the need for collecting, conduct a survey of the work that has been done. Prepare a listing of germplasm holdings for the species of interest. In this way one can make sure that there will be no useless duplication of effort. One must remember that a collection can also be assembled through donations and seed exchanges. A good reference on current germplasm holdings is the IBPGR Directory of Germplasm Collections. It is also necessary to evaluate the current status of the genetic resource of the species. Obtain the most up-to-date information on specific diversity of wild plants, threatened landraces, new varieties, hybrids, and lines. If possible determine the total range of genetic variability within the species. Remember that a comprehensive collection carries the maximum diversity of the species. There are cases where the need to add to a collection is due to the recognized need for specific traits. Finally, decide on whether the mission will be a generalized one, covering many species, e.g., all crop species, all wild species, or a specialized collecting of a single crop. Where several related or unrelated crop species grow together, multiple-crop collecting would be cost-effective and should be done. However, there are cases where each crop species occurs in distinct agroecological zones, .making multiple-crop collecting impractical (e.g., cotton and Quinoa in the Andes, Hawkes 1980; wild rice). Geographic coverage and geographic prioritization The priority areas to be covered by the exploration mission can also be determined from the information used to determine species coverage and species prioritization. Divide the area into distinct regions based on either geobotanical data, political, or administrative units.

documentation, and conservation

29

IBPGR has also set criteria to determine priorities among regions (Fig. 4. —IBPGR 1981): 1. 2. that they contain significant genetic diversity of one or more crops or species selected according to the criteria set for crops; that change and development in agriculture, and/or change in landuse, are occurring in them at such a rate that if nothing is done, genetically diverse materials are likely to be lost; and that widespread crop failures have occurred or are imminent, or reasonably to be expected, on such a scale that diverse materials are likely, if nothing is done, to be lost.

3.

Determine distribution and identification of the original habitats and areas occupied by the group(s). A visit to herbaria and a review of previous collecting trip reports in the area can provide these information. On a global scale, the concentration can be on the primary centers or origin . of diversity, the secondary centers, and subcenters of diversity. Determine those parts in which the greatest intraspecific variability is to be found, and particularly the geographic centers in which endemic characters are most numerous. Determine similar patterns in cultivated and noncultivated species. Survey past efforts. There may be no need to visit some areas. Give due attention to ecological considerations. Therefore, in planning the exploration and collecting mission, consider also the following: clinal distribution vs. mosaic distribution, parallel ecotypic differentiation and agroecological factors such as climate, topography, edaphic factors, altitude, cultivation pattern, and harvesting pattern. Finally, based on the above, map out the existing collections and the areas proposed to be covered by the expedition. Time considerations There are physical limits to the time one can be out collecting and the amount of materials that can be collected. The duration of the collecting mission depends on favorable weather conditions and time of harvest of the species. It is, therefore, a good idea to have data on annual rainfall and distribution pattern as well as planting and harvest seasons for cultivated crops. The usual duration of a collecting expedition is 15 to 45 days. Sampling intensity varies from 10 to 20 samples per day. Therefore, a collecting expedition usually cannot expect to collect more than 1,000 samples. Implementing the collecting strategy
1.

Assembly of the collecting team
The collecting team usually consists of three to five experts. If possible, include one who knows the area of coverage and possesses a good command of the native language. Designate a team leader who will coordinate all activities. Brief them on

Pig. 4. The IBPGR regional priorities as of 1981

documentation, and conservation

31

the significance of the germplasm collection and conservation to be conducted. Also, familiarize the team on the procedures to be followed and strategies to be taken during the collecting trip. It is ' best to include local counterparts in the collecting team.

2.

Collecting permits and quarantine requirements
Before embarking on the actual expedition, make sure that you have the necessary collecting permits. Most countries have definite policies on collecting of biological materials. Inform local authorities and observe order of protocol. A list of consulates and offices to contact would be helpful. Inquire about quarantine regulations, especially in the final destination of the collected materials. This will facilitate movement in the area to be explored and can avoid possible loss of expensively collected material. Collectors should have proper inoculations and health certificates for international travel.

3. Materials needed for the expedition
Prepare a checklist of equipment and supplies needed during the trip. One week before the scheduled collection trip, prepare all the materials. Check each item before setting out on the field trip (Table 1). 1.1 A fully covered motor vehicle, preferably a four-wheel drive, is needed to reach remote areas. The vehicle should always be in tip-top condition during this kind of expedition trips. It should have enough room for the collecting team, the collecting supplies, and the collected materials. Its layout should be such that it would be easy for persons and materials to get in and out. Information on road conditions can also help in deciding what type of vehicle to use. 1.2 Collecting forms, seed envelopes, cloth bags, net bags, tags, writing pens, stapling wires, and maps are the basic supplies needed for the trip. 1.3 Optional materials are chemicals for seed drying and seed treatment and fixatives. 1.4 Official papers and letters to local agencies in the area and identification cards are necessary and could come in handy to avail help from local government officials.

4.

Sampling procedures
The sampling procedure to be followed should aim at the fullest possible recovery of the genetic variation of the species, irrespective of the relative frequency or rarity of any genes or linked genetic complexes. The operational sampling unit is the field. The unit of ecotype distribution is the village or river basin or isolated valley.

32

Germplasm collection, evaluation,

litJ of nrd*rle Vehicle

;, needed for a collet:1a

Collecting forms journal or field notes Camera and him Checklist of plants to be collected: botanical name, synonyms, folk names, distribution uses, and plant parts used good flora of the region. Paper, cloth, net bags, plastic bags lags and labels Rubber bands asking tapes Cords Scissors Pruning shears Permanent marking pens Pencils Spade Bolo (knife) Altimeter Magnifying glass Measuring tape Herbarium press Gloves Boots First aid kit

documentation, and conservation

33

Sampling can also be done in the farmer's seed store and the marketplace. However, experience has shown that very often seeds from these sources have low viability. Random vs. biased sampling. Field sampling is done by randomly selecting a starting point and taking seeds regularly as one goes through a series of transactions within the fields so that sampling of the population is well represented in the collected samples. A biased sampling based on phenotypic selection is then added to the random samples. Biased sampling alone based on phenotypic selection is not recommended since phenotype is often modified by the environment. Sample only from healthy looking plants as much as possible at the time that seeds are at their highest viability. Clustered sampling. For sampling wild species, use a clustered pattern of sampling. This is due to the difference in the population structures of wild species which are highly heterozygous as compared to traditional varieties. Grids. Division of the area, even of the whole country into grids, maybe useful when the materials to be collected are almost evenly distributed throughout the area.

5. Effective sample size
Infield sampling, collect from as many plants as possible. In rice, the recommendation is one panicle per plant from 50 plants per site. For many crops, a random sample of 50 to 100 would be adequate (Marshall and Brown 1975). For wild species, collect as many as possible representing the whole population, since wild populations are heterogenous in nature.

6. Tags and labels
For tags and sample labels, use waterproof permanent marking pens. Fill in duplicate tags with the following information. Collection No.: Collection Date: Variety Name: Barangay: Town: Province: LME-91-44 3 /4 / 91 AZUCENA BAYBAYIN LOS BANOS LAGUNA

Collector's Name: L.M. ENGLE Farmer's Name: J. DELA CRUZ

This information is also described in the collecting forms.

4

Germplasm collection, evaluation,

7. Sample containers
Put whole panicles in cloth bags or net bags; put one tag inside and close the bag by string, then tie a duplicate tag on the bag. For seed samples, put threshed samples in double-strength paper bag, then put one tag inside and close using a stapler. Staple a duplicate tag on the outside of the paper bag. Avoid the use of plastic bags, since moisture and heat can accumulate inside and may cause loss of viability.

8. Processing of samples
Samples should be processed at the collection site only if they are wet and bulky for transport. Drying should be done only by aeration. If threshing is done, put the seeds in double-strength paper bags, then transfer the tags to the new containers. Do not sun dry or put on hot concrete floors because this might affect the seed viability.

9. Sample packing for transport
Place sample in brown bags or plastic if properly dried and send directly to its destination The collected materials must reach the destination genebank in the shortest time possible. Send samples by courier, the soonest after collecting the samples. Do not wait until you have accumulated a large number of samples. This delay may affect the viability of the seeds if not processed immediately. When transporting germplasm to different areas, always follow local or international quarantine measures implemented in the area.

10. Documentation procedures during collection
Collecting data, if properly taken, can provide many useful information e.g., adaptive characters, genetic and breeding potential, ecological properties, etc. A collecting form was designed by the IBPGR. This form is very similar to the ones used by the International Rice Research Institute and AVRDC. Although these forms take some time to fill out and may be cumbersome, they must be filled out in the collecting site. Very often it is after one has finished with the collecting mission that one realizes how important filling out the forms is. Fill out collection forms as completely as possible during or right after the collection of the samples. Photograph the area or sampling sites or anything that can provide information about the sample and the collection site. This could be very useful in the presentation of the trip report and the documentation of the field collection.

documentation, and conservation

35

A field collection notebook filled up like a diary will be useful in the preparation of the field collection report.

Field collection report
The team leader should prepare a field collection report that is as informative as possible. It should cover the itinerary, highlights of observations on local flora, cultural practices, and annotated maps as well as photographs showing collection sites, ecological features and other information. The collection report is best done as soon as the collector reaches his base station while memories of the details of the exploration are still fresh in his mind. If the collector has a well-kept journal regularly filled during collecting, the report will be easy to prepare. The field collection report and the collection forms are official documents that properly acknowledge the collector and his agency for the collection. It can later be published so that any paper or report that makes use of the collection can cite the report.

Distribution of the collected material and information
There should be a scheme for depositing materials in the home country, international research centers, and the center of the proponent. The plant materials should be accompanied by at least the passport data and the field collection report. Conclusion A well planned collecting expedition will result in a good collection representing the maximum diversity in the species and with information useful not only in the utilization of the collected material but in understanding the ecology and other biological properties of the species. It will also avoid unnecessary expense in time, financial resources, and personal services. The assembly of individuals that represent the genepool of the species is only the initial step in genetic conservation. Since it entails considerable time, effort, and money there should be serious attempt to preserve and utilize the information and materials generated from the exercise. References Bakhareva, S.N. 1990. The USSR policy for exchanging genetic resources and the germplasm collection procedures of the Vavilov Institute. Diversity 6 (3 & 4):10-12. Brown, A.H.D., Frankel, O.H., Marshall, D.R., and Williams, J.T. (ed.). 1989. The Use of Plant Genetic Resources. Cambridge University Press, Cambridge, New York, New Rochelle, Melbourne or Sydney. p. 382. Chang, T.T. 1985a. Principles of genetic conservation. Iowa State Journal of Research 59: 325348.

36

Germplasm collection, evaluation,

Chang, T.T. 1985b. Collection of crop germplasm. Iowa State Journal of Research 59:349-364. Clements, R.J. and Cameron, D.G. (ed.). 1980. Collecting and Testing Tropical Forage Plants. Commonwealth Scientific and Industrial Research Organization. Melbourne, Australia. p. 154. Frankel, O.H. and Bennet, E. (ed.). 1970. Genetic Resources in Plants — Their Exploration and Conservation. IBP Handbook No. 11. F.A. Davis Co., Philadelphia. p. 554. Frankel, O.H. and Hawkes, J.G. (ed.). 1975. Crop Genetic Resources for Today and Tomorrow. Cambridge University Press, Cambridge, London, New York, or Melbourne. p. 492. Harlan, J.R. 1956. Distribution and utilization of natural variability in cultivated plants. Brookhaven Symposia in Biology 9:191-208. Harlan, J.R. and de Wet, J.M.J. 1971. Toward a rational classification of cultivated plants. Taxon 20:509-517. Hawkes, J.G. 1976. Manual for Field Collectors (seed crops). AGPE, Misc /7. FAO, Rome. Hawkes, J.G. 1980. Crop Genetic Resources Field Collection Manual. International Board for Plant Genetic Resources and European Association for Research on Plant Breeding (EUCARPIA). Druk Pudoc, Wageningen. 37 pp. IBPGR. 1981. Revised Priorities Among Crops and Regions. IUCN-UNEP WWF. 1980. World Conservation Strategy. IUCN, Gland, Switzerland. Marshall, D.R. and Brown, A.H.D. 1975. Optimum sampling strategies in genetic conservation. In Frankel, O.H. and Hawkes, J.G. (ed.). Crop Genetic Resources for Today and Tomorrow. Cambridge University Press, Cambridge, London, New York or Melbourne. pp. 53-80. Vavilov, N.I. 1951. The origin, variation, immunity and breeding of cultivated plants. Chron. Bot. 13:1-364. Cited in Frankel, O.H. and Bennet, E. (ed.). 1970. Genetic Resources in Plants — Their Exploration and Conservation. IBP Handbook No. 11. F.A. Davis Co., Philadelphia. p. 554.

documentation, and conservation

37

Genetic Diversity

Local Vegetables

S.M. Monowar Hossain1 and M. Mozammal Hoque2 'Principal Scientific Officer and Head 'Principal Scientific Officer Vegetable Section, Horticulture Research Centre, BARI Joydebpur, Gazipur 1701, Bangladesh
Bangladesh produces different indigenous vegetables. These vegetables include hyacinth bean, teasle gourd, bottle gourd, pumpkin, bitter gourd, ash gourd, sponge gourd, ribbed gourd, red amaranth, stem amaranth, and brinjal among others. The vegetables are represented by different local varieties and landraces which are scattered all over Bangladesh. It is most likely that many of the germplasm have already disappeared or are threatened to total extinction due to the absence of concerted efforts of collection, evaluation, documentation, and conservation. In recent years, attempts have been made to collect and evaluate germplasm of some important local vegetables. The collection and evaluation of germplasm were on a limited scale due to constraints in funds and logistic support. It is imperative to collect both local and exotic germplasm of vegetables to develop varieties with higher yield, better quality, resistance to common diseases and insects through selection and hybridization. Hence, germplasm collection, evaluation, and conservation programs need strengthening. In this paper, the genetic diversity of two local vegetables, namely hyacinth bean and teasle gourd (kakrol), are described. Hyacinth bean (Lablab purpureus L.) is a popular and nutritious vegetable in Bangladesh generally grown in homesteads. In Chittagong, Syihet, and Jessore, it is cultivated commercially. To assess the genetic diversity of this vegetable, a comprehensive program was undertaken to collect germplasm from different regions of the country and subsequently evaluate them at BARI.

38

Germplasun collection, evaluation,

Collecting
So far, more than 415 germplasm accessions have been collected from the different districts in the country. Most have been collected from the main cultivation areas, namely, Chittagong, Sylhet, Jessore, Comilla, Noakhali, Bogra, and Dhaka. The farmer's field, kitchen gardens, and local seed traders were tapped as sources of germplasm accessions. BARI scientists as well as extension staff of the Directorate of Agricultural Extension were involved in the collecting. They collected seeds from the rural areas, local markets, and through personal contact. The collecting program was started in 1989. In 1990-1991, 232 germplasm accessions were evaluated by maintaining a single row of four plants per germplasm accession; the remaining germplasm was evaluated in 19911992.

Evaluation
Results of the evaluation of 232 germplasm accessions indicate that a wide range of genetic diversity exists in terms of morphological, physiological, and yield-contributing characters. Maximum variability was observed in yield / plant followed by pod breadth and length, and days to maturity and flowering (Table 1). The flower color had wide variability representing white, light purple, purple and deep purple. The majority of the flowers were purple. The early maturing germplasm accessions had white flowers. In 232 lines, days to flowering ranged from 67 days to 165 days and days to first harvest 87197. The pod shapes were sickle, semisickle, and straight with flat, inflated, and intermediate forms. Different pod colors such as green, white, creamy purple, and green with purple margin were observed. The mature seeds had white, black brown, and spotted coats. Enormous variability was found in pod size. The length varied from 6.1 to 18.2 cm and breadth ranged from 1.07 to 3.9 cm. Yield varied from 1.15 to 2.8 kg / plant. Accordingly, the germplasm was grouped into early (90 days), medium (120 days), and late (120 days). All the germplasm accessions were attacked by aphids; anthracnose infestation had certain degrees of variability.

Table 1. Variability of different characters of hyacinth bean
Characters Days to flowering Days to maturity Pod length (cm) Pod breadth (cm) Yield/ • lant (k :) 67.00 87.00 6.10 1.01 1.15 Range - 165.0 - 190.0 18.2 3.9 2.8 Mean 120.30 ± 0.75 148.82 ± 0.81 9.56 ± 0.21 2.21 ± 0.15 2.1 ± 0.25 SD 15.73 19.69 2.25 0.63 0.41 CV% 5.46 6.38 15.36 29.49 35.46

documentation, and conservation

39

Kakrol (Momordica dioica R.) used to be a minor vegetable. Hence, very little work was done on variety development or development of its production technology. At present, it is a very popular commercial vegetable in Bangladesh both for the domestic market and export. It can withstand handling in transportation and has good shelf life. A summer vegetable, kakrol is popular in the domestic market when there are not many varieties of vegetables available. A project entitled "Germplasm collection and evaluation of kakrol" was undertaken with financial assistance from the World Bank to obtain information on its genetic variability. Data were obtained from literature, including national dailies, production people, and also experienced horticulturists and agriculturists. Brahmanbaria is the most concentrated kakrol production area. The other places identified for kakrol production were Gazipur, Khagrachari, Kaptai, Mymensingh, Feni, Jamalpur, Norshingdi, and Tangail. Kakrol was also studied in situ, and its germplasm collected. Twenty-seven germplasm accessions of kakrol were collected from September 1990 to January 1991 (Table 2). The germplasm collected was planted at the Central Research Station, Joydebpur, using 1.5 x 1.5-m spacing for evaluation. The information obtained on kakrol during summer 1991 are summarized and presented in Table 2. A lot of variability exists in days to first female flower, days to first harvest, shape of the fruit, skin color at marketable stage, individual fruit weight, number of fruit / plant, and yield / plant. For the 27 lines, days to first female flower ranged from 41 to 170 days, while days to first harvest varied from 64 to 215 days. Fruit shape varied from oval to cylindrical. Three colors of kakrol fruit were observed at the marketable stage: green, light orange, and yellowish. The fruit is found to reach marketable stage in about 12 days from flowering in 26 lines but KK0025, a wild type, required 45 days. Individual fruit weight ranged from 33.9 to 635 g among the 27 lines. Enormous variability was also observed in the number of fruit borne per plant. It ranged from 6 to 120 fruits / plant. Yield varied from 0.33 to 6.66 kg/plant. The evaluation of the germplasm of these two local vegetables clearly indicates that new varieties with high yield potentials and with different maturity durations and resistance to common pests and insects could be developed through selection. They could also be utilized in hybridization programs for improvement. It is very essential to focus more attention on exploring and conserving the genetic resources of these indigenous vegetables before they are completely eroded.

40

Germplasm collection, evaluation,

Table 2, Yield and yield-contributing characters of 27 kakrol lines Shape Fruit color Individual Fruit/ Acc. no. Days to Days to first first at marketable fruit wt. plant female harvest stage (g)
flower

Yield/ plant (kg)

I(1(0001 KK0002 KK0003 KK0004 KK0005 KK0006 KK0007 KK0008 KK0009 KK0010 KK0011 KK0012 KK0013 KK0014 KK0015 KK0016 KK0017 KK0018 KK0019 KK0020 KK0021 KK0022 KK0023 KK0024 KK0025 KK0026 KK0027

69 71 99 69 79 41 57 65 56 83 59 56 74 89 75 77 76 55 67 89 64 46 58 58 170 115 69

86 86 127 86 97 65 68 79 70 104 71 75 86 112 98 111 89 71 81 102 72 64 77 70 215 135 86

Spindle Oval Cylindrical

Light orange Green

Spindle O. al Spindle Oblong Spindle

Yellowish Green Green Light orange Yellowish Light orange Green "

Oblong . " Oval Cylindrical Spindle Oval Oblong Cylindrical Oval Spindle Oval Oval Oblong Oblong

Light orange Green Light green Yellowish Light orange Green Light orange Green

51.0 58.7 67.4 51.4 56.4 57.1 64.4 58.7 122.2 56.1 46.5 67.7 44.6 58.3 60.7 36.8 66.9 60.3 52.2 96.3 66.3 62.9 59.0 33.9 635.0 88.5 85.7

68.0 46.0 35.0 47.0 118.0 77.0 74.5 58.3 38.3 26.2 29.0 42.0 22.5 35.0 38.0 9.0 56.5 66.5 34.2 20.0 50.5 48.5 29.3 120.0 6.0 23.0 14.0

3.47 2.70 2.36 2.42 6.66 4.40 4.80 3.42 4.68 1.47 1.35 2.85 1.10 2.04 2.31 0.33 3.78 4.00 1.79 1.93 3.35 3.09 1.73 4.07

1.20

documentation, and conservation

41

Characterization

Germplasm

L.M. Engle Geneticist and Head Genetic Resources and Seed Unit, AVRDC Shanhua, Tainan, Taiwan, ROC Introduction Germplasm collections are assembled and maintained primarily because of their potential use in crop improvement in the present and in the future. The collection aims to provide abroad genetic base from which plant breeders can obtain desirable genotypes. Therefore, for the materials in the genebank to be of interest to the breeder, characterization and evaluation data should be available. Definition of terms Characterization consists of recording those characters or traits which are highly heritable or can be easily seen and expressed in all environments. Preliminary evaluation consists of recording of a limited number of additional traits thought desirable by a consensus of users of a particular crop. Characterization and preliminary evaluation are usually done during the initial seed increase. They are normally carried out by the curators. Further characterization and evaluation are the responsibility of the breeder and specialists (e.g., entomologist for insect resistance, physiologist for stress tolerance, pathologist for disease resistance). However, the information obtained should be supplied to the curators who should be maintaining the database.

42 Descriptors and descriptor states

Germplasm collection, evaluation,

In characterization and evaluation, a descriptor list is used. A descriptor is an identifiable and measurable trait or characteristic of a plant accession (e.g., height, color) used to make classification, storage, retrieval, and use more uniform (IBPGR 1991). A descriptor list is a collation of all the individual descriptors used for a particular species (IBPGR 1991). Several important species have a standardized descriptor list published by the International Board for Plant Genetic Resources. If the descriptor list is prepared following prescribed global standard, then this becomes a universally understood vehicle of genetic information storage and retrieval. Based on IBPGR guidelines, the following are the internationally accepted norms for the scoring or coding of descriptor states. 1. Measurements are made in metric units. 2. Many descriptors which are continuously variable are recorded on a 1—9 scale. Modifications may be made such as 3, 5, 7 for describing only a selection of the states. 3. Presence or absence of characters are scored as 1 = present and 0 = absent. 4. For descriptors which generally are not uniform throughout the accession (e.g., genetic segregation, mixtures), mean and standard deviation could be reported where the descriptor is continuous or mean and "X" where the descriptor is continuous. 5. Where the information does not exist (descriptor is not applicable), "0" is used. 6. Blanks are used for information not yet available. 7. Standard color charts (e.g., Royal Horticultural Society Color Chart, Methuen Handbook of Color, Munsell Color Chart for Plant Tissues) are strongly recommended for all ungraded color characters. The precise chart used should be specified in the "Notes" Descriptor. If a standardized descriptor list is not available, one can construct a descriptor list. The following is a general procedure in constructing a descriptor list. 1. Assemble all published taxonomic descriptions used for the species. When gathering the information consider all the taxonomic names to which the species has been referred to in literature (e.g., synonyms). Consider also related taxa. 2. Analyze the descriptions for any pattern of variation that is recognizable. Take note if differences are obvious. Note also if the character is heritable or environmentally influenced. 3. List the morphological characters that should be included in the descriptor list. 4. Assemble a collection of accessions or make field collections from where you can directly observe the different states for each morphological trait.

documentation, and conservation 5. Prepare a preliminary descriptor list.

43

6. Test the descriptor list by going through each accession / collection and scoring them objectively using the preliminary descriptor list. 7. Revise the list if necessary. Examples of characterization data sheets used at the Genetic Resources and Seed Unit of AVRDC are included in this lecture material. References IBPGR. 1991. Elsevier's Dictionary of Plant Genetic Resources. Elsevier, Amsterdam, New York, Tokyo, Oxford.

44

Germplasm collection, evaluation, AVRDC-GRSU CHARACTERIZATION RECORD SHEET
Crop: Sowing date Transplanting date Location EGGPLANT Accession no. Plot no. Name Species Origin

SEEDLING DATA 5110 S120 S130 S140 5150 Germination period (no. of days from sowing till first germination) Cotyledonous leaf length (mm) (N=10) Cotyledonous leaf width (nun) (N=10) Cotyledonous leaf color 5 = Light violet 3 = Green Cotyledon length/width ratio 3 = Low (-2.2) 1 = Very low (<2.0) 9 = Very high (>5.0) 7 = High (-3.5)

7 = Violet 5 = Intermediate (-2.5) X = Mixture

X = Mixture

VEGETATIVE DATA S210 S220 Plant growth habit 3 = Upright 5 = Intermediate 7 = Prostrate 5 = Intermediate (-60) X = Mixture 5 = Intermediate X = Mixture X = Mixture

Plant height (cm) (at flowering stage) 3 = Short (-30) 1 = Very short (<20) 9 = Very tall (>150) 7 = Tall (-100) Plant breadth (cm) (at flowering stage) 1 = Very narrow (<30) 3 = Narrow (-40) 9 = Very strong (>130) 7 = Broad (-90)

S230

S240

Plant branching (no. of primary branches per plant) 5 = Intermediate (-10) 3 = Weak (-5) 1 = Very weak (-2) X = Mixture 9 = Very strong (>30) 7 = Strong (-20) Petiole color 1 = Green 7 = Dark violet Petiole length (mm) 0 = None 5 = Intermediate (-30) 2 = Greenish violet 9 = Dark brown 1 = Very short (<5) 7 = Long (-50) 3 = Violet X = Mixture 3 = Short (-10) 9 = Very long (>100)

S250

S260

X = Mixture

documentation, and conservation
Crop: Location S270 S280 S290 Leaf blade length (cm) 3 = Short (-10) EGGPLANT Acc. no. Plot no. 7 = Long (-30) 7 = Wide (-15) 5 = Intermediate X = Mixture X = Mixture 7 = Strong

45

5 = Intermediate (-20)

Leaf blade width (cm) (maximum width) 3 = Narrow (-5) 5 = Intermediate (-10) Leaf blade lobing 1 = Very weak 9 = Very strong Leaf blade tip angle 1 = Very acute (<15°) 7 = Obtuse (-110°) 3 = Weak X = Mixture 3 = Acute (-45°) 9 = Very obtuse (>160°)

S300

5 = Intermediate (-75°) X = Mixture 5 = Dark green X = Mixture

S310

Leaf blade color (upper surface) 1 = Light green 3 = Green 7 = Greenish violet 9 = Violet

S320

Leaf prickles (no. of leaf prickles on upper surface of the leaf) 1 = Very few (1-2) 3 = Few (3-5) 0 = None 5 = Intermediate (6-10) 7 = Many (11-20) 9 = Very many (>20)

X = Mixture

S330

Leaf hairs (no. of hair per mm 2 on lower surface of the leaf) 1 = Very few (<20) 3 = Few (20-50) 5 = Intermediate (50-100) 7 = Many (100-200) 9 = Very many (>200) X = Mixture

INFLORESCENCE DATA S410 S420 S430 Number of flowers per inflorescence Flowering time (no. of days from sowing till first flower opening) Number of hermaphrodite flowers per inflorescence 1 = Only one hermaphrodite flower on each inflorescence 2 = Only two hermaphrodite flower on each inflorescence 3 = Only three hermaphrodite flower on each inflorescence 4 = Four or more hermaphrodite flower on each inflorescence, but some flowers functionally male 5 = Four or more hermaphrodite flower on each inflorescence, no functionally male flowers X = Mixture Corolla color 1 = Greenish white 7 = Light violet 3 = White 9 = Bluish violet 5 = Pale violet X = Mixture 7 = Long (-5) 7 = High X = Mixture X = Mixture

S440

S450 S460

Relative style length (mm) 5 = Intermediate (-3) 3 = Short (-1) Pollen production 3 = Low 0 = None 5 = Medium

46 Crop: Location

Germplasm collection, evaluation,
EGGPLANT Acc. no. Plot no.

FRUIT DATA First harvest date Last harvest date Fruiting date (date when 50%, of plants have mature fruits) 5510 Fruit length (cm) (from base of calyx to tip of fruit) 1 = Very short (<1) 3 = Short (–2) 5 = Intermediate (–5) 7 = Long (=10) 9 = Very long (>20) X = Mixture Fruit breadth (cm) (diameter at broadest part) 1 = Very small (<1) 3 = Small (–2) 7 = Large (–5) 9 = Very large (>10)

S520

5 = Intermediate (–3) X = Mixture

S530

Fruit length/breadth ratio 1 = Broader than long 3 = As long as broad 5 = Slightly longer than broad 7 = Twice as long 8 = Three times as long 9 = Several times as long as broad as broad as broad X = Mixture Fruit curvature 1 = None 7 = Snake shape

S540

3 = Slightly curved 9 = U-shaped

5 = Curved X = Mixture

S550

Fruit pedicel length (mm) 1 = Very short (<5) 3 = Short (–10) 7 = Long (–50) 9 = Very long (–75) Fruit pedicel thickness (mm) 1 = Very thin (<1) 3 = Thin (–2) 7 = Thick (–5) 9 = Very thick (>10) Fruit pedicel prickles 0 = None 5 = Intermediate (–10)

5 = Intermediate (–25) X = Mixture

S560

5 = Intermediate (–3) X = Mixture

S570

1 = Very few (<3) 7 = Many (–20)

3 = Few (–5) 9 = Very many (>30) X = Mixture

S580

Fruit shape 3 = About 1/4 way from base to tip 5 = About 1/2 way from base to tip 7 = About 3 /4 way from base to tip X = Mixture Fruit apex shape 3 = Protruded

S590

5 = Rounded

7 = Depressed

X = Mixture

S600

Fruit color at commercial ripeness 1 = Green 2 = Milk white 5 = Scarlet red 6 = Lilac grey 9 = Black X = Mixture

3 = Deep yellow 7 = Purple

4 = Fire red 8 = Purple black

documentation, and conservation
Crop: Location EGGPLANT Acc. no. Plot no.

47

S610

Fruit color distribution at commercial ripeness 1 = Uniform 3 = Mottled X = Mixture Fruit color at physiological ripeness 1 = Green 2 = Deep yellow 5 = Fire red 6 = Poppy red 9 = Black X = Mixture Fruit position 1 = Erect 7 = Semipendant

5 = Netted

7 = Striped

S620

3 = Yellow orange 7 = Scarlet red

4 = Deep orange 8 = Light brown

5630

3 = Semierect 9 = Pendant

5 = Horizontal X = Mixture

S640

Relative fruit calyx length (N=10) 1 = Very short (<10%) 7 = Long (-70%) 3 = Short (-20%) 9 = Very long (>75%) 5 = Intermediate (-50%) X = Mixture

S650

Fruit calyx prickles (N=10) 0 = None 5 = Intermediate (-10) 1 Very few (<3) 7 = Many (-20) 3 = Few (-5) 9 = Very many (>30) X = Mixture

S660

Fruit cross section 1 = Circular, no grooves 3 = Elliptic, no grooves 5 = Few grooves (-4) 7 = Many grooves (-8) 9 = Very irregular X = Mixture Number of locules per fruit (N=10)

S680

S690

Fruit flesh density 1 = Very loose (spongy) 3 = Loose (crumbly) 7 = Dense 9 = Very dense Number of fruit per infructescence Number of fruit per plant Fruit yield per plant (g) 1 = Very low (<250) 3 = Low (-500) 7 = High (-2500) 9 = Very high (>5000) Fruit flavor 3 = Bitter

5 = Average density X = Mixture

S700 S710 S720

5 = Intermediate (-1000) X = Mixture

S730

5 = Intermediate

7 = Sweet

X = Mixture

48
Crop: Location SEED DATA 5810 Seed color 1 = White 2 = Light yellow 4 = Brownish yellow 5 = Brown X = Mixture

Germplasm collection, evaluation,
EGGPLANT Acc. no. Plot no.

3 = Gray yellow 6 = Brown black

4 = Brownish yellow 9 = Black

S820

Number of seeds per fruit 0 = None 1 = Very few (<10) 3 = Few (—50) 7 = Many (—300) 9 = Very many (>500) X = Mixture Seed size (mm) 3 = Small (—2) 100-seed weight (g) 5 = Intermediate (—3) 7 = Large (—4)

5 = Intermediate (—100)

S830 5840

X = Mixture

documentation, and conservation AVRDC-GRSU CHARACTERIZATION RECORD SHEET
Crop: Sowing date Transplanting date Location PEPPER Accession no. Plot no. Name Species Origin

49

SEEDLING DATA C110 Hypocotyl color (terminal bud 1-2 mm) 1 = Green 2 = 1/4 purple from the base 4 = Purple X = Mixture Hypocotyl color intensity 3 = Light 5 = Medium Cotyledonous leaf length (mm) (N=10) Cotyledonous leaf width (mm) (N=10) Cotyledonous leaf shape 3 = Deltoid 5 = Ovate Cotyledonous leaf color 3 = Light green 9 = Other (Specify) Hypocotyl pubescence 0 = Glabrous 3 = Sparse X= Mixture Stem color (before transplanting) 1 = Green 3 = Green with many purple strips 5 = Other (Specify) 7 = Dense 3 = 1/2 purple from the base X = Mixture

C120 C130 C140 C150 C160

7 = Lanceolate 5 = Green X = Mixture 5 = Intermediate

X = Mixture 7 = Dark green

C170

7 = Abundant

C250

2 = Green with few purple strips 4 = Purple X = Mixture

50 Crop: Location

Gennplasm collection, evaluation,
PEPPER Season Acc. no. Plot no.

VEGETATIVE DATA
C210

Plant growth habit 3 = Prostrate

5 = Compact

7 = Erect

X = Mixture

C230

Stem pubescence density (at 2 nodes below the shoot when first fruit turning red), 0 = Glabrous 3 = Sparse 5 = Intermediate 7 = Abundant X = Mixture Stem pubescence type (at 2 nodes below the shoot when first fruit turning red) 0 = Absent 3 = Short 5 = Intermediate 7 = Long X = Mixture Leaf pubescence density (of youngest mature leaf when first fruit turning red) 0 = Glabrous 3 = Sparse 5 = Intermediate 7 = Abundant X = Mixture Leaf pubescence type (of youngest mature leaf when first fruit turning red) 0 = Absent 3 = Short 5 = Intermediate 7 = Long X = Mixture Leaf shape 3 = Deltoid Leaf color 1 = Yellow 5 = Other (specify) 5 = Ovate 2 = Light green 7 = Lanceolate 3 = Green X = Mixture X = Mixture 4 = Dark green

C240

C260

C270

C300

C310

C280

Mature leaf length (cm) (N=10; leaves from main stem) Mature leaf width (cm) (N=10; leaves from main stem) Plant size 3 = Small Plant stature 3 = Short

C290

C360

5 = Intermediate 5 = Intermediate

7 = Large 7 = Tall

X = Mixture X = Mixture

C370

C730

Nodal anthocyanin (whole plant) 0 = Green 3 = Light purple 5 = Purple Leaf pigmentation 0 = Absent Branching habit 0 = None 1 = Present

7 = Dark purple X = Mixture

C320

X = Mixture 5 = Intermediate 7 = Abundant

C330

3 = Sparse

X= Mixture

documentation, and conservation
Crop:
Location

51 PEPPER
Season

Ace. no. Plot no.

INFLORESCENCE DATA C410 Number of pedicels per axil 1 = Only one pedicel per axil 3 = Three or more pedicels per axil X = Mixture Pedicel position at anthesis 3 = Pendant 5 = Intermediate Angle between flower and pedicel 3 = 0° 5 = 45° 7 = 90° Corolla color 1 = White 5 = White with purple base Calyx margin shape 3 = Smooth 2 = Light yellow 6 = White with purple margin 5 = Intermediate

2 = Two pedicels per axil 4 = Many pedicels in bunches but each in individual axil 7 = Erect 9 = >90° 3= Yellow 7 = Purple X = Mixture 7 = Dentate X = Mixture X = Mixture 4 = Yellow-green 8 = Other (specify)

C420 C430 C440

C460 C470

X = Mixture

Annular constriction at junction of calyx and peduncle (at mature green stage) 0 = Absent 3 = Not clear 5 = Clear 7 = Distinct and uniform in the whole plant X = Mixture Corolla spot 0 = Absent 4 = Green 1 = White 2 = Yellow 5 = Other (specify) 3 = Blue X = Mixture 3 = Green 7 = Other (specify) 3 = Green-yellow X = Mixture 4 = Purple

C820

C830

Anther color (immediately after flowering) 1 = Yellow 2 = Pale blue 5 = Other (specify) Filament color 1 = White 5 = Light purple 2 = Yellow 6 = Purple

C840

4 = Blue X = Mixture X = Mixture

C860

Stigma position in relation to anthers at full anthesis 3 = Inserted 5 = Same level 7 = Exserted Flowering date (date when 50% of plants have the most flower)

C810 C450

Days to flower (no. of days from sowing until 50% of plants have the most flowers) Corolla length (nun) (N=10)

52 Crop: Location

Germplasm collection, evaluation,
PEPPER Season Acc. no. Plot no.

FRUIT DATA First harvest date Last harvest date Fruiting date (date when 50% of plants have mature fruits) C900 C910 C930 C920 C940 C640 C630 Fruit length (cm) (N=10, at second harvest ) Fruit width (cm) (N=10, at second harvest) Fruit wall thickness (cm, to one decimal point) (N=10, at second harvest) Fruit weight (g) (N=10, at second harvest) Fruit pedicel length (cm) (N=10; at second harvest) Number of locules Fruit pungency 0 = Not pungent (sweet) 7 = High Soluble solids (%) (N=10) Fruit position 3 = Declining 5 = Intermediate 7 = Erect 3 = Orange 7 = Black X = Mixture 4 = Red

3 = Low X = Mixture

5 = Intermediate

C670 C500 C510

Fruit color at immature stage 2 = Yellow 1 = Green 5 = Purple 6 = Brown X = Mixture 8 = Other (specify) Fruit color intensity at immature stage 5 = Medium 3 = Light

C520 C530

7 = Dense

X = Mixture 5 = Purple X = Mixture

Fruit color at intermediate stage between immature and mature stage 3 = Orange 4 = Red 1 = Green 2 = Yellow 8 = Other (specify) 6 = Brown 7 = Black

documentation, and conservation Acc. no. C540 Fruit color at mature stage 2 = Yellow 1 = Green 6 = Purple 5 = Red 9 = Other (specify) Fruit color intensity at mature stage 3 = Light 5 = Medium Fruit shape 1 = Elongate 5 = Campanulate 2 = Oblate 6 = Bell or blocky Plot no.

53

3 = Orange 7 = Brown X = Mixture 7 = Dense 3 = Round 7 = Other (specify) 5 = Truncate

4 = Orange-red 8 = Black

C550 C570

X = Mixture 4 = Conical X = Mixture 7 = Cordate

C580

Fruit shape at peduncle attachment 1 = Acute 3 = Obtuse 9 = Lobate X = Mixture Neck at base of fruit 0 = Absent Fruit shape at blossom end 3 = Pointed 5 = Blunt Fruit blossom end appendage 0 = Absent 1 = Present

C590 C600 C650 C610 C620

1 = Present 7 = Sunken X = Mixture

X = Mixture X = Mixture

Fruit cross-sectional corrugation (1 /3 from pedicel end) 0 = Smooth 3 = Slightly corrugated' 5 = Intermediate 7 = Corrugated X = Mixture Fruit persistence 0 = Deciduous (only pedicel and calyx remain on plant) 3 = Slight 5 = Intermediate 7 = Persistent Duration to fruiting 3 = Early Fruit set 3 = Low 5 = Intermediate 5 = Intermediate 7 = Late 7 = High 5 = Medium mixture X = Mixture X = Mixture 7 = Serious mixture

X = Mixture

C880 C890 C660 C950

Varietal mixture condition 0 = Pure 3 = Slight mixture Anthocyanin spots in unripe stage 0 = Absent 1 = Present

SEED DATA C960 C990 Seed color 1 = Straw 2 = Black/Brown 3 = Other (specify) X = Mixture

Number of seeds per fruit 0 = No seed 3 = Few

5 = Some

7 = Many

X = Mixture

54

Germplasm collection, evaluation, AVRDC&GRSU CHARACTERIZATION RECORD SHEET
Crop: Origin Sowing date Location SOYBEAN Accession no. Plot no. Name Species

SEEDLING DATA G081 Hypocotyl color Recorded at the time when the primary leaves are expanded 1 = Green 2 = Purple

VEGETATIVE DATA G021 G031 G091 Stem determination 3 = Determinate Number of leaflets 1=3 5 = Semideterminate 5=4-6 7 = Indeterminate 7 = 7 or more

Leaflet size Recorded with length (cm) x width (cm) 3 = Small (70 cm2 or less) 7 = Large (150 cm 2 and more)

5 = Medium (71 to 149 cm 2 )

G041

Leaflet shape 3 = Narrow (1/w 2.2 or more) = 'lanceolate' 5 = Intermediate (1/w 1.9.2.1) 7 = Broad (1/w 1.8 or less) = 'ovate' Pubescence density 0 = Absent 3 = Sparse Pubescence color 1 = Gray 5 = Semisparse 7 = Normal 9 = Dense

G051 G061 G071

2 = Light brown

3 = Brown = 'tawny' 4 = Curly 5 = Retrorse tip

Pubescence type 1 = Erect 2 = Semiappressed 3 = Appressed

documentation, and conservation
Crop: Location G111 SOYBEAN Acc. no. Plot no.

55

Plant height at R1 Actual measurement in cm as mean of 20 randomly selected plants

G141

Plant height at Rg Actual measurement in cm as mean of 20 randomly selected plants

G151

Number of primary branches (when at least 2 nodes) per plant at maturity Mean of 20 randomly selected plants

G161

Lodging score Scored from leaning angle and lodging area (see table 1) 0 = None 3 = Slight 7 = Severe 5 = Moderate Table 1. Leaning angle and lodging area Lodging area 0-9° 10-19° 0-19% 1 1 20-39% 1 1 40-59% 1 3 60-79% 1 3 80% 3 3 20-29° 1 3 3 5 5 40-49° 1 3 5 7 7

9 = Very severe 60° 1 5 7 9 9

INFLORESCENCE DATA G221 G201 G211 G241 Days to flowering (R1) Number of days from planting to 50% of plants with at least one open flower Corolla color 3 = White Mature pod color 3 = Tan 5 = Purple throat 5 = Brown 7 = Purple 7 = Black

Number of pods per plant (Mean of 20 randomly selected plants)

G381

Number of seeds per pod (Mean of 20 randomly selected pods)

G231

Shattering score Estimated percent of pod splitting and seed shattering at a comparable time after maturity 1 = No shattering 2 = Slight shattering 5 = Medium shattering 7 = Shattering 9 = Highly shattering

56 Crop: Location SEED DATA G391 G301 Hard seeds (actual percent) Seed color 1 = Yellowish white 5 = Brown 8 = Black Seed coat pattern 1 = Light hilum 2 = Yellow 6 = Gray 9 = Others (specify) 2 = Dark hilum

Germplasm collection, evaluation,
SOYBEAN Ace no. Plot no.

3 = Green 4 = Light brown 7 = Imperfect black (black shading to buff) 3 = Saddle 4 = Green 7 = Black 4 = Striped 5 = Gray 8 = Others (specify) 9 = Heavy bloom

G311 G321

I-hlum color 1 = Yellow 2 = Buff 3 = Brown 6 = Imperfect black (= black with buff outer ring) Seed coat surface luster 3 = Shiny 5 = Intermediate 7 = Dull

G331 G341 G351 G411 G421

100-seed weight (g) Absolute values in g normally measured at 13–15% moisture content Cotyledon color 1 = Yellow Total oil content Percent on dry seed weight basis Protein content (6.25 x N) Percent on dry seed weight basis 2 = Green

documentation, and conservation AVRDC-GRSU CHARACTERIZATION RECORD SHEET
Crop: Sowing date Transplanting date Location TOMATO Accession no. Plot no. Name Species Origin

57

SEEDLING DATA L070 Anthocyanin coloration of hypocotyl (when the seedling primary leaves are fully open and the terminal bud is around 5 mm) 0 = Absent 1 = Present X = Mixture Stem pubescence 0 = Absent 3 = Weak 5 = Medium 7 = Strong

L120 L080 L100

Primary leaf length (mm) (N=10) Primary leaf width (mm) (N=10)

VEGETATIVE DATA L150 L170 L180 L090 Leaf attitude 3 = Semierect 5 = Horizontal 7 = Drooping 7 = High X = Mixture X = Mixture X = Mixture

Degree of leaf dissection 3 = Slight 5 = Medium Anthocyanin coloration of leaf veins 1 = Present 0 = Absent

Growth habit (when the fruits of first truss ripen) 1 = Dwarf 2 = Determinate 3 = Semideterminate 4 = Indeterminate X = Mixture Location Acc. no. Plot no.

L130 L160

Number of leaves under first inflorescence (N=5) Leaf type

58 Location Acc. no. INFLORESCENCE DATA

Gennplasm collection, evaluation,
Plot no.

Flowering date (date when 50% of plants have the most flowers) L210 L230 L300 L270 L280 L290 Days to flower Inflorescence type (information should be taken from the 2nd and 3rd truss) 1 = Generally 2 = Generally multiparous 3 = Both Stamen length (cm) (N=5) Petal length (cm) (N=5) Sepal length (cm) (N=5) Style type 1 = Inserted 7 = Highly exserted

3 = Same level as stamen X = Mixture

5 = Slightly exserted

L200

Number of flower per inflorescence (N=5)

FRUIT DATA First harvest date Last harvest date Fruiting date (date when 50% of plants have mature fruits) L610 L340 L350 L470 Days to fruit Exterior color of immature fruit 3 = Light 5 = Medium Intensity of greenback 0 = None 3 = Slight

7 = Dark 5 = Medium

9 = Very dark 7 = Strong

X = Mixture X = Mixture

Number of fruit set per inflorescence (2nd truss) (N=5)

-aluat..ion,

documentation, and conservation
Location ACC. no.
L730

59
Plot no.

Size of core (in cross-section) (mm) (N=10) Thickness of pericarp (mm) (N=10)

L720

L880 L950

Soluble solids (Brix) Length of pedicel scar (mm) (N=10) Number of locules (N=10) Size of pedicel scar width (mm) (N=10) Size of corky area around pedicel scar (mm) (N=10) Fruit length (cm) (N=10) Fruit width (cm) (N=10) Pedicel length (measured from abscission layer to calyx) (mm) (N=10) Thickness of fruit wall (mm) (N=10) Shape of pistil scar 1 = Dot 2 = Stellate Blossom end shape 1 = Indented 2 = Flat

L710

L760

L770

L490

L500

L740

L510

L780

cture
L790

3 = Linear

4 = Irregular 3 = Pointed

X = Mixture X = Mixture

,ture

60
Location Acc. no. L800 L810 L820 L530 L520 Blossom end scar condition 1 = Open 2 = Closed Puffiness 3 = Slight Easiness of peeling 3 = Poor 5 = Medium 5 = Fair

Germplasm collection, evaluation,
Plot no.

3 = Both 7 = Severe 7 = Good 7 = Severe 3 = Orange X = Mixture X = Mixture X = Mixture 4 = Red

Vascular bundle content 3 = Slight 5 = Medium Exterior color of mature fruit 1 = Green 2 = Yellow 5 = Pink X = Mixture Fruit weight (g) (N=10) Color of core 0 = Green 7 = Dark 1 = White X = Mixture

L480 L700

3 = Light

5 = Medium

L360 L370

Skin color of ripe fruit (observe the peeled fruit skin) 1 = Colorless 2 = Yellow X = Mixture Interior flesh color (pericarp) 1 = Green 2 = Yellow 5 = Pink 6 = Others Interior flesh color intensity 3 = Light 5 = Medium Transverse section 1 = Round 2 = Angular 3 = Orange 4 = Red X = Mixture X = Mixture X = Mixture

L380 L390 L400

7 = Dark 3 = Irregular X = Mixture

Presence of jointless pedicel 0 = Absent 1 = Present

documentation, and conservation
Location Acc. no. Plot no.

61

L410

Ribbing at calyx end 0 = Absent 3 = Slight Firmness 3 = Soft

5 = Medium

7 = Strong

X = Mixture

L430

5 = Medium

7 = Firm

X = Mixture

L330

Predominant fruit shape (after the fruits turn color) 1 = Flattened 2 = Slightly flattened 3 = Round 4 = High-round 5 = Heart-shaped 6 = Lengthened cylindrical 7 = Pear-shaped 8 = Plum-shaped X = Mixture Fruit size variation within a plant 1 = Uniform 3 = Slight Fruit fasciation 1 = Smooth

L320

5 = Medium

7 = High

L460

3 = Slight

5 = Medium

7 = Severe

X = Mixture

L440

Radial cracking (environmental dependent) 0 = None 1 = Corky lines 5 = Medium 7 = Severe

3 = Slight X = Mixture

L450

Concentric cracking (environmental dependent) 0 = None 2 = Corky lines 3 = Slight 7 = Severe X = Mixture Pedicel area 1 = Flat 3 = Slightly depressed 7 = Strongly depressed

5 = Medium

L750

5 = Moderately depressed X = Mixture

62

Germplasin collection, evaluation,

7

Techniques Handling Vegetable Seeds

Storing

M.L. Chadha

Senior Horticulturist/Agronomist BARC/BARI and AVRDC Project, BARI Joydebpur, Gazipur-1701, Bangladesh
Vegetables not only improve the quality of our diet but also provide essential ingredients like vitamins, minerals, and carbohydrates. They can generate employment in the rural areas. Because of high productivity, they provide better economic returns per unit area and are potential foreign exchange earners. In developing countries, due to malnutrition and particularly deficiency of vitamin A, children suffer from blindness. Vegetables should, therefore, form an integral part of the diet. The seed is the basic input and a primary requisite for successful vegetable growing. In the production of most vegetable crops, the seed is an insignificant item in the total cost of production. But with the use of poor seeds, investment in major inputs like fertilizers, water, and plant-protection chemicals, will not pay the dividends which ought to be obtained. A good quality seed with high viability and vigor contributes nearly 30% to total production. Thus, proper handling and storage of seed is essential during vegetable production. A good vegetable seed should be: (1) viable, (2) clean, (3) free from diseases, and (4) genetically pure. Information about the germination capacity of seeds helps the grower in working out the seed rate to be used. The minimum percentage of germination to be expected in the case of a normal and healthy seed can be determined from fixed standards (Table 1). Freedom from foreign matter can be ensured by proper cleaning. Some diseases of vegetable crops can be safely controlled by treating the seeds with fungicides before sowing.

documentation, and conservation Table 1. Standards of minimum germination for vegetable seed
Vegetable 1. Alliums leek onion Welsh onion 2. Crucifers broccoli cauliflower Chinese cabbage (heading) Chinese cabbage (nonheading) common cabbage kale mustard
radish

63

Germination % 70 75 75 75 75
75 75

Vegetable watermelon (seedless) wax gourd 4. Leguminous vegetables broad bean lima bean pea snap (French) bean yard-long bean 5. Solanaceous vegetables eggplant pepper (sweet, hot)
tomato

Germination % 60 70 75 75 75 75 75 65 65 75 70 70 80 75 75 70 75 70 60

75 75
75 75

turnip 3. Cucurbits bitter gourd bottle gourd
cucumber

80 65 80
80

melon luffa gourd pumpkin squash watermelon

80 75 80 80 80

6. Other tropical vegetables amaranth kangkong okra sweet corn 7. Other cool-season vegetables asparagus celery coriander lettuce spinach

The most difficult problem faced by the vegetable growers today is how to ensure the genetic purity of the seed. What is trueness to type and how to get it is the everyday question asked by the growers. To understand the meaning of trueness to type, it is pertinent to know the following terms used in the seed industry. Kind — includes all the plants which, in general use are accepted as a single vegetable, e.g., watermelon, tomato, 'bhindi', etc. Variety — includes those plants of a given kind which are practically alike in their important characteristics of plant and product. For example, Manik is a variety of tomato and Uttara is a variety of brinjal. Strain — includes those plants of a standard variety, which possess the general characteristics of the mother variety, but differ in one important or two to three minor aspects. For example, Ratan is a standard variety of tomato and Agro Service has selected certain plants and multiplied the variety as Agro Ratan. Stock — represents all plants of the same parentage. A slight difference may come about during maintenance. For example, the Manik variety of tomato was released by BARI. They gave the stock seed to the Bangladesh Agricultural Development Corporation

64

Germplasm collection, evaluation,

(BADC) and other agencies for further multiplication. The same seed. handled by different people may be called different stocks. The production of vegetable seed is very similar to the general cultivation of a crop. However, certain aspects are significantly different and thus make seed production a highly specialized enterprise. Several factors are associated with seed deterioration. Preharvest factors Apart from the inheritance nature of seed viability, environmental factors such as climate, nutrition, and water supply are liable to change seed characteristics. Deficiencies in nitrogen, potassium, and calcium significantly affect the storability of seed. The position of the seed on the mother plant and the stage at which the physiological ripening processes end are even more important. In okra, selection of basal 3-4 pods are ideal for obtaining good quality seed. In cucurbits, the seeds nearer to the basal end are more vigorous during subsequent sowing. Tomato seeds extracted at breaker stage are viable and can be harvested at this stage as protection from natural pests or diseases. However, seed harvested at the ripe stage retains viability for longer periods. In general, seeds are harvested when they attain physiological maturity and at this stage deterioration of vitality begins. Thus, care should be taken to avoid mechanical injury during the harvesting, which permits the entry of moisture and microorganisms. Each crop has its optimum moisture content for low levels of mechanical injury and processing. In general, 14-16% of moisture content is desirable during harvesting. The quality of the seedlot can be improved by cleaning, grading, and other processing operations. Seed cleaning Seed cleaning includes the removal of contaminations from the seed such as . chaffs, stems, and stones. Other crop seed and seed may be much more difficult to remove, especially those which are similar in appearance and physical characteristics. In seed processing, these are cleaned by mechanical devices using certain physical characteristics such as size, length, shape, density, surface texture, and electrical properties. Seed drying Seed moisture plays an important role in seed deterioration. During seed development, maturation, and ripening of seed, moisture content gradually decreases till harvesting, where it attains equilibrium with the atmospheric humidity. Further, it changes with increase or decrease of relative humidity and temperature of air or both. The moisture equilibrium varies with the cultivars and with the chemical composition of seed. During drying, the water evaporates from the seed into the atmosphere, and a moisture gradient is set up inside the seed that causes internal moisture to move towards the surface. If the

I

documentation, and conservation

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rate of evaporation is high, then it is likely to damage the embryo and result in loss of viability. Several methods are being used for drying the seeds: natural drying, sun drying, unheated, heated and dehumidified air drying with desiccants, vacuum drying, and freeze drying. Each has its own advantages and disadvantages. However, seed should be protected from excessive heat damage during drying. Most of the vegetable seeds are dried to 6 – 7% moisture and those seeds rich in oil content are dried to 5% moisture as in:
Crop Bean Beet Brinjal Cabbage Carrot Cauliflower Cowpea Muskmelon Moisture content (%) 7.0 7.5 6.0 5.0 7.0 5.0 7.0 6.0 Crop Onion Okra Pea Pepper Pumpkin Radish Tomato Watermelon Moisture content (%) 6.5 6.0 7.5 5.0 6.0 5.0 5.5 6.5

Seed storage The longevity of a seed is genetically predetermined. The occurrence of different climatic conditions and pests and diseases shorten storage life. In storage, seeds are protected from high temperature and high relative humidity so that deterioration processes are slowed down. Storage requirement varies with the different users. Farmers like to store seeds till the next growing season. The seed dealer wants to sell viable seed while the research worker needs to keep the seed for several years to preserve valuable genetic material. All mankind is concerned with seed longevity since the genetic material conserved in the seedbank may be essential to our survival in the changing ecology of this world in the future. In tropical climates where both temperature and humidity are high, seed storage often presents problems not encountered in temperate conditions. Seed factors Seed storage begins immediately after maturity regardless of where or how seeds are held. Longevity of seeds varies with species and genotypes. It is short-lived in onion, French bean, cowpea, and capsicum. In general, healthy, plump, and well-matured seed stores better than immature seed. In French bean, medium to large seed exhibits higher longevity and also early emergence and better establishment of seedling in the field. The length of time for which a seed retains its viability depends on a number of factors, namely the kind of seed, proper maturity, and curing to a low moisture content and the storage conditions. The important vegetable crops can be grouped according to the length of time in which they remain viable (Table 2).

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Germplasm collection, evaluation, Table 2. Longevity of seeds of important vegetable crops
Group I II III IV Name of crop Onion Beans, carrot, bhindi, and chili Radish, Linda, luffa, gourds, and peas Caulifower, cabbage, tomato, brinjal spinach, muskmelon, and watermelon Length of time in which seeds retain viability 1 year 2 years 3 years 4—5 years

Grouping according to longevity can be a good basis for determining the suitability of the seed or its use.

Seed environment The storage requirement for viability maintenance varies for different types of seed. Seed moisture, storage temperature, and oxygen are important factors to consider in maintaining seed. At high moisture and temperature, the metabolic activity and incidence of pests and diseases increase, resulting in death of the seed. Under ideal storage Conditions both relative humidity and temperature are kept low. The higher the moisture content of the seed the more they are adversely affected by temperature. Low temperature and seed moisture content, therefore, are needed to maintain seed quality during storage. It is believed that the life of the seed is halved for every 5°C increase in storage temperature and for every 1% increase in seed moisture. This is true between 514% moisture and 0-50°C. Storage containers Preserving seed in a suitable container prevents the direct contact of seeds with the environment. This is another approach for retaining viability. Different containers like paper, cloth, metal, polyethylene, glass, and laminated foils are commonly used for storage. These are selected according to kind and amount of seeds to be stored, duration of storage, etc. Paper and cloth bags are less expensive and can be used for short-term storage. Glass, metal, and laminated foils are moisture-proof and used for long-term storage. Singh and Singh (1989) reported that onion seed with 4.1% moisture content stored longer in sealed glass bottles (23 months) than in one to three layers of polythene (700 guage) (20 months) and cotton cloth bags (16 months) under ambient conditions. Sealed glass bottles are best for storage of onion seed, followed by polythene films. Different layers of polythene have no observed effect on onion seed. Storage fungi The storage fungi are comprised mainly of Aspergillus and Penicillii.an species which affect seed longevity. These fungi grow successfully at moisture content equivalent to 85% and above relative humidity. They reduce seed germination, cause discoloration, and produce mycotoxins resulting in heating and total decay of seed. Application of fungicides prevents the attack of storage fungi. However, no chemical treatment is needed under low moisture and low temperature storage.

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Among many physiological manifestations of seed deterioration are changes in seed color, delayed germination, decreased tolerance to suboptimal environmental conditions during germination and storage conditions, reduced germinability and seedling growth, and increase in the number of abnormal seedlings. Biochemical changes that occur during deterioration are: (1) increase or decrease in enzyme activity, (2) decrease in oxygen uptake, (3) increase in leaching of organic and inorganic constituents from seed, (4) increase in free fatty acid, (5) decrease in total soluble sugars, (6) increase in reducing sugars and decrease in total soluble sugars, (7) decrease in protein and increase in amino acid, and (8) changes in carbohydrates, fatty acid, and protein metabolism. Storage methods Seed moisture and storage temperature play a major role in seed deterioration. Hence, control of these two factors considerably increases storage life. The following methods are useful for increasing seed longevity, depending upon the nature and duration of preservation. Storage with desiccant. This is useful for short-term preservation. Seeds are stored in a jar or suitable container along with a chemical desiccant like silica gel or calcium chloride. These chemicals are inexpensive and easily available and extend seed longevity through reduction in seed moisture. Sealed storage. Well dried seeds are stored in polyethylene, laminates, metal or glass containers and sealed hermetically. This maintains safe moisture level during storage. Such types of packets are commonly observed in the seed market. In long-term preservation such moisture-proof containers are hermetically sealed and stored at low temperature. Cold storage. This is widely used for short-, medium- and long-term preservation of seed at different storage temperatures. Seeds are stored at 20°C, 5°C, and -18°C depending upon duration of storage. Humidity is lowered at nonfreezing temperatures for longer storage. It is essential to store the dry seed at very low temperature, otherwise freezing of moisture kills the seeds. Even at freezing temperature, moisture-proof containers such as metal can, glass, and laminates are used. At very low temperature (-18°C), seed life will be preserved for several years. In several genebanks, seeds are stored at -18°C for conservation of genetic wealth. Vacuum storage. Many times refrigeration facilities are not available. Under such circumstances seed can be stored under vacuum or with inert gases such as nitrogen, carbon dioxide, and others for preservation. Here, the respiration rate is minimum in the absence of oxygen and thus, helps in extending storage life. This method has practical implications under uncontrolled conditions.

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More time is needed to evolve suitable technology for storage using antioxidants, fermentation inhibitors, and organic solvents. During seed deterioration, enzyme activity decreases and certain toxic substances accumulate during metabolic processes, which affect seed germination. Hydrationdehydration during mid-storage is quite useful in removing these substances and restoring viability and vigor. Seeds need to be handled very carefully to avoid injury during harvesting and processing. Further, these should be dried and preserved based on individual requirement to obtain healthy and vigorous seedlings in subsequent sowing. References Doijoide, S.D. 1985. Handling and storage of vegetable seeds. Subject Matter Specialist Workshop. Trainer's Training Center, IIHR, Bangalore, India. Harrington, J.F. and Douglas, J.E. 1970. Seed Storage and Packaging. National Seeds Corporation Ltd. Justice, O.L. and Bass, L.N. 1978. Principles and Practices of Seed Storage. USDA, Washington, USA. Roberts, E.H. 1974. Viability of Seeds. Chapman and Hall Ltd. London. Singh, H. and Singh, G. 1989. Germination of onion seed stored in different containers. The Punjab Vegetable Grower. Vol. XXIV: 4-7. Thomson, J.R. 1979. An Introduction to Seed Technology. Leonard Hill, London.

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8

Germplasm Evaluation

Utilization

J.M. Poulos Associate Plant Breeder AVRDC Shanhua, Tainan, Taiwan, ROC Introduction Plant germplasm collections serve as a major source of plant genetic diversity from which crop improvements are derived. Besides the collection, characterization and storage of plant germplasm for the knowledge of and preservation of plant species, genetic resources must be evaluated and distributed for utilization by the global community. Plant breeders are often the primary users of germplasm collections because they are continually searching for novel traits that may be incorporated into new varieties. It is a major task, however, to search for unique genetic traits that will provide the future breakthroughs for agricultural andindustrial use of plant germplasm resources. Some of the limitations faced by the user community arise from difficulties in accessing germplasm collections, expense, training, dearth in known material with desirable traits, and absence of or nonstandard characterization and preliminary evaluation data. Over the past two decades, international and national germplasm centers have made significant contributions towards improving the quality and distribution of plant genetic resources, although more fundinghasbeen devoted to collection and conservation in comparison to characterization and evaluation activities. It is also the responsibility of the germplasm user community to provide feedback on germplasm evaluation and utilization to the genebank documentation centers.

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Germplasm collection, evaluation,

Plant germplasm evaluation is the next step in documentation after germplasm characterization and maintenance. Plant breeders can make very little use of large germplasm collections if the accessions are not evaluated in some meaningful way. Evaluation of plant genetic resources becomes a multidisciplinary responsibility to compile the best genetic, physiological, and agronomic descriptions for any particular plant accession. Users of plant germplasm want to know the favorable as well as undesirable traits associated with any particular accession to properly manage selection and breeding strategies for its utilization. The major difference between characterization data and evaluation data is that characterization data is based primarily on plant descriptors of highly heritable and easily observed traits, whereas, evaluation data is based primarily on traits related to survival, adaptation, productivity, and quality. Characters for evaluation can often be grouped into both qualitative observable traits or quantitative nonobservable traits. The usefulness of certain kinds of data must be considered before major efforts are launched into the recordkeeping. Yield data is a less useful criterion unless the accessions are evaluated at many locations for many years, or else for specifically defined ecosystems. Many less cultivated, unadapted, or wild species may have valuable genes that contribute to yield, but the potential of these 'yield genes' may be left unnoticed until crosses are made with more cultivated types. This may be true also for other 'hidden' traits. On the other hand direct evaluation data regarding abiotic or biotic stress resistance may be quite meaningful with the expectation that relevant genes could be transferred to advanced breeding lines. Certain procedures should be considered for germplasm evaluation. Evaluation data is most meaningful when it is based on a set of standards. Local as well as universal check varieties should be included in any evaluation to set standards for comparison. Screening methodologies should be well described and repeatable for each batch of accessions that is evaluated. The same scale should be used for rating any particular trait. In practice, four types of scales are used for measurement data. These are (1) internal or direct measurement (e.g., days to flowering), (2) ratio (e.g., harvest index), (3) ordinal (e.g., disease index), and (4) nominal (e.g., categories for qualitative traits). Where disease and pest resistance are being evaluated it is important that the strains, races, or biotypes are referenced with each evaluation, because there are many examples of race-specific types of resistance that are often overcome by other 'races' with different genetic composition. One should be reminded that resistance in tomatoes to strain 'X' of virus 'A' in Bangladesh may not be a useful form of resistance to strain 'Y' of virus 'A'in the Philippines. These biological realities could limit the utilization of particular germplasm, but the ideal situation is to know enough about the germplasm beforehand by testing with a global collection of pathogenic races, biotypes, etc. Because of certain quarantine restrictions on the transport of alien pathogens, this kind of undertaking requires the services of global repositories that have the facilities to manage screening tests with an array of pathogenic strains.

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Some persons might argue that germplasm evaluation should be conducted only in areas where the germplasm is adapted. This may be practical for certain traits but would require global cooperation. Evaluation for 'adaptation' in one area may not be useful information unless climatic and edaphic records accompany the evaluation data. Evaluation for pest and disease resistance may be more efficiently carried out under controlled laboratory or greenhouse conditions because the other environmental factors can be eliminated. If 'Accession A' is field evaluated in acid soils and fails to survive before fruit set, we can learn nothing about: its resistance to fruitworm! Due to the overwhelming size and redundancy of many germplasm collections, the concept of core collections had been instituted to serve as a minimal set of accessions that represent the widest possible range in genetic variability for any particular genus. These core collections can then serve as. the starting point for systematic screening and evaluation. Germplasm utilization Germplasm utilization may be influenced by several factors including food production and agroindustrial demands and constraints, breeding objectives and strategies, availability and usefulness of genetic resources, personnel and material resources, human creativity, and level of interdisciplinary research support. Effective germplasm utilization is a challenge for most plant breeders. Good traits must be selected for while undesirable traits must be selected against. In other cases, germplasm which gives a favorable performance in one location may be directly released as a variety in another location. In the case of less adapted or wild species 'prebreeding' or germplasm enhancement may be done to introgress specific traits into cultivated backgrounds that can be adopted readily for varietal development programs. The 'prebreeding' phase can take many years in itself, particularly if undesirable linkages are associated with the particular trait. Applications in biotechnology may help to minimize these constraints. Sources of germplasm may come from centers of diversity, centers of cultivation or plant breeding programs. Centers of diversity provide primitive cultivars, natural hybrids between related species, wild relatives and related genera. Centers of cultivation provide commercial types with high levels of productivity, obsolete varieties, minor crops, and special purpose types. Breeding programs may provide purelines from farmers' varieties, elite varieties or hybrids, breeding lines, populations, mutants, polyploids, aneuploids, intergeneric and interspecific crosses, and sources of cytoplasmic traits. Germplasm pools are often an effective way of utilizing large numbers of germplasm sources. They must be managed best to maintain a high frequency of 'good' genes compared to undesirable ones. The following is a discussion on the utilization of genetic resources to create germplasm pools for population improvement. Let's begin with a brief introduction of terminology. 'Germplasm' may be considered as a diverse group of plant material that serves as a basis for crop improvement. A plant breeder considers 'germplasm' as a reservoir of genes to

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meet continual challenges for crop productivity. In a broad sense, germplasm is the total of all genotypes present in a species. A 'germplasm pool' is a mixture of more than two sources of germplasm that are intermated in a random mating population. The germplasm pool will usually be more genetically diverse than any one germplasm source, but a germplasm pool usually represents a certain criterion subdivision. For example, germplasm pools may be based on maturity groups, climatic adaptation (tropical, subtropical, highlands, temperature), quality traits (texture, color, vitamin content, soluble solids, pungency), disease or pest resistance. Plant breeders will often create germplasm pools but remnant seed of germplasm sources should still be maintained in genebanks for long-term preservation. Some disadvantages of developing germplasm pools may occur because after intercrossing, some recessive genes may be masked, the frequency of certain alleles may be diluted due to genetic drift, and quantitative traits may be lost due to recombinations that break up desirable groups of alleles. Some alternative strategies for managing germplasm could be to backcross the germplasm to already adapted or commercial material, by which only specific traits are introduced from the germplasm source. Many breeders would choose to use a backcross methodology during initial stages to introduce a desirable trait from an u readapted variety into an already adapted variety. Unfortunately, the more 'wild' the germplasm is there is often the possibility of an adverse linkage between the desirable and undesirable trait. Another option is to maintain the germplasm as an individual. However, this may have several drawbacks, including the overwhelming number of sources that could be handled individually, the possibility that the genetic base of the germplasm is too narrow (limits progress from selection), or the minimal opportunity for genetic recombination (particularly for self-pollinated species). There are two major considerations for the development of germplasm pools. These are the amounts of genetic diversity between and within the germplasm pools. Although one might think it interesting to pool germplasm from diverse origins this could potentially limit the chances for heterosis between germplasm pools because the parents may become too similar after random mating (remember heterosis = dy e 'where d = level of dominance and y = difference in gene frequency between the parents that make the hybrid). At the same time there must still be a fair amount of genetic diversity within the germplasm pool to have a population to select from. The table below compares certain considerations regarding the degree of genetic diversity within germplasm pools: Narrow, elite germplasm 1. maintains favorable linkages 2. useful for varietal development 3. selection progress occurs in small increments 4. small populations without drift problems 5. easy to manage many

Few broad, partially exotic germplasm 1. chances for new recombination 2. reservoir of 'new' alleles 3. progress is high initially, but long term to raise gene frequencies 4. large populations to avoid drift 5. difficult to manage many

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Some of the information regarding the germplasm that a breeder may need to compile before creating germplasm pools are: (1) its unique traits as determined by germplasm evaluation, (2) its pedigree or origin, and (3) its combining ability. These features may help to decide which germplasm pool a particular accession belongs to. Accessions with similar pedigree or region of origin may often be put in the same germplasm pool. Accessions with good combining ability may be kept in distinct pools, whereas those with poorer combining ability may be pooled together because they probably share many of the same genes. Examples: Accession A x Accession B
>>>> w>

heterosis »»»»» separate pools

Accession A x Accession C »»»» heterosis »»»»» separate pools Accession B x Accession C
u»u»

no heterosis >>>>>> same pool

'tester population' x Accession A >>>> heterosis » > » separate pools 'tester population' x Accession B >>>> no heterosis »» same pool Creating a germplasm pool As mentioned before a germplasm pool is a mixture of more than two sources of germplasm that are intermated in a random mating population. There are a number of ways to create this random mating population but the key points to remember are to continue intercrossing for three to seven generations and sow equal seed from each resulting cross for the next round of intermating. Diallel mating designs and polycrosses are most commonly used for creating random mating populations. For species that are easily emasculated, pollen parents may be a bulk or composite of all germplasm sources and subsequently pollen is bulked from the F r s of each generation of intercrosses. The seed parents are the individual germplasm sources or F l s from intercrossing which are then emasculated. In theory, there should be no artificial selection during random mating, but in practice some selection is often unavoidable considering time and space requirements. Germplasm pools serve as source populations for selection and various breeding methods practiced by plant breeders. New genotypes can be added to germplasm pools to increase the frequency of certain genes in the population. Lines derived from germplasm pools may be useful breeding lines or inbreds for varietal or hybrid development. References Frankel, O.H. and Hawkes, J.G. (ed.). 1975. Crop Genetic Resources for Today and Tomorrow. Cambridge University Press, London, England. 492 pp. Hawkes, J.G. 1981. Germplasm collection, preservation, and use. pp. 57-84. In Frey, K. J. (ed.). Plant Breeding II. The Iowa State University Press, Ames. USA.

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Hsieh, S.C. (ed.). 1987. Crop exploration and utilization of genetic resources. Proceedings of the international symposium held at Taichung District Agricultural Improvement Station. 6—12 December 1986, Taichung DAIS, Taichung, ROC. Krtrll, D.F. and Borlaug, N.E. 1970. The utilization of collections in plant breeding. pp. 427439 In Frankel, O.H. and Bennett, E. (ed.). Genetic Resources in Plants — Their Exploration and Conservation. F.A. Davis Co., Philadelphia, USA. Singh, R.B. and Chomchalow, N. (ed.). 1982. Genetic resources and the plant breeder. International Board for Plant Genetic Resources Southeast Asia Program. Funny Press, Bangkok, Thailand. 140 pp. Stalker, H.T. and Chapman, C. (ed.). 1989. IBPGR training courses: Lecture series 2. Scientific management of germplasm: characterization, evaluation and enhancement. International Board for Plant Genetic Resources, Rome, Italy. 194 pp. Thomas, T.A. and Mathur, P.N. 1991. Germplasm evaluation and utilization. pp. 149—181 In Paroda, R.S. and Arora, R.K. (ed.). Plant genetic resources conservation and management, concepts and approaches. IBPGR, Regional Office for South and Southeast Asia, New Delhi, India. Watson, LA. 1970. The utilization of wild species in the breeding of cultivated crops resistant to plant pathogens. pp. 441—457 In Frankel, O.H. and Bennett, E. (ed.). Genetic Resources in Plants — Their Exploration and Conservation. F.A. Davis Co., Philadelphia, USA.

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9

Seed Processing and Preservation

L.M. Engle
Geneticist and Head Genetic Resources and Seed Unit, AVRDC Shanhua, Tainan, Taiwan, ROC

Introduction
For species with orthodox seeds, seed preservation is the most efficient means of maintaining large numbers of accessions. Fortunately, the great majority of seedreproduced economic species have orthodox seeds, i.e., they have seeds which can be safely stored over long periods without undue genetic change or loss of viability. The goal in seed preservation is to maximize the longevity of the stored seed at minimal cost. Longevity is affected by two factors: the status of the seeds before storage and the conditions surrounding the seeds during storage. Processing and handling of seeds for preservation A seed attains its highest quality (viability and vigor and therefore storability) at physiological maturity (Mamicpic 1989). It starts to deteriorate at physiological maturity. The aim of appropriate processing and handling is, therefore, to see to it that seed quality at entry to storage is comparable to quality at physiological maturity. However, at best, one can only delay or minimize seed deterioration from harvest to storage. Harvesting. One of the factors that affect longevity of stored seeds is the quality at harvest. Seeds should, therefore, be harvested at the stage of highest quality. This is at physiological maturity. This stage is before the usual harvest of a seed crop. Maximum dry weight is one criterion for physiological maturity. Some indices of physiological maturity is the black-layer formation in corn caryopsis and turning color of pods. For highest seed quality, priming is best although it is labor-intensive.

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Healthy, well-matured seeds carefully harvested in dry weather have the best storability. Harvesting should not be delayed to prevent the detrimental effects of unfavorable weather conditions and attack by pests and diseases on the seeds before harvest. Seed extraction and cleaning. For some crop species, the seeds are usually dried in the plant before harvesting (e.g., brassicas, legumes, and onion). The harvested pods of legumes and ears / panicles of grains should be threshed when the seed moisture content is between 12 and 16% (Ellis et al. 1985). Seeds at this moisture range are easier to thresh than wetter seeds and mechanical damage to seeds is minimized. Drying to this level could be done by air-drying with ventilation or in a cool dehumidified room. However, excessive drying should be avoided since very dry seeds are brittle and can be damaged during threshing. After threshing/shelling, seeds are cleaned of inert matters by blowing. Immature, shrivelled, sprouted, insect-, disease- and mechanically damaged seeds are separated. Only mature, clean, and healthy seeds are prepared for storage. Other species have fleshy fruits which are dried before seed extraction (e.g., gourds and okra). Fruits are picked as they ripen and dried before the seeds are removed. Others with wet fleshy fruits (e.g., eggplant, tomato, and cucumber) are harvested as they ripen. Seeds are extracted from the fleshy harvested fruits. The fruits may be subjected to some treatment to make extraction easier. For example, eggplants are beaten or rolled until soft. Whole peppers may be macerated. Extracted seeds are then directly dried or washed clean with water, if necessary. In every step, care should be exercised to minimize deterioration and mechanical damage to the seeds. Drying. The importance of drying seeds to low seed moisture content before storage is best illustrated by this example. When seed moisture content is decreased from 12 to 5%, seed storage life is increased 127 times (Zhang and Tao 1989). For long-term preservation, seeds are dried slowly to 3—7% moisture content (Tao 1985). Drying can be achieved by use of heat, dehumidifier, or desiccant. The use of heat (35—45°C) could result in seed deterioration, particularly for certain vegetable seeds (Tao 1988). IBPGR recommends that seeds are best dried in a drying room maintained at 15°C and 10—15% RH with good air circulation (Cromarty et al. 1985). This requires a sorption type air dehumidifier with refrigeration to lower the temperature and remove heat generated by the air dehumidifier. Small quantities of seeds are placed in open trays or porous bags. Small-seeded vegetables dry down to at least 6% in about 10 days (Cromarty et al. 1985). For larger seeds, a two-stage drying system is recommended. During the first stage, drying is done at 17°C, 40—45% RH. This would dry high oil-content or starchy seeds to about 7 and 12% equilibrium moisture content, respectively. The second-stage drying to 6% moisture content is done at 30°C, 10—15% RH.

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Another drying method is to use silica gel. Seeds, kept in porous bags, are placed together with silica gel in a closed container. Depending on species, seed moisture content can be lowered to 3–7% within a month (Zhang and Tao 1989). A 1:1 seed to silica gel ratio (by weight) is generally used. Faster drying with the use of higher proportions of silica gel is not recommended for some species like maize. For this purpose, seeds should also be harvested at the desiccation-tolerant stage. More recently, the drying of oily seeds (e.g., groundnut and onion) to between 2 and 4% is recommended (Ellis et al. 1990). Packaging. Packaging is done to keep each accession separate, to prevent contamination of the seeds from insects and diseases and to minimize absorption of water by the dried seeds. Three types of packaging are used for long-term preservation: glass, metal, and aluminum-plastic foil laminates. Any material impermeable to water vapor is theoretically suitable for packaging. Hermetically sealed containers have the advantage of preventing absorption by the seeds of water vapor from the atmosphere after drying. The desired amount of seeds are placed inside the packaging containers. For genetically homogeneous materials, 4,000 seeds are recommended to represent each accession. For heterogeneous materials, an accession should consist of 12,000 seeds (IBPGR 1985). Seed storage Seed preservation is achieved in several ways. It is safest and cheapest if life processes are reduced to the minimum level (i.e., seeds are put in a quiescent state). To prolong seed viability for long periods, the environmental conditions surrounding the seeds should be controlled. The most important factors influencing the viability of seed in storage are moisture content of the seed and storage temperature. The higher these two factors are, the more rapid is the deterioration of the seeds. Harrington (1963, as cited in Thomson 1979) has propounded two rules of thumb: For each 1% rise in seed moisture content and 5°C in storage temperature, the storage life of the seed is halved. Storing of high initial viability seed is definitely advantageous over low initial viability seed because viability can never be improved in storage. Seed moisture content. Seeds are hygroscopic and absorb moisture from the surrounding air. Over time, seed moisture content reaches equilibrium with ambient relative humidity and temperature. Low seed moisture content can be maintained two ways during storage. The seeds can be dried to the desired moisture content and hermetically sealed. Or they can be stored in containers that are not airtight and kept in humidity-controlled rooms.

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For long-term storage, seeds are dried to 5 (-1- or -1)% moisture content and packaged in airtight containers. For medium-term storage, seeds are dried to 7% moisture content or less and kept at 15—50% RH. Temperature. The storage life can be doubled for each 5°C reduction in seed storage temperature within the range of 0-45°C. Preferred long-term and medium-term conditions are -18°C or less and 0—10°C, respectively. The rule of thumb to indicate safe storage condition is "the sum of percent relative humidity and temperature in Fahrenheit (%RH +°F) should not exceed 100" (Thomson 1979).

Corollary activities
To ensure that seed and storage conditions are maintained at desired levels, regular monitoring is required. Seed viability needs to be tested over time. So do temperature and relative humidity in the storage rooms.

Procedures followed at GRSU
Tomato. Uniformly mature fruits are picked and placed in nylon mesh bags, one accession per bag, and properly labeled. The fruits are then crushed in the bags and placed in a large tank for fermentation. The time required for fermentation is 24 48 hours, depending on the prevailing weather and the maturity of the harvested fruits. Under-fermentation makes the seed difficult' to separate from the mucilaginous seed coatings. Over-fermentation is harmful to seed viability. Seeds are separated from the pulp by washing in water. Washed seeds are air-dried and then dried in an oven at 40°C or in a drying room at 15°C and 15% RH until the desired moisture content of 6—7% is reached. Dried seeds are packed in aluminum foil bags, with 12,000/ accession for longterm conservation and 50 seeds per pack for distribution. Mungbean. Dry pods are picked and placed in nylon mesh bags, air-dried, and threshed. Clean seeds are dried in an oven (40°C) or in a drying room (15°C, 15% RH). Soybean. Whole plants are cut and put in nylon mesh bags. After air drying, they are either threshed in bags or taken out and threshed manually. Clean seeds are dried again. Chinese cabbage. Seed maturity begins with the lower pods on each branch. Seed color changes from transparent at the very young stage to dark green, brown, and dark brown at maturity. When seeds in the top pods acquire a brown color, the entire branch is ready to be harvested. The harvested branches with attached pods are placed in nylon mesh bags for drying and threshing. Pepper. Ripe fruits are picked and placed in nylon mesh bags. They are air-dried for a short period. This also allows for ripening to proceed for some time. Seeds are then extracted manually or through a small grinder. When the grinder is used, the seeds are cleaned of debris by washing in water. Seeds are then placed in the drying room to dry to 7—8% moisture content.

documentation, and conservation References

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Cromarty, A.S., Ellis, R.H., and Roberts, E.H. 1985. Design of Seed Storage Facilities for Genetic Conservation. IBPGR, Rome. Ellis, RI-I., Hong, T.D., and Roberts, E.H. 1985. Handbook of Seed Technology for Genebanks. Volume I. Principles and Methodology. IBPGR, Rome. Ellis, R.H., Hong, T.D., Roberts, E.H., and Tao, K.L. 1990. Low moisture content limits to relations between seed longevity and moisture. Annals of Botany 65:493-504. Mamicpic, N.G. 1989. Factors Affecting Seed Longevity. Syllabus of Agronomy 172 (Seed Storage). Department of Agronomy, U.P. Los Banos. Tao, K.L. 1985. Standards for genebanks. FAO/IBPGR Plant Genetic Resources Newsletter 62:36-41. Tao, K.L. 1988. Assessment of physical facilities for genetic resources in East Asia. In Susuki, S. (ed.). 1987. Crop Genetic Resources. International Workshop on Crop Genetic Resources of East Asia. IBPGR, Rome. Thomson, J.R. 1979. Seed quality, seed multiplication systems, agronomy of seed production and seed storage. In IBPGR. 1979. Seed Technology for Genebanks, IBPGR, Rome. pp. 13-28. Zhang, X.Y. and Tao, K.L. 1989. Silica gel seed drying for germplasm conservation — practical guidelines. FAO/IBPGR Plant Genetic Resources Newsletter 75/76:1—5.

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10

Evaluation and Conservation of Germplasm Important Fruit Crops

A.K.M. Amzad Hussain Director Horticulture Research Centre, BARI Joydebpur, Gazipur, Bangladesh Genetic diversity has been the basis of all crop improvement — past, present, and future. Thus, it is our moral obligation to collect and protect our crop genetic resources before they are lost. Germplasm resources can be obtained through exploration, collection, or by exchange. Conservation refers to all the main activities involved such as collecting, documenting, preserving, and evaluating;, preservation means maintaining viable stocks of what has already been collected. BARI collected germplasm of lime, lemon, and other sour pulp citrus from different areas in Bangladesh during 1984-1986. Lemon, lime, and citrus In all, 25 lines of lemon, 11 lines of lime, and 7 lines of other sour pulp citrus species were collected. The collected lines were planted, three plants for each line, during 1990 at Joydebpur for evaluation. Some information generated from these lines are shown in Tables 1a—1c.

Table la. Lemon accessions collected, 1990 Accession no. SC-001 SC-001-1 SC-001-2 SC-002 SC-003 SC-004 SC-005 SC-006 SC-008 SC-009 SC-011 SC-012 SC-013 SC-014 SC-015 SC-016 SC-017 SC-018 SC-019 SC-020 SC-021 SC-022 SC-023 SC-024 SC-025 Local name Flowering time Fruit/plant no. wt. (kg) 60 7.50 50 6.50 45 10.17 25 6.53 8 1.20 112 8.96 68 12.31 12 0.67 55 11.00 7 1.75 26 7.14 7 1.30 7.96 7.04 6.21 Fruit wt. (kg) 125 131 226 261 150 80 181 56 200 250 286 185 215 201 478 147 196 Juice Disease incidence content Gummosio Canker Dieback (%) 40 Major Major All species 40 Major Major of citrus 34 Major Major carried minor 20 Major Minor infection 19 Major Major 29 Minor Minor 36 Minor Major 41 Minor 21 Major Major 31 Major Major Major Major 26 Major Major Major Major 20 Major Major 22 No Minor 19 No Major Major Major Major Major Major Major No Minor No Major No Major 27 Major Major Major Major Major Major Insect infestation Leaf miner is a major insect in all the lines

Seedless-1 Seedless-2 Seedless-3 Elachi Elachi Wild Minielachi Chinalebu Round Lemon Pati-1 Jara(rough) Shashni-1 Column 60 Gabtali Lebu Trishal Lebu Jara Long 1 Jara Long 2 Jara Long 3 Jara Long 4 Pati - 2 Shashni-2 Shashni-3 Shashni-4 Unknown 1 Unknown 2 Unknown 3

January—February January—February January—February February—March 15 February—15 March January—February January—February Mid-February—March Mid-January—mid-March March—mid-April Mid-January—mid-March February—March No flowering January—mid-March 37 January—mid-March 35 January—February 13 March—mid-April 5 (2 yrs) January—February 10 (2 yrs) March—April 5 (2 yrs) -

February—March February—March January—March

28 5 20 (2 yrs)

4.17 0.98 -

co

Table lb. Lime accessions collected, 1990 Accession Local name no. SC-055 SC-056 SC-057 SC-052 SC-054 SC-051 SC-053 SC-059 SC-058 SC-060 SC-061 Kagzi Patia Kagzi
Comilla

Flowering time

no. January February January February
January

Fruit/plant wt. (kg) 65 2.34 65 2.34 2.55 3.90 2.75 3.07 -

Fruit wt. (kg) 36 36 37 39 32 36 -

Juice content (%) 34 34 23 28 36 35 -

Disease incidence Gummosio Canker Dieback Minor Minor Minor No Minor Minor Minor Minor Minor Minor Major Major Major Major Major Major Major Major Major Major Major Major Major Major Major Major Major Major Major Major

Insect infestation Leaf miner is a major insect in all the lines

Kagzi
Oblong

69 100 86 64 -

Kagzi
Ishurdi

Kagzi
Oval

Kagzi
Ishurdi

Kagzi
Faridpur

Kagzi
Unknown

February January February 15 January 15 February 15 January 15 February January February . January -

Kagzi Thailand Kagzi Jhumka (Kagzi-big)

-

-

Table ic. Other sour pulp citrus species collected,1990 Accession Local name no. SC-092 SC-085 SC-086 SC-093 SC-081 SC-084 SC-083 Adazamir Ashkar Katuzamir
(Srimagal)

Flowering time

February 28 March Mid-February No flowering No flowering Mid- January 1st week of March No flowering No flowering

Fruit/plant no. wt. (kg ) 6 0.83 3 1.92 -

Fruit wt. (kg) 138 640 -

Juice content (%) -

Disease incidence Gummosio Canker Dieback No No Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor Minor

Insect infestation Leaf miner is a major insect in all the lines

Moisheada Ghora Lebu Karul Zamir Katazamir Sylhet

-

-

-

84 Pomelo

Germplasm collection, evaluation,

Some pornelo germplasm accessions have been collected through fruit shows held for the Rajshahi region and some through personal contacts. They were collected and planted during 1984-1986 at Joydebpur. Three plants were planted for each line. These are now being evaluated. Some pomelo lines which have been evaluated to some extent are shown in Table 2. Of these Myn-3, BL-2, B-20, and Da-6 were found to be very good in terms of both production and quality of fruits. Custard apple During 1989, 27 lines of custard apple were collected. Seedlings of these lines were planted in 1991. Some of the lines have already fruited. These are shown in Table 3. Mango A total of 76 varieties were collected (Table 4). Of these, 58 local and 18 exotic varieties were collected and planted. The plants were from four to eight years old.
Litchi

For litchi (lychee), 10 varieties were collected and evaluated (Table 5). Guava Nine varieties of guava were collected and evaluated (Table 6).
Other fruits

Germplasm of other fruits such as ber, banana, plantain, papaya, wax apple, and sapota were also collected and evaluated. For ber, the following varieties were collected: Rajshahi Kul, Boll borai, Bilati Kul, Narikeli Kul, Joydebpur Kul, Hasan Kul, Zeman Kul, Hadi Kul (Table 7). For banana, 10 varieties were collected: Sabri, Amritsagar, Champa, Kabri, Mehersagar, Lacaton, Vablery, Basrai, Grand nain, and Agnishar (Table 8). Yield/plant of these varieties is under evaluation. The varieties of plantain, papaya, wax apple, and sapota that were collected and evaluated are shown in Tables 9, 10, 11, and 12, respectively.

Table 2. Pomelo lines evaluated Accession Flowering time no. B-25 February B-20 Mid-February P-32 January—February F-1 Mid-February—March Da-3 January D-2 January—1st week of March BI-2 20 December, 7 February Raj-75 January—February Myn-3 20 January—February Da-5 December—February P-2 January—February B1-3 Mid-January—February Raj-51 Mid-January—mid-March Raj-2 January—February P-52 Mid-January—mid-March P-38 January—mid-March R-52 Mid-January—mid-March D-29 January—February R-32 January—February R-34 January—February Raj-41 January—February Raj-49 Mid-February Da-6 Mid-January—mid-March Fruit shape Orange shaped Obovoid Orange shaped Orange shaped Orange Shaped Obovoid Obovoid Obovoid Orange shaped Subglobose Subglobose Globose Pyriform Subglobose Obovoid Obovoid Obovoid Subglobose Globose Obovoid Ovoid Obovoid Globose Fruit/plant no. wt. (kg) 3 1.60 1 0.80 16 15.49 1 0.74 1 0.74 2 1.38 9 5.66 2 11.20 6 4.88 5 3.80 36 18.40 11 10.14 11 10.65 9 6.80 4 2.70 8 6.17 10 9.59 6 5.10 10 9.98 9 6.25 1 0.69 1 1.00 6 3.40 Flesh color Reddish Reddish Reddish Deep red Whitish Reddish Yellowish Reddish yellow Deep red Reddish yellow Reddish yellow Deep red Deep red Reddish yellow Reddish Reddish Reddish Reddish Reddish Reddish Reddish Reddish Deep red Softness Very Medium Medium Less Less Medium Medium Medium Very Medium Medium Medium Very Very Less Medium Less Medium Medium Less Less Less Very Sweetness Less Medium Sour Medium Medium Sour Very Sour Very Sour Sour Very Less Less Medium Sour Sour Less Medium Medium Less Less Very Bitterness No No Less Very Very No No No No Less Less Less No Less Less No No Less Very Less No Less No Disease incidence Tolerant to all major diseases except gummosis which is found in the older plants Insect infestation Leaf miner is a major insect in all the lines

Table 3. Custard apple lines collected by BARI
Accession Time of new no. flush CA-001 February CA-002 February CA-003 February—mid-March CA-004 February—mid-March CA-005 February—mid-March CA-006 February CA-007 February—mid-March CA-008 February—mid-March CA-009 February—mid-March CA-010 February—mid-March CA-011 February—mid-March CA-012 February—March CA-013 February—March CA-014 Mid-February—7 March CA-015 Mid-February—7 March CA-016 Mid-February—7 March CA-017 February CA-018 February—mid-March CA-019 February CA-020 February CA-021 February—7 March CA-022 March CA-023 March CA-024 Mid-February—mid-March CA-025 Mid-February—mid-March CA-026 Mid-February—mid-March CA-027 Mid-February—March Flowering time Mid-February—March Mid-February—mid-March Mid-February—mid-March February—March Mid-February—March March February—7 March
Mid-February—March

Fruit wt. (g) 413 278

Edible portion wt. (g) (%) 238 58 209 75

Seeds/fruit no. wt. (g) 62 21 25 8

Sweetness Very Very

Disease incidence No major disease observed

Insect infestation Scale insect is a minor insect

282 182

179 80

63 44

39

13

Less

Mid-February—March Mid-February—March Mid-February—March Mid-February—7 April Mid-February—7 April March—15 April March—15 April March—15 April March Mid-March—mid-April Mid-February—mid-March Mid-February-mid-March Mid-February—mid-March Mid-March—mid-April
Mid-March—mid-April Mid-March—mid-April Mid-March—mid-April

43

14

Very

280

178

61

6-

18

Very

225 210 213 232 176 217 178

1130 115 131 156 90 96 98

57 54 61 67 51 44 56

25 38 27 47 25 36 41

10 12 11 15 7 10 12

Very Very Very Very Less Medium Less

C

"'
n

0

March—15 April March—15 April

documentation, and conservation

87

Table 4. Mango germplasm accessions collected * Variety name 1. Anwar Ataul 2. Ananas 3. Aswina 4. Ahai-ping 5. Bombai-1 6. Bombai-2 7. Bira 8. Begumphuli 9. Bhuto Bombai 10. Brindabani 11. Baramashi-1 12. Bhabani 13. Bimala 14. Begum Pasand 15. Chini Pata 16. Carabao 17. Dilsad 18. Dilwala 19. Dowri 20. Dusheri 21. Fonia 22. Fazli 23. Fazli Kalan 24. Copal Bhog 25. Him Sagar 26. Hayati 27. Kohitoor 28. Koninoor 29. Kuapahari 30. Kanchan Khosal 31. Khirsapat 32. Kalua 33. Kishanbhog 34. Khudi Khirsapat 35. Khangra Bacha 36. Kancha Mitha 37, Kala Chini 38. Inwin 39. Larua 40. Langra 41. Love e-Moshgul 42. Lata Bombay 43. Lakhno 44. Lata (dwarf) 45. Malada-1 46. Nawab Pasand 47. Ram Pasand 48. Raj Rani 49. Suraja Puri 50. Summer Best (Continued) Number 3 3 3 3 3 3 2 3 3 3 3 3 3 3 3 3 3 3 3 2 3 3 3 3 3 3 3 2 3 3 2 2 1 2 2 3 3 2 3 3 3 3 2 3 2 1 1 1 1 3 Age 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 3 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months Source ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka ARI, Dhaka

88 Table 4. continued... Variety name 51. Suba Pasand 52. Sinduri 53. Sabia 54. Totapuri 55. Zardalu 56. Amrapalli 57. Chausa 58. Mallika 59. Little Flower 60. Maldah-2 61. Kent 62. Bhabani Chaura 63. Pelmer 64. Kensington 65. Zill 66. Keitt 67. Pahatan 68. Nizaria 69. Code no. 12 70. Code no. 6 71. Rudy 72. Code no. 7 73. Code no. 14 74. Hayden 75. Code no. 5 76. Kazla-04
(Baromashi)

Germplasm collection, evaluation,

Number 1 1 2 1 3 3 3 2 3 3 3 3 3 3 1 3 3 2 3 3 1 1 1 1 1 3

Age 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 8 years 10 months 4 years 10 months 4 years 10 months 4 years 10 months 4 years 10 months 4 years 10 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months 4 months

Source ARI, Dhaka ARI, Dhaka ARI, Dhaka ART, Dhaka ARI, Dhaka India India India Dhaka City Sreepur, Gazipur Senegal Dhaka City Benegal Australia Senegal Senegal Philippines Nizeria Cuba Cuba Senegal Cuba Cuba Australia Cuba ARS, Kazla, Rajshahi

From a project/experiment titled "Evaluation of mango germplasm".

Table 5. Litchi (lychee) germplasm varieties collected by BARI Variety 1. China -1(L009) 2. China - 3 (L003) 3. Bombai (L004) 4. Madrajee (L005) 5. Mongalbaria (L007) 6. Mazaffarpuri (L006) 7. Bedana (L002) 8. China origin (L008) 9. Maotail (LO01) 10. Kadmi (L010) Plant age: 8 years Yield/plant (kg) 72.0 9.6 9.2 5.8 7.8 10.9

documentation, and conservation Table 6. Guava varieties collected by BARI
1. 2. 3. 4. 5. 6. 7. 8. 9. Variety Kazi Piara Mukundapur Swarupkathi Kanchannagar King Allahabad Strawberry Guava Sikim Piara Seedless Piara Yield/plant (kg) 96.3 44.9 62.3 32.4 5.7 Age 6 years 6 years 6 years 6 years (3 years)

89

Table 7. Ber varieties collected by BARI
1. 2. 3. 4. 5. 6. 7. 8. Variety Rajshahi Kul Boll Borai Bilati Kul Norikeli Kul Joydebpur Kul Hasan Kul Zaman Kul Hadi Kul Yield/plant (kg)

Table 8. Banana varieties collected by BARI
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Variety Sabril Arnritsagar Champa Kabri Mehersagar Lacaton Vablery Basrai Grand Nain Agnishar Yield/plant (kg) -

-

Table 9. Plantain varieties collected by BARI
1. 2. 3. 4. 5. 6. Variety Anazi Arnritsagar Champa Kabri Kanthali Hazari Yield/plant (kg) 8.7 7.0 7.3 6.3 7.0 7.3

90 Table 10. Papaya varieties collected by BARI 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Variety Shahi P017 P014 P015 P013 P016 P022 P018 P019 P020 P021

Germplasm collection, evaluation,

Yield/plant (kg) 34.6 31.9 29.9 22.8 41.5 28.5 35.3 31.1 20.8 35.5 46.3

Table 11. Wax apple varieties collected by BARI 1. 2. 3. Variety White Red Green Yield/plant (kg)

Table 12. Sapota varieties collected by BARI 1. 2. 3. Variety Round - flat Small - round Oval Yield/plant (kg) 106.0
21.7

22.7

documentation, and conservation

91

Appendices

AVRDC-GRSU Collection Record Sheet Collecting institute Collectors Collection no. Date of collection Country District/Province Location of collection site name of village: nearest town: distance (in kin): direction: Grower name Latitude of site Longitude of site , Altitude of site Site temperature Site rainfall Crop collected Genus Variety/ Local name Meaning Variety name language Usage (specify)

COLLECTION SOURCE: 1. farmland 2. backyard/home garden 3. farm store / threshing place 4. village market 5. commercial seed shop (name 6. agricultural institute 7. bordering field 8. natural vegetation/wild 9. others (specify)

GENETIC STATUS: 1. wild 2. weedy 3. primitive cultivar/landrace 4. improved OP cultivar 5. hybrid cultivar 6. others (specify) SAMPLE TYPE: 1. single plant 2. pure line/clone 3. mixture/population (clone/pure line) 4. open-pollinated 5. others (specify)

92 SAMPLING METHOD 1. random 2. nonrandom (specify) MATERIAL: 1 seed 2 seed 4 others (specify) 3 pod

Gerinplasxn collection, evaluation, SOIL TEXTURE: 1. sand 2. sandy loam 3. loam 4. clay loam 5. silt 6. clay 7. highly organic (peat/muck) 8. others (specify) DRAINAGE: 1. poor 2. good 3. moderate 4. excessive SOIL COLOR: 1. black 2. dark brown 3. light brown 4. gray 5. yellow 6. red 7. others (specify) STONINESS: 1. none 2. medium 3. low 4. rocky DISEASES AND PESTS:

CULTURAL PRACTICE: shifting: Yes; No terraced: Yes; No direct seeding: Yes; No transplanting: Yes; No intercropping: Yes; No intensive: Yes; No rotation crop: Yes; No irrigated: none; by hand furrow; overhead; drip HERBARIUM SPECIMEN: Yes; No PHOTOGRAPH: Yes; No SOWING MONTH: TRANSPLANT MONTH: HARVEST MONTH: TOPOGRAPHY: 1. swamp 2. flood plain 3. level plain 4. undulating 5. hilly 6. mountainous 7. others (specify) SITE: 1. level 2. slope 3. plateau 4. depression

NOTES: (Associated wild, weedy and crop species, special plant characters and morphological variation, status of genetic erosion, other observations.)

documentation, and conservation Test Questions 1. Define the following terms: a. genetic diversity b. genetic erosion c. genetic resource d. active collection e. conservation f. characterization g. preliminary evaluation Enumerate and describe briefly the categories of the genetic resources of a crop species. Enumerate methods of conserving germplasm. Why is there a need to assemble a germplasm collection? What are the recommended seed moisture contents, temperature and relative humidity for short-term, medium-term, and long-term storage? Give an example of a descriptor and descriptor state. True or false 7.

93

2. 3. 4. 5.

6.

In the tropics, sun drying is best for seeds that are to be stored for long-term conservation. Solar energy is free and abundant. One may keep newly collected materials in plastic bags since these are readily available. Collecting forms are not necessary. They are too complicated and takes some time to be accomplished. The planting materials are more important.

8. 9.

10. Orthodox seeds are best stored at low moisture content, low temperature and low relative humidity.

94 Multiple choice (circle one best answer each): 11. The primary users of plant genetic resources are: a. extension agents b. administrators c. plant breeders d. curators

Germplasm collection, evaluation,

12. Plant germplasm evaluation is the primary responsibility of: a. extension agents b. students c. multidisciplinary scientific teams d. soil scientists 13. Germplasm evaluation data describe traits related to: a. survival b. adaptation c. productivity d. quality e. all of the above 14. A score between 1 and 5 for disease resistance is an example of which scale of measurement: a. ratio b. ordinal c. nominal d. direct 15. Evaluation of disease resistance should be conducted with: a. known races of the pathogen b. avirulent strain of the pathogen c. no control plants d. one variety only 16. Germplasm should be evaluated only: a. in areas where it is adapted b. under disease epidemics c. for highly heritable traits d. by standardized procedures 17. Pre-breeding" is practiced: a. on finished varieties b. to enhance germplasm for use by breeders c. only with interspecific hybrids d. by extension agents
"

documentation, and conservation 18. Germplasm pools are: a. purelines b. intermated genetic resources c. based only on cross-compatibility d. for aquatic species only 19. If a cross between germplasm pool A and new accession #3 shows hybrid vigor: a. add accession #3 to germplasm pool A b. separate accession #3 from germplasm pool A c. backcross accession #3 with germplasm pool A d. discard accession #3 20. Genotype x environmental interactions are important when evaluating: a. highly heritable traits b. molecular markers c. yield d. mature fruit color 21. What is a good seed? 22. Write the percentage moisture at which most of the vegetable crop seeds are dried. 23. List the storage methods used for vegetable crops — name only. 24. Name two factors which play a major role in increasing/ decreasing storage life of vegetable seeds. 25. Write the best temperature for short, medium, and long storage of vegetable crops. 26. What is genetic erosion? What are the causes of erosion? 27. What is a photosensitivity variety? How can the plants be made dwarf? 28. List some salient characters of kakrol germplasm.

95

True or false 29. A documentation system should include as many data as can be recorded. T/F 30. A national genetic resource center must maintain all plant species found in a country. T/F 31. Different gene banks must have a documentation system that help attain their mission in the most efficient and practical manner. T/F

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