Docstoc

Benefits of cooperative tree breeding for Australia's sheep- wheat

Document Sample
Benefits of cooperative tree breeding for Australia's sheep- wheat Powered By Docstoc
					Benefits of cooperative tree breeding for Australia’s sheep-
wheat belt

Author: David Bush (Ensis), Tom Baker (University of Melbourne), Trevor Butcher
(Forest Products Commission), Chris Harwood (Ensis), Michael Henson (Forests NSW),
Rosemary Lott (Rural Industries Research and Development Corporation) and Sue
Shaw (ForestrySA).


Abstract
The Australian Low Rainfall Tree Improvement Group (ALRTIG) was established in 1999
and has a mission to: produce genetically improved planting material for farm forestry in
the low rainfall areas of southern Australia, and inform tree growers of its availability.
The group is a cooperative of State and Commonwealth Government stakeholders in
low rainfall farm forestry research, and is supported by the Joint Venture Agroforestry
Program. The participation of farmers in establishing the trials has also been of
paramount importance. The value of the cooperative approach is discussed.

ALRTIG’s area of focus has been the southern sheep-wheat belt, including parts of
NSW, Victoria, South Australia, and Western Australia. To address the salinity problem,
large areas need to be revegetated with deep-rooted woody perennials. While the best
environmental outcome might arise from revegetation derived from appropriately
sampled germplasm of naturally occurring local species, it is argued that properly sited
deployment of other species that provide economic benefits to growers as well as
environmental benefits is warranted.

ALRTIG has established over 100 ha of seed orchards and other trials that will provide
information for the genetic improvement of a small number of eucalypt species and
exotic softwoods. Data pooled from the partners’ pre-existing research and results from
newly established trials are showing the significant benefits afforded by tree breeding.
Genetic improvement is likely to be one of the keys to achieving economically viable
revegetation at the scale required to give significant environmental benefits.

ALRTIG have promoted the use of genetically improved planting stock though their
website, field days, conferences and the extension networks of the partner
organisations.
Why breed trees for the sheep-wheat belt?
Commercial reasons for planting trees and shrubs in the sheep-wheat belt include farm
amenity and shelter for stock, diversification of income to include that derived from wood
or other plant products, carbon sequestration and possibly protecting land prone to
dryland salinity and erosion and/or returning land already affected by these to
productivity. In recent decades there has been a growing awareness of wide-scale
environmental problems such as dryland salinity, and amelioration by planting of deep-
rooted perennial vegetation has been identified as a partial solution (Stirzaker et al.
2002). Dryland salinity is a particularly serious problem, and there has been plenty of
speculation about the advent of salinity credits. Like carbon credits paid for greenhouse
gas emission offsets (another possible commercial driver for planting), salinity credits
might be paid to farmers who plant deep rooted vegetation in places where reduced
recharge will lead to lower catchment salinity. These commercial benefits are in addition
to the substantial direct environmental benefits of planting, such as enhanced biological
diversity, and for some plantings, conservation of native ecosystems.

There are plenty of deep rooted species endemic to Australia’s sheep-wheat belt
available for wide-scale planting, so what do we stand to gain from genetic
improvement? If the aim of the re-vegetation is solely to draw down water for
amelioration of salinity and/or to enhance biodiversity, the answer is probably ‘not much’.
However, if the vegetation must ‘pay its way’ – and it has been argued that it must if the
scale of revegetation needed to impact on the salinity problem is to be achieved – then
genetic improvement has much to offer. Genetic improvement has the potential to
increase the value of tree and shrub crops to the point where they are sufficiently
commercially attractive to plant at a significant scale. Without genetic improvement,
there are very few tree and shrub species that are both hardy and yield enough
commercial products to provide the incentive that is needed to plant at a substantial
scale. What is needed are woody plants that:

   1. are drought resistant and can reliably withstand the low rainfall environment;
   2. can deal with other ‘environmental challenges’ such as salinity, sodicity,
      alkalinity, waterlogging and frost; and,
   3. produce merchantable products such as essential oils or other chemicals, fibre,
      fodder, timber, charcoal and fuel/energy at an acceptable rate per hectare per
      year.


Cooperative Tree Breeding
A workshop organised during 1998 by the Joint Venture Agroforestry Program and the
South Australian State forestry research organisations, involving tree improvement
stakeholders from the southern States, examined the status of low rainfall tree
improvement research. Participants recognised that while the discrete, small research
programs being undertaken by southern Australia’s various researchers had made
significant achievements, a cooperative model of low rainfall tree improvement may be
more effective. The concept of an Australian Low Rainfall Tree Improvement Group
(ALRTIG) was put forward. ALRTIG commenced in 1999, supported by the Joint Venture
Agroforestry Program and its five State and Commonwealth partners with a mission to:
produce genetically improved planting material for farm forestry in the low rainfall areas



                                                           Veg Future 06: the conference in the field
of southern Australia, and inform tree growers of its availability. ALRTIG chose twelve
‘key species’ on which to focus genetic improvement activities including:


Spotted gums (Corymbia maculata and variegata)
Red ironbarks (Eucalyptus tricarpa and sideroxylon)
River red gum (E. camaldulensis)
Swamp yate (E. occidentalis)
Sugar gum (E. cladocalyx)
Oil mallee (E. horistes)
Blue mallee (E. polybractea)
Maritime pine (P. pinaster)
Brutian pine (P. brutia)
Radiata pine (P. radiata)



What do we breed for?
There are numerous naturally occurring species in the sheep-wheat belt that are already
drought resistant, and that are well adapted to at least some of the other rigours of the
environment. Anyone who has travelled in the sheep-wheat belt will recall having seen
sparsely scattered, hardy trees and shrubs that have obviously withstood numerous
droughts. However these trees and shrubs have typically not had to compete for light in
a closed forest, and they therefore have not evolved to be tall and straight: rather they
tend to be of short to medium height with heavy branching and spreading crowns. One
approach to breeding, therefore, is to target species that are already well-adapted
environmentally, and improve traits such as stem form, branching and growth rate.

An alternative approach would be to take species that are already tall and straight
(typically from wetter places) and try and improve their drought resistance.

ALRTIG has opted for the former approach. It is much quicker, easier and more
successful to improve the growth and form traits than it is to try and work on
environmental adaptation. The straightest tree from a stand already growing in the low
rainfall zone can be selected instantly, and included in a breeding program, whereas it
would take at least half a rotation to determine whether or not any trees grown from seed
collected from straight trees in the higher rainfall zone might be more drought hardy than
others.

The traits ALRTIG have selected in the twelve key species are:

   •   Vigour
   •   Stem straightness (in species for wood production)
   •   Branching (in species for solid wood production)
   •   Oil yield (in oil mallees)
   •   Apparent pest and disease resistance (all species)



                                                            Veg Future 06: the conference in the field
In later generations of breeding, wood quality traits will become more important. For
example, the ALRTIG key hardwood species may lend themselves to sawn wood and
natural durability applications, so resistance to decay, strength, stability and wood colour
may be important traits.



What progress has been made?
ALRTIG has made significant progress. Firstly, at the project’s commencement in 1999,
pooling of data from pre-existing trials belonging to the partners yielded information
about which provenances of some species should be used for commercial planting. For
example, Figure 1 shows a combined analysis of sugar gum trial data from South
Australia and Victoria. This analysis (plus other corroborating data not presented here)
shows that the most vigorous natural provenances, on a range of sites, are those from
Kangaroo Island (e.g. Flinders Chase). Those from the southern Flinders Ranges (e.g.
Wirrabara and Wilmington) are a bit less vigorous, while those from the Eyre Peninsula
(e.g. Wanilla) lack vigour. However, better than any of the natural provenances are
landrace1 materials from western Victoria (e.g. Lismore). The landrace material also has
the best form, followed by southern Flinders Ranges, Kangaroo Island and then Eyre
Peninsula provenances. This and other information of this sort has been very valuable
for growers and is available on the ALRTIG website (www.ffp.csiro.au/alrtig).

Secondly, ALRTIG has established over 70 trials and seed orchards throughout
southern Australia (Table 1). Each of the trials was carefully planned to play a part in
ALRTIG’s genetic improvement strategies, (e.g. Boardman et al. 2002, Harwood et al.
2005) which can be downloaded from RIRDC’s free publications area (access from
www.rirdc.gov.au). Broadly, the trials fall into three categories:
   1) progeny trials, which are designed to test the performance of different genetic
       materials within species and that form the basis of breeding populations;
   2) Seed orchards, that are designed to produce seed (often we have dual purpose
       trials that do 1 and 2);
   3) Gain trials that are designed to test how much better improved seed sources are
       than each other and relative to unimproved ones.




1
 Landraces are planted stands, outside of the species natural range, that are adapted to the local
conditions through anthropogenic or natural selection.


                                                                   Veg Future 06: the conference in the field
Table 1. ALRTIG trials established between 2000 and 2005 by location and type

Species                                  No. trials/State location                                               Types of trial
C. maculata                              2 NSW, 6 VIC, 2 WA                                                      GT, PT-SSO
E. cladocalyx                            3 NSW, 4 SA, 5 VIC, 4 WA                                                GT, PT, PT-SSO
E. camaldulensis                         2 WA                                                                    PT, GT
E. sideroxylon                           2 NSW, 1 VIC                                                            PT-SSO
E. occidentalis                          3 SA, 5 VIC, 4 WA, 2 NSW                                                GT, PT, PT-SSO
E. tricarpa                              2 VIC, 1 NSW, 1WA                                                       PT, PT-SSO
E. horistes/E.                           1 NSW, 1 SA, 1 VIC, 1 WA                                                GT
polybractea
P. pinaster                              2 TAS, 2 VIC, 2 NSW, 2 WA, 2 SA                                         GT
P. brutia                                1 NSW, 1 ACT, 2 WA, 2 SA                                                MP, NP-CSO
P. radiata                               1 NSW, 1 SA, 1 WA                                                       PrT
GT = gain trial, PT = progeny trial, SSO = seedling seed orchard, CSO = clonal seed orchard, MP = main
breeding population, NP = nucleus breeding population, PrT = provenance trial




Figure 1. Combined trial data from ALRTIG partners’ sugar gum trials (after Bush et al.
in press).




                                  800


                                  700


                                  600

                                   500
                    Height (cm)




                                   400                                                                                         Gumeracha
                                                                                                                             Kersbrook
                                    300
                                                                                                                           Gumeracha BG

                                    200                                                                                  Montarra
                                                                                                                      Browns Hill
                                                                                                                                           al




                                        100
                                                                                                                                        tri




                                                                                                                 Kalangadoo
                                                                                                                                     of
                                                                                                                                      n




                                          0
                                                                                                                                   tio




                                                                                                              Shelford
                                                                                                                                 ca
                                              Lismore




                                                                                                                               Lo
                                                        Flinders Chase




                                                                                                            Werneth
                                                                         Wirrabara



                                                                                     Wilmington




                                                                                                  Wanilla




                                                                         Provenance




Trials established by ALRTIG in 2000 and 2001 are now yielding valuable data. Figure
2a and 2b show data from 3-year measures of ForestrySA’s Bordertown sugar gum trial.
The results from these trials again show that while provenances from the southern
Flinders Ranges have good form, and those from Kangaroo Island have good vigour, the
best all-round performers are those from planted and improved stands including the
landraces in western Victoria and South Australia. Molecular genetic studies (McDonald
et al. 2003) and South Australian State records have shown that the landrace materials



                                                                                                                      Veg Future 06: the conference in the field
were derived from the southern Flinders Ranges, probably in ca. 1875. The Kersbrook
Seed Production Area (SPA) is probably the best-bet seed source, as it has been
selectively thinned so that only the best trees from the best provenances remain. While
seed from good trees in planted stands in western Victoria, such as Wail, Lismore and
Majorca certainly can perform well, the grower needs to have surety that the seed has
been collected from suitable trees that are both of good form and that have flowered
quite heavily, and synchronously with others nearby, to ensure a good chance of
outcrossing.

This and other examples of early data from ALRTIG trials will be published shortly by
RIRDC (Bush et al. in press). Additionally, a 5-year measure of 20 ALRTIG trials is
planned for 2006/2007. Metadata from these trials will be compiled and published, and
made available to other researchers.

Figure 2a. ForestrySA Bordertown sugar gum trial height by provenance and grouped
by region of provenance



                   50
                   45               Av. s.e.d. = 3.108
                   40
   Height (dm)




                   35
                   30
                   25
                   20
                   15
                   10
                    5
                    0
                                  S. e




                                       ca
                                 C r




                                M rr
                                        A.




                              ilm le




                                        F.
                      Fl ne .P.
                         C se r




                       W ilm n
                                 M il




                                ar n
                                       se
                             rs ve
                                        e




                                        a
                                        r




                            W ngto

                            ab to
                                      u




                            W ab
                            oo mo




                                     S.
                           Ch iv




                                     P.

                                     W



                                     or
                                    ha




                                    tB
                           yg N
                          de t Ri




                         irr ing
                        rs n R




                        S. ark
                                  aj




                                  a
                       rs Lis




                                  i
                               k




                            em
                               a
                     de rica




                         tR
                         br
                 Fl me




                        in




                       M
                      A




                    Ke




                                  Planted/im proved
                   in




                   Kangaroo Is.
                                       stands            S. Flinders
                      group
                                                            group




                                                            Veg Future 06: the conference in the field
Figure 2b. ForestrySA Bordertown sugar gum trial form (forking) by provenance and
grouped by region of provenance.


          6
                   (6 = no forks, 1 = fork at base)




          5
                 Av. s.e.d. =0.5595
          4
                              Forking score




          3
          2
          1
          0



                          ca



                            e
                            r



                    S. r
                  M A.




                   ar .
                           e
      Fl can P.
               rs ver




                ilm n
                  Li ail




       M ara n
               ne se




             em S.F
                        ive




                           r




                         or




                         bl
             W gto

             ab to
             oo Bu
                       P.
                         .




                       W
                       or
                       a
           er e N




                     ka
          irr ing
                    sm
                       i


                    tR
                     R

         C Ch




                    aj




                    in
                     t
                  M




                ilm
      Am has




                 k




             W
            yg
           de
             i
            C




         tR
         br




        S.
        in
        rs




       W
       rs




               Kangaroo Is.
     de




    Ke




                                      Planted/im proved     S. Flinders
   in
 Fl




               group                       stands           group




Where to from here?
ALRTIG has established a valuable legacy of coordinated trials and seed orchards
throughout the southern Australian States. These plantings, and the genetic
improvement strategies that they embody, have the capacity to supply genetically
improved seed of a range of key species and to ensure that continuous genetic
improvement is possible. Surveys of major nurseries supplying the low rainfall forestry
sector have shown that demand for planting stock has risen slightly since 1999,
especially in the case of sugar gum and spotted gum. Mallees such as oil mallee and
blue mallee are being planted relatively extensively in Western Australia, and more
recently in NSW for carbon sequestration, and short rotation options are receiving
increased attention. The next three years will see substantial quantities of genetically
improved seed produced from ALRTIG’s SSOs. The challenge will be to ensure that
growers are aware that this seed is available and realise the substantial benefits that it
will afford over wild germplasm.




                                                            Veg Future 06: the conference in the field
Acknowledgements
Thanks to John Doran (Ensis) and Kimberlie Rawlings (Greening Australia) for helpful
suggestions and review of this paper


References

Boardman, R., Bush, D., Butcher, T., Harwood, C., Spencer, D. and Stackpole, D.,
(2002). Australian Low Rainfall Tree Improvement Group compendium of softwood
breeding strategies. Rural Industries Research and Development Corporation, Canberra.
RIRDC Publication No. 02/028. 56 pp.

Bush, D., Butcher, T., Harwood, C., Bird, R. Henson, M. and Shaw, S. (in press).
Australian Low Rainfall Tree Improvement Group Progress: 1999-2005. Rural Industries
Research and Development Corporation, Canberra. 43 pp.
Harwood, C.E., Bird, R., Butcher, T., Bush, D.J., Jackson, T., Johnson, I., Stackpole, D.
and Underdown, M. (2005). Update of Australian Low Rainfall Tree Improvement Group
Breeding Strategies. Rural Industries Research and Development Corporation,
Canberra. RIRDC Publication No. 05/023. 17 pp.
McDonald, M.W., Rawlings, M., Butcher, P.A. and Bell, J.C. (2003). Regional divergence
in E. cladocalyx (Myrtaceae). Australian Journal of Botany 51: 393-403.

Stirzaker, R., Vertessy, R. and Sarre, A. eds. (2002). Trees, water and salt: an
Australian guide to using trees for healthy catchments and productive farms. RIRDC
Publication No. 01/086. Rural Industries Research and Development Corporation,
Canberra.




                                                          Veg Future 06: the conference in the field

				
DOCUMENT INFO
Shared By:
Categories:
Stats:
views:13
posted:4/25/2010
language:English
pages:8
Description: Benefits of cooperative tree breeding for Australia's sheep- wheat ...