Ground Cover North : Ground Cover 058 October-November 2005 - North
15 Plant breeding n Amid tossed coins, breeding jokes and a Port Adelaide 'love child', Australian Grain Technologies wheat breeder Dr Andy Barr brought the concept of modern plant breeding to Eyre Peninsula graingrowers. Dr Barr -- who was recently recognised, as part of the South Australian Cereal Breeding Team, with the inaugural Premier's Science Award -- used coins and two volunteers to show how the random outcome of flipping a coin illustrates the way in which parents' genes make it into their progeny. A 'Port Adelaide football fan' was then produced after tossing coins for the desirable traits. Similarly, plant breeders have used selective breeding to produce progeny with the right characteristics -- choosing parents with the required genes and cross-breeding them. However, in the past 10 years a vast array of new and more accurate technologies have been added to plant breeders' toolkits -- modern plant pathology theory, improvements in computers, statistics and information technology, biotechnology such as molecular markers, plant tissue culture, mechanised instruments and, more recently, robotics. These have reduced the time taken to breed new cereal varieties from 14 years to almost half that, and increased the scale and scope of plant breeding to tackle previously insurmountable challenges. In this same period, plant biotechnology has also developed to the stage where genetically modified varieties can potentially be produced even faster than with most modern conventional approaches, and with more accuracy in terms of which genes are introduced. "Plants have a very large number of genes," Dr Barr explained. "Barley has 30,000 genes and wheat 100,000, compared to a human's 30,000 genes." Conventional breeding allows all these genes to recombine and segregate after each mating, putting positive pressure on about 20 to 50 genes. In contrast, genetic modification usually concentrates on one, or at most a few, genes at a time. Because of this, genetic engineering may in fact not be the best approach to solving some issues because there are many genes, for example, that influence yield and plants' responses to drought stress. "Where genetic engineering (genetic modification) really shines is where no genetic variation for a trait is known," Dr Barr told growers. "For instance, no resistance to Roundup was known in plants at the time Monsanto started working on its Roundup Ready® technology package." Other examples are resistance to take-all or Rhizoctonia, where conventional plant breeding has not been successful despite a large effort. Dr Barr said he was often asked whether genetic modification was faster than conventional breeding. "The answer is yes and no," he said. "The longest period for conventional breeding is finding the genetic variation for the trait of interest, understanding its genetic control and how to manage that trait in the breeding program. After these preliminary studies, the crossing and selection phase can now be done in about seven years." Genetic engineering's longest periods are consumed by the exploratory phase to find the genetic variation needed. "Then a great deal of effort goes into understanding its genetics so it can be isolated, cloned and prepared for its role in plant improvement. Once this phase is complete, its introduction into the target plant can be relatively fast. Results from this 'transformation' phase may be known in months and seed available for testing in two to three years. "Unfortunately, the transformation phase may damage the target cells and conventional breeding may be called on to correct problems, adding five years to the release." OCTOBER/NOVEMBER 2005 GROUND COVER Breeders take science to growers For centuries farmers have collected seed from the best-looking or highest- yielding plants, progressively breeding superior lines to the point that a modern cereal crop, for example, bears little resemblance to its ancestral grasses. Up until the Industrial Revolution, the rate of this progression was slow but adequate. Since then, the planet has been put under increasing human pressure and over the past 100 years, crops have needed increasingly sophisticated plant-breeding science to cope with deteriorating growing conditions and increasing food demand. Today, plant breeders have a new tool, gene modification, which they believe will allow the next 'step-change' in agriculture's capacity to meet even harsher climatic, economic and environmental circumstances. As part of mounting grains industry concern about the politicisation of the science, more scientists are getting out into the field to talk to growers. Rebecca Thyer reports on a recent example, when the Eyre Peninsula Agricultural Research Foundation held a field day on 'Breeding Better Varieties' at Minnipa Also, Australia's regulatory authority, the Office for Gene Technology Regulation, must undertake testing to ensure the GM variety is "safe" for commercial production, adding more time to its release. GROWERS ASK FOR CHOICE FACTS AND FICTION Andy Barr's GM myth-busters "All GM crops will be owned by multinationals." Not true. Organisations like CIMMYT, CSIRO and the Australian Centre for Plant Functional Genomics are also involved in genetic engineering. "GM technology has no environmental upsides." Not true. It can reduce the sprayings needed in crops like GM cotton, which benefits land, wildlife and humans. "GM is the only way to solve hard problems." Not true. Conventional breeding can also be used. Instead, GM forms part of a package of options. n Maree McKay and her husband Wayne, who produce wheat, canola, beef and prime lambs on a dryland farm in central-west NSW, are founding members of the Producers' Forum, a grower group set up to try to secure choice over whether or not farmers grow crops bred with gene modifications. Mrs McKay says the NSW moratorium on the commercial cultivation of GM food crops, which ends in March next year, has stopped producers from having a right to choose. "We want to see producers having the option of using this technology if it's suited to their farming system," Mrs McKay says. "That would allow farmers to continue to do what they normally do: look at the technology, see if it's suited to them, and then decide whether to adopt it or not." There is a concern among producers that research is slowing down because "there's no way forward", she says. Producers' Forum convenor Jeff Bidstrup, from Warra in south-east Queensland, says: "I've seen the massive impact that GM has had on the cotton I produce. And as a graingrower as well, I feel we can't just give away a 20 to 30 per cent yield advantage." He says the worldwide introduction of GM cotton caused production to surge and prices to drop, and this scenario threatens the grain industry: "We have the option of competing equally, or with one hand tied behind our backs." For more information: Producers' Forum, firstname.lastname@example.org Andy Barr "So the first variety may be very slow to develop, sometimes more than 15 years, but subsequent varieties may be faster because the exploration phase is not required," Dr Barr said. Founding members of the Producers' Forum: Maree McKay and husband Wayne.
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