Ground Cover Supplement : GC Supplement - Pulse breeding
GROUND COVER PULSE BREEDING 10 BREEDING / PATHOLOGY Three-pronged search for new lupin genes Incestuous breeding from a small number of wild type lupins has produced steady yield increases but new material is needed for sustained improvement By Bevan Buirchell THE PROGRESS IN breeding higher-yielding narrow-leafed lupins has been impressive. Over the past 30 years yields have more than doubled, but this has not been without cost -- the narrowing of the germplasm base. Indeed, only eight wild accessions have appeared in the pedigrees of modern varieties from the Australian lupin breeding program. The lupin breeders, with support from the GRDC through Pulse Breeding Australia, are working to increase the genetic diversity of material used in the lupin breeding program led by the Department of Agriculture and Food, Western Australia (DAFWA). With more genes to choose from researchers hope to deliver lupin varieties more able to challenge soybeans as a source of protein and to maintain the improvements in yield. Three sources of new germplasm are being searched: nwild types or exotic germplasm from gene banks; nadvanced breeding lines and varieties from other breeding programs; and nold varieties within the same breeding program. Although more than 100 wild types have been used in past crossing programs, few have yielded germplasm of value. However, the Australian Lupin Collection (ALC) lists 1252 accessions under the wild type/ landrace category, so there is still more than 99 per cent of the genetic variation available for exploration. Most of this material originates from the Mediterranean. Since 2001 a new approach has been taken to the introduction of wild material into the core breeding program. The crosses made in 2001 using new wild material entered yield trials in 2008. The yield from this material was very encouraging along with the integration of higher protein content. By working with international lupin breeders who may have investigated other wild types it is hoped that some steps in identifying and isolating new wild germplasm can be short-circuited. Further investigation into older varieties held in the Australian lupin breeding program may seem pointless. However, during traditional crossing beneficial characteristics can be left behind, resulting in their loss from the variety but not from the breeding program. Using modern breeding techniques, lupin breeders have located and combined 'lost' genetic material into modern higher- yielding varieties. In some cases the results have been surprising. Plant breeders have no control over the price of lupins but they are striving to develop varieties that return a better margin through reduced inputs and improved yield and quality, as well as increasing marketing opportunities. □ GRDC Research Code DAW00181 More information: Dr Bevan Buirchell, senior plant breeder, leader PBA lupin breeding program, DAFWA, 08 9368 3653, email@example.com Focused on a moving target Adaptation equals survival but in pathogens change can lead to breakdown in variety resistance By Rebecca Ford SUBSTANTIAL PROGRESS HAS been made in developing new chickpea varieties with resistance to the fungal disease ascochyta blight. However, like cereal rust, this pathogen is a moving target and requires constant monitoring. The isolate of Ascochyta rabiei that caused the epidemic in 1998 lacked genetic variation compared with strains found overseas. The combination of this pathogen with highly susceptible varieties, grown under stubble retained systems in tight rotation, exacerbated the severity of this outbreak. Despite improved variety resistance and better understanding of chemical and cultural control, a similar outbreak could occur. This is because the A. rabiei pathogen may be highly adaptive. A change in virulence could enable the pathogen to overcome currently relied on resistance genes. To help assess and manage the risk of future epidemics our work is monitoring the A. rabiei pathogen to identify if pathotype differences are occurring. Between 2009 and 2011 up to 250 isolates of A. rabiei will be collected and analysed per year. We are especially focusing on areas where new resistant varieties are being grown. To prevent the pathogen from evolving virulence to the current sources of resistance Predicted means for historical varieties 1997 to 2007 yield (t/ha) FIGURE 1 Since 1997 trials have compared and recorded the yield of lupin varieties released since the late 1960s 0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Year of release Uniwhite Uniharvest Unicrop Marri Chittick Geebung JindaleeA Illyarrie Yandee Danja Gungurru Warrah Yorrel Merrit Myallie Tallerack WongaA Tanjil Kalya Belara Moonah Quilinock MandelupA CoromupA JenabillupA The upper line (red dots) is the predicted mean average yield improvement for varieties containing the early flowering gene and the lower line (blue dots) relates to varieties with later flowering genes.
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