Australia Pursues Black Spot Resistance

SYDNEY - Apr 7/10 - SNS -- Australian ield pea varieties should be released with significantly improved black spot resistance in coming years as a result of world-leading research funded by the Grains Research and Development Corporation (GRDC) and its research partners.

Black spot (Ascochyta blight) is the most damaging disease in field peas in Australia. Pulse Breeding Australia (PBA) has made considerable progress in developing field pea lines with moderate resistance levels.

Much of this work is being performed in Western Australia, which has been identified as a primary site for genetic enhancement of black spot resistance in field peas.

Field pea lines with improved resistance developed by the Department of Agriculture and Food (DAFWA) are being incorporated into crosses by the PBA breeding program led by Tony Leonforte of the Department of Primary Industries in Victoria. Selected lines are being tested in national yield trials.

DAFWA plant breeder Kedar Adhikari said black spot can cause yield losses as high as 30% in Australian field pea crops.

To minimise the disease, growers are forced to undertake management practices such as late sowing – which results in further yield losses - and adjust crop rotations.

Dr Adhikari said some lines developed in the breeding work look particularly good. "They will undergo more testing and could become commercially available in a couple of years.

"Some lines have slightly higher yields and significantly better resistance than the popular variety Kaspa."

Dr Adhikari said resistance levels achieved in the Australian breeding work are world leading. The progress made is also significant given the challenges involved in the research.

"Black spot disease in field peas is quite difficult to breed for as many genes are involved in resistance to black spot – it is like making rope using different small threads," Dr Adhikari said.

"To transfer this resistance requires time and many backcrosses because you need to build up a number of genes.

"The other problems are that there are low levels of resistance available in the germplasm and more than one pathogen is involved in the disease.

"In spite of these difficulties, PBA has developed quite a few field pea lines with black spot resistance."

GRDC western panel deputy chairman Richard Oliver, whose GRDC program area is pre-breeding, said improvements to black spot resistance in field peas are desperately needed.

"Improved resistance to black spot will really open up field peas as a break crop option over a larger area of the western and southern regions of Australia," he said.

Professor Oliver said varieties with improved black spot resistance will allow growers to plant field peas earlier and achieve better yields.

"Currently growers plant field peas late to dodge the main period when the pathogen is active," he said.

"If growers can plant field peas earlier, it will result in a huge boost to yields."