September 3, 2003

Black spot disease has limited Australia’s adoption of field pea where it would boost soil nitrogen, provide a disease break and help control weeds to lift subsequent wheat crop yields by five per cent.

Field pea’s broad soil adaptability and relative drought tolerance would make it a perfect legume fit for 400,000 hectares across southern Australia, but black spot cuts into the crop’s $260 per tonne grain yield by 20 – 40 per cent.

The Grains Research and Development Corporation (GRDC) is therefore supporting a University of Western Australia PhD student, Cameron Beeck, who is now field testing resistant pea lines which combine several genetic sources of black spot resistance.

“Minor resistance genes pyramid when brought together to provide combined strength. The challenge is to accumulate those different genes and successfully transfer them into new lines” Mr Beeck explained.

“To do this, we’re cycling through several field pea generations and pursuing different sources of genetic resistance. When we’ve refined those resistances we’ll attempt to bring them together in one new line.”

This process is known as ‘rapid cycling’ and although complex to manage, it saves time by condensing several breeding goals into one timeframe.

To make further use of rapid cycling efficiencies, Mr Beeck and the GRDC research team, including supervisors Janet Wroth, Associate Professor Wallace Cowling and Dr Tanveer Khan, will use the process to simultaneously increase the stem strength of new black spot resistant lines, making them easier to harvest.

Once candidates with increased black spot resistance and stem strength are developed, those qualities will be combined and the best lines provided to Australian field pea breeders to test in multi-environment trials or to cross with commercial cultivars.

The lines being assessed in the GRDC project came from inter-crosses between current commercial varieties, interspecies crosses by Dr Wroth and Greek land races collected by Professor Clive Francis of the Centre for Legumes in Mediterranean Agriculture.