As summer rolls in after a dry winter, Western Australia's graingrowers are left to count the toll of a parched season, which pundits suggest will halve last year’s 10.8 million tonne harvest.

So, just what do growers need in their arsenal to combat dry seasons?

With support from growers and the Federal Government, via the Grains Research & Development Corporation (GRDC), researchers with CSIRO Plant Industry mixed and matched various plant characteristics to identify a ‘designer plant’ which could best handle the dry.

The ‘bronzed Aussie’ of the plant world would be a true local, able to stand up to long, dry days, without wilting or withholding yield as with less well-adapted varieties.

The GRDC project was prompted by findings that 40 per cent of Western Australia’s wheat production came from low rainfall zones, where yield increments from superior varieties and agronomy lagged behind the rest of the state.

The average yields had crept up by 5.6 kg per hectare per year from 1960 – 1990, a rate only one quarter that achieved over the same period in medium to high rainfall areas.

Project supervisor, Dr Tony Condon of CSIRO, worked with the Department of Agriculture to evaluate trial plant varieties expressing specific characteristics and determine which should be included in drought tolerant varieties.

Restricted tillering has often been associated with better dry weather performance and although those test varieties did not out yield their freer tillering cousins, they better preserved grain size during dry finishes. Plants incorporating high transpiration efficiency (TE) produce more total dry matter from the water absorbed and, the study showed, gave a yield advantage of 3-5 per cent. This response was stronger in the driest environments.

Plants with good early vigour made the most of early season moisture to increase their yield by up to 15 per cent over control varieties. Coupling good early vigour with high TE should give a more consistent yield advantage. Good establishment, which could encourage this early vigour, was helped by coleoptile length, which emerged from the study as another preferred quality for dry weather performance.

Lines developed during this testing process have been supplied to breeders and new GRDC backed efforts are underway to introduce these dry weather characteristics into current varieties.