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Another breakthrough for breeding drought tolerant wheat by researchers from The University of Western Australia will improve yield in dryland agriculture.For the first time, genome regions controlling grain number per spike under water stress have been identified, and suitable molecular markers for breeding programs have been developed.

Drought frequently reduces grain yield in Mediterranean-type climates in southern Australia. In drought years, water stress can cause up to 50 per cent yield reduction compared to favourable seasons.

Lead researcher Professor Guijun Yan from UWA’s School of Agriculture and Environment and Institute of Agriculture said the most intense effects on yield have been recorded when water stress coincides with the period between the onset of meiosis and early grain development.

“In the Western Australian grainbelt, water stress occurs often during meiotic stage, resulting in fewer grains per spike,” Professor Yan said.

In a companion study, the researchers revealed that both the male and female reproductive parts of the wheat plant are sensitive to water stress during meiosis, not just the male part as was previously thought.

Professor Yan said the yield reduction caused by water stress during meiosis resulted in fewer grains per spike, but had no significant reduction in mean grain weight.

“Building on from the previous research, we have now identified the chromosome regions and genes associated with grain number under water stress,” Professor Yan said.

“This research has an immediate application for commercial wheat breeding programs as the favourable genes identified can be crossed to make more drought-tolerant germplasm and increase grain yield.”

The paper, Identification and validation of a major chromosome region for high grain number per spike under meiotic stage water stress in wheat (Triticum aestivum L.) was published in the journal PLoS ONE .

The publication formed part of the PhD research of Dr Ifeyinwa Onyemaobi who was supervised by UWA Professors Guijun Yan, Kadambot Siddique and Dr Helen Liu.

Media references

Professor Guijun Yan (The UWA Institute of Agriculture and School of Agriculture and Environment) (+61 8) 6488 1240

Diana Boykett (Communications Officer, The UWA Institute of Agriculture) (+61 8) 6488 3756 / (+61 4) 04 152 262