Drysdale: Graingene's first 'drought-proof' wheat by Alec Nicol
GroundCover™ Issue: 46
DRYSDALE, A variety bred to use water more efficiently, will get wider testing this year.
This follows a tough start at the height of the 2002-03 drought where the new variety had little chance to get established. AWB Seeds has now distributed widely across the country all 200 tonnes of seed it held.
Spokesman for the company, Roger Tripathi, says that it's seen as a replacement for Janz and will be tested in all of the wheat-growing areas this year, except Queensland and northern NSW. Released as a 'drought-proof' wheat, the company is anxious to stress that its transpiration efficiency should stand the variety in good stead in good years as well as bad.
Bred by CSIRO through Graingene, Drysdale) is the first of a suite of varieties selected for the way the plant exchanges carbon dioxide for water in the process of photosynthesis and growth. The basic science showed that plants take in carbon dioxide necessary for photosynthesis through their stomata but at the same time lose water by transpiration through those stomata. Drysdale is more efficient in the way it does this.
Less water used per unit of growth
The variety has been selected to lose less water per unit of carbon dioxide it takes up. This means less water used per unit of growth and more moisture left in the soil for grain filling.
Drysdale is the result of the high transpiration efficiency trait being incorporated in the variety Hartog, In a four-year trial over a wide range of sites, it demonstrated an average 5 per cent yield advantage over Hartog. That advantage was evident in yields of up to 7 t/ha and while the variety used less water per unit of growth in good years and bad, the yield benefit was most evident in situations where moisture stress was most severe. In drier conditions the yield advantage averaged 10 per cent more than Hartog.
Rated as an Australian Hard variety in southern zones, Drysdale will be received as an APW variety elsewhere, It has dough qualities similar to Janz and larger grain size than most current varieties. It is moderately resistant to all forms of rust and has the advantage of being tolerant to acid soils. It's expected to be joined next season by a variety known as Rees. Also featuring the transpiration efficiency trait, this variety is intended for northern NSW and Queensland and is tentatively graded as Australian Hard,
Seed is currently being multiplied under irrigated conditions and adequate supplies are anticipated for a 2004 release.