Breeding Focus On Dryland Cotton Varieties

03 December, 2002

Dryland cotton growers are expected to receive major benefits from the new dryland variety breeding program being undertaken by CSIRO at the ACRI at Narrabri.

__Chief dryland cotton breeder, Dr Warwick Stiller (Pictured right), told delegates to the first Dryland Cotton Workshop held at Sanctuary Cove last week, that better and more consistent dryland varieties are in the pipeline.

However, he explained to the Workshop, organised by the Australian Cotton Research Centre and Cotton Seed Distributors, that it could take up to eight years before a dryland-specific suite of varieties is ready for commercialisation.

The increased emphasis on breeding dryland varieties stems from significant expansion in dryland cotton in recent years.

Dr Stiller told the Workshop the area planted to dryland cotton had increased from minor acreage 15 years ago to above 24 per cent of the area planted in 1998-99, which was equivalent to 131,000 hectares.

“It is estimated that in the long term, approximately 20 per cent of the cotton acreage in Australia will be dryland. This will vary from year to year, depending on price and planting rains,” he said.

He said CSIRO commenced a project in 1995 to determine the characters that constitute a good dryland variety, and the possibility of selecting for these characters in the early stages of a breeding program.

Initial dryland trials conducted by CSIRO found that okra leaf types exhibited improved water use efficiency, and that this translates into higher lint production per unit of water.

This has now led to a breeding focus on varieties capable of extracting all the available water, and also making the most efficient use of that water, and being able to repeat high yield performances over a number of seasons with differing rainfall patterns.

The CSIRO dryland breeding program also includes selection for disease tolerance, and also varieties with inherently long fibre and stable, mid-range micronaire to minimise the risk of discounts.

While shorter season varieties are not being ignored, the major focus is on full season varieties because of their ability to develop more beneficial root, fruiting and vegetative systems to handle the variable rainfall patterns across dryland cropping regions.

“For every day delay in crop maturity (due to later maturing varieties) there is on average a 34kg lint/ha increase in yield,” Dr Stiller told the Workshop.

Further Information: *"Robert Eveleigh**, John Marshall, Greg Kauter or Craig McDonald":showstaff.asp?staff=1