Plant breeders are well aware of fibre quality issues in Australian cotton, and the country's top breeder, Dr Greg Constable, pictured, outlined the CSIRO breeding team's fibre quality targets at a recent conference.

Dr Constable spoke at the Australian Cotton Shippers Association conference, held on the Gold Coast, September 3-6, 2003. The theme of the conference was “accent on quality”.

The principal CSIRO plant breeder (CSIRO varieties currently comprise the majority of the Australian crop) told the conference that CSIRO fibre quality targets were as follows:

Strength: 30gt/tex
Length: 1.15 inches
Uniformity: High (low neps)
Micronaire: 3.8 – 4.4
Low Neps

He said fibre quality was affected by many factors including climate, varieties and management, and the best result came from getting all these right, not just one element.

Dr Constable noted that from 1990 onwards there has been a big improvement in length aspects, but this has now plateaued. He said strength had been improving since 1980, and there was material in the breeding pipeline capable of producing 35g/tx, well in excess of current requirements.

However, micronaire changes have been minimal due to the negative association between fineness and yield, and the breeder’s emphasis on yield in response to grower demand flowing from the positive economic benefits of yield improvements.

He said neither variety nor Bt transgenics could alone explain trend towards higher micronaire, arguing that climate and management are responsible for the variation in micronaire between seasons, particularly high temperatures, clear skies, and low insect pressure.

He suggested that Bollgard cotton may lean toward higher micronaire when weather conditions favour fibre thickening, and when the plant produces more bolls on the bottom of the plant due to lower insect pressure.

While acknowledging that yield levels and stress patterns will affect micronaire, he said low micronaire could still result from cool seasons in southern areas, and cloudy season in all areas, particularly in January. He said there are opportunities to manage the crop to optimise fibre quality, particularly in relation to irrigation, insect management and defoliation.

Overall, however, Dr Constable’s presentation seemed to explode the popularly paraded myth that the demands of end users are moving much faster than the capacity of breeders to comply or catch up.

Breeders could make even faster gains when and if research on DNA markers reaches fruition, enabling plant breeders to speedily identify genes for fibre quality traits in conventional varieties, slashing the time taken to identify and breed for improved traits.

Allan Williams, ACGRA executive officer, described how there are multiple influencers of fibre quality, which he described as an holistic issue, with no silver bullet solution.

He said the issue required consideration by a representative industry body, supported by credible industry data, industry agreement on priorities, goals, guidelines and an action timetable, accompanied by a formal extension and education program.