Cotton breeding and new cotton varieties

Cotton has been grown in Australia since the 1800s, but production was small and variable until the modern irrigated industry developed in the 1960s in southern Queensland and northern NSW. The expansion of the modern industry was based at first on varieties from the USA but since the first releases of blight-resistant varieties developed by Norm Thomson in the early 1980s followed by the fungal resistant varieties developed by Peter Reid, CSIRO cotton varieties have come to dominate the Australian market.

CSIRO varieties have revolutionised yield, fibre properties and disease resistance in Australia and had large impacts in a number of other countries. Since 1984 new CSIRO cotton varieties have increased yield by two per cent per annum in Australia and growing regions have been extended in NSW and Queensland. Australia has the highest cotton yields in the world and CSIRO varieties are a key component of this system. The introduction of transgenic cotton varieties with insect and herbicide resistance has helped to revolutionise cotton growing in Australia with major reductions in pesticide use (see Cotton pest management ).

The Australian cotton industry – problems and potential

While cotton has been grown in Australia since the 1800s, production was small and variable until the modern irrigated industry developed in the 1960s in southern Queensland and northern NSW. There was also a brief boom of the modern industry in the Ord Valley in northern Western Australia during the 1960s but insect control problems led to the demise of the industry there in 1973. Norm Thomson worked for CSIRO in the Ord during this period and his experience there influenced his approach to cotton breeding when he moved to Narrabri in 1972 as part of CSIRO consolidating all cotton breeding to one location. Norm was joined by Peter Reid in 1979.

Insect pests, particularly Helicoverpa armigera, were a constant challenge in the eastern Australian industry and other problems which soon became evident were diseases such as the fungal infection Verticillium Wilt and Bacterial Blight. The original USA varieties as well as being susceptible to insects and diseases had less than desired fibre quality.

Thus Norm Thomson commenced a cotton-breeding program at Narrabri with major strategic aims to rectify the limitations of the USA varieties. In terms of insect resistance he experimented with many morphological and biochemical resistance characters. The most successful of these was the okra leaf shape which has narrow leaflets in contrast to the broad normal leaf. The more open canopy results in a less favourable environment for insects and enables some reduction in pesticide use. The okra leaf character also gives a small improvement in water use efficiency.

The range of environments in the cotton industry meant that the breeders aimed to develop varieties with specific adaptation to the different growing areas. Norm Thomson concentrated on fuller season areas and Fred Gillham and Peter Reid focused on shorter season areas and late plantings.

First breakthroughs: the blight-resistant varieties Siokra and Sicala

A major breakthrough from Norm’s program was the release in 1985 of the variety Siokra 1-1. This was the first okra leaf variety to be widely grown anywhere in the world. As well as the okra leaf shape Siokra had excellent fibre quality and was also resistant to the serious disease bacterial blight. This started a long line of fully blight resistant varieties from CSIRO and has resulted in the elimination of bacterial blight from the Australian cotton industry.

In 1987 the release of Sicala 3-1 brought a further advance in fibre quality and the Sicala name soon became synonymous with high quality Australian cotton. Further releases flowed from Norm’s program including the very successful Siokra 1-4 and CS 50. CSIRO varieties soon gained a large market share in Australia and have dominated for most of the period since despite strong competition from Deltapine, a large USA cotton breeding company, which established an Australian operation. Seed of CSIRO varieties is produced and marketed by Cotton Seed Distributors (CSD), a grower controlled company which also developed an overseas operation, Cotton Seed International (CSI), to market CSIRO varieties overseas.

Further breeding successes: cotton varieties with high fungal resistance

The first major releases from Peter Reid’s program were the first Australian varieties with strong resistance to Verticillium Wilt, Sicala V-1 (1991) and Sicala V-2 (1994). These varieties, particularly Sicala V-2, were very widely grown in Australia and became very successful in overseas markets.

Impact – Australia’s cotton industry transformed by CSIRO’s research

The modern cotton industry which emerged in the 1960s and 1970s at first had a system which produced relatively low yields and mediocre fibre quality while having a constant war with insects and weeds using many chemicals. Through scientific research and also innovation from farmers, the industry has been transformed to one with the highest yields in the world, excellent fibre quality and with a much reduced reliance on pesticides.

Cotton now forms a key part of rural communities in the belt from the Murrumbidgee Irrigation Area (MIA) in southern NSW to Emerald in central Qld. Drought and low cotton prices in the late 1990s forced growers to seek varieties with the highest yield, per ha and per megalitre of water, and fibre quality expected by spinners. CSIRO bred varieties have strongly assisted the industry during this period and the variety Sicot71BRF represented a special case with unprecedented uptake and success since its release in 2009. Articles describing the impact of CSIRO cotton varieties are as follows:

• Johnston B, Healy T, I’ons J, McGregor M, 1992, ‘Rural Research —the pay-off: The returns from research undertaken by the CSIRO Institute of Plant Production and Processing’, CSIRO and ABARE, Canberra.
• Constable GA, Thomson NJ, Reid PE, 2001, “Approaches utilized in breeding and development of cotton cultivars in Australiaâ€. In: Genetic Improvement of Cotton: Emerging Technologies.Jenkins JN and Saha S (Eds). Science Publishers, Enfield. pp 1-15.
• Anon, 2002, ‘Cotton breeding and decision support. A benefit-cost analysis of CSIRO’s research programs’. Centre for International Economics. Canberra and Sydney. 32pp.
• Constable GA, 2009, ‘Breeding as a business – return on R&D investment in crop improvement’. 14th Australasian Plant Breeding Conference and 11th SABRAO Congress, Cairns, 2009.

Awards and Recognition

The CSIRO cotton breeding program has been recognized by the following awards.

Source

• Reid PE, 2010, Personal communication.
• Constable GA, 2012, Personal communication.