Breeding high-tech cotton

Helicoverpa Armigera, also known as Heliothis or cotton bollworm, is a voracious cotton pest that can cause widespread damage if not kept under control.

Heliothis feed on leaves, flowers and developing cotton bolls.

In the past, Australian cotton growers used insecticide sprays to control the pest, but yield losses were still substantial and chemical inputs high.

By the 1980s, cotton had become a major export earner for Australia, but its heavy dependence on chemicals saw its sustainability increasingly called into question.

Genetic modification (GM) technologies that were emerging in the late 1980s offered scientists a way to make the cotton plant itself produce a protein that was toxic to the heliothis, rather than having to rely on insecticides.

Classical plant breeding to select and enhance desirable characteristics has been going on for hundreds of years.

Biotechnology offered a more precise way to select desired traits. It allowed the breeder to select and insert the gene only for a specific trait.

At the CSIRO, scientists Dr Greg Constable, Dr Danny Llewellyn and Dr Gary Fitt and their teams pioneered the introduction of an insecticidal gene – named Ingard® – into Australian cotton in the early 1990s.

Ingard® varieties express the Bt (bacillus thuringiensis) protein to protect themselves against insect attack.

Bt is a naturally occurring, soil-dwelling bacterium commonly used as a biological pesticide.

Together with their third-party providers, Drs Constable, Llewellyn and Fitt and their teams’ skills across plant breeding, molecular biology, entomology and ecology allowed them to rapidly establish a world-class GM cotton breeding program.

In record time, over four years, they and their seed company partners developed the first commercial cultivars of GM insect-tolerant cotton.

When Ingard® cotton was released in 1996, it was rapidly adopted by the Australian industry.

Growers immediately recognised the benefits of a high-quality cotton variety that required far fewer insecticide applications.

After six years Ingard® was replaced by a superior two-gene product (Bollgard® II) with in-built resistance management properties.

Pesticide usage in Bollgard® II cotton was reduced by 80% each year – better for the farmer and for the natural environment.

The use of GM crops in Australia is heavily regulated by government under a national scheme called the 'Gene Technology Regulations' to ensure the technology is well managed for potential issues such as resistance.

On average, each new cotton biotechnology variety takes 13 years and $130 million of research, development, field trials and regulatory approval before coming to market.

Safety assessments are also conducted by 20 to 40 independent health and environmental agencies worldwide.

For GM cotton to succeed in the long term, it has been necessary to implement measures to prevent pests of cotton from developing resistance to the Bt toxin.

The cotton industry’s Resistance Management Plan includes five measures farmers must take, such as the planting of refuge crops, and now forms part of the licensing conditions for growers using these technologies.

Trends with industry pesticide use indicate growers are becoming more familiar and confident in the management of their crops.

Yields continue to rise, so the overall farming system is becoming more efficient as well as more environmentally friendly.

Resistance Management Plans are understood and adopted by cotton growers, and the time they save managing crop pests has allowed them to invest in other on-farm improvements, leading to the lean and responsive industry we have today.

Today 99.9% of Australia’s cotton crop is grown with varieties containing biotech traits and our scientists are continuing to develop new varieties uniquely adapted to Australian conditions.