Genetics and breeding for rust resistance in wheat

This project replaces an earlier one of the same name (8337) and continues the work to characterise new genes for resistance against rust diseases. These new sources of resistance will be incorporated into commercial wheats in Pakistan, India and Australia. China may enter the project at a later date, giving project scientists access to new sources of rust resistance from Chinese winter wheats.

The rusts are potentially the most damaging wheat diseases throughout the world, including Asia and Australia. The three different types of rustleaf, stripe and stemusually occur in different environmental conditions, but on rare occasions can occur simultaneously. This project is largely devoted to leaf rust, followed by stripe rust then stem rust.

The rust funguses are constantly changing. Rust control is achieved by selecting sources of resistance that are longer lasting and by planting a wide variety of wheats to buffer the effects of the constant change in the rusts. The research program therefore aims to understand the nature and extent of variability within rust pathogen populations and the genetic basis of rust resistance in the wheat cultivars currently grown in the three partner countries. Scientists will also study the genetic basis of resistance in potentially useful cultivars and genetic stocks grown in countries other than Australia, India, Pakistan and China.

Various newly-identified sources of adult plant resistance to leaf rust, together with certain sources of seedling resistance not yet widely used, will be transferred by backcrossing into a range of Indian and Pakistani wheats. At the end of the three-year project new lines with enhanced resistance will be distributed to national breeders, to make further selections in the light of their own requirements or to use as rust-resistant parents for further crossing programs.

The genetic studies of populations descended from a single seed, which commenced in the original project, will continue. Increasing emphasis will be given to building up agronomic stocks of useful descendants for distribution to breeders at CIMMYT, the international maize and wheat improvement centre, and in Australia.

A number of scientists and technicians from both India and Pakistan will have opportunities for 'hands-on' experience in Australia at some time during the project's three-year span, following the highly successful training program of the previous project.