Durable resistance to leaf rust and stripe rust of wheat

Dr Grant Hollaway (VDPI, Horsham), Dr Garry Rosewarne (GRDC Postdoctoral Fellow, CIMMYT), Dr Ravi Singh (Principal Scientist, CIMMYT) and Dr Julio Huerta-Espino (Senior Adjunct Scientist, CIMMYT) inspecting a wheat stripe rust nursery at Toluca, Mexico.

THE WHEAT breeding program at CIMMYT has emphasised the use of adult plant resistance (APR) for rust control for almost 30 years. Genetic analysis of cultivars carrying APR has shown that accumulating up to five genes with minor but additive effects against leaf rust and stripe rust confer high levels of durable crop protection. Over the past 12 years, CIMMYT's Rust Resistance Program, led by Ravi Singh and recently with assistance from Garry Rosewarne, an Australian GRDC Postdoctoral Fellow, has developed an understanding of the genetic basis of this resistance by identifying, mapping and designating resistance genes. This information has in turn assisted wheat breeders in selecting for such resistances. More recently, a program to identify molecular markers linked to these genes was also initiated under the Cooperative Research Centre for Molecular Plant Breeding. The resistances being characterised are being incorporated into important cultivars and widely adapted lines and will be assessed under Australian conditions by ACRCP staff.

The use of CIMMYT germplasm has provided great benefits to the Australian wheat industry. The germplasm carrying diverse APR genes, and associated information, as well as the methodology used in the selection of APR, will enhance the capability of wheat breeding programs in Australia to develop durably resistant cultivars. In turn, this will enable Australian farmers to avoid major rust epidemics and to protect their grain yield and grain quality.

Program 3 Contact: Dr Ravi Singh email r.singh@cgiar.org