Date: 3/29/99

Time: 4:05

Type: Symposium

Number: 40

Maintaining plant resistance as a major component in pest management systems for the Hessian fly

*R.H. Ratcliffe, USDA-ARS, Crop Production and Pest Control Research Unit, and Department of Entomology, Purdue University, West Lafayette, IN 47907 and C. Williams, USDA-ARS, Crop Production and Pest Control Research Unit, and Department of Entomology, Purdue University, , IN 47907
Contact e-mail: roger_ratcliffe@entm.purdue.edu

The Hessian fly remains a serious threat to wheat production in the eastern U. S. soft winter wheat region, although it has been managed effectively in much of this area by growing resistant wheat cultivars. However, fly populations are continually adapting to resistant cultivars, necessitating the development of new sources of resistance for use in future breeding programs. Selective use of new resistance genes based upon an understanding of changes occurring in Hessian fly populations, and the combination of different genes in new wheat cultivars by means of both conventional and molecular-based breeding methods, will be required to improve the durability of resistance in cultivars in the future. Hessian fly populations from 18 states in the eastern U. S. soft winter wheat region have been studied extensively since 1989 to monitor changes in biotype composition and to evaluate the effectiveness of new resistance genes identified in the USDA/Purdue program. Concurrently, research to identify molecular markers associated with resistance genes has been undertaken in order to develop more efficient and dependable methods for pyramiding genes in wheat cultivars. Research has resulted in identification of two markers that are associated with a unique (new) gene that is effective against virulent fly populations from the mid-western and southeastern U. S., and the markers have been cloned and adapted for use in the wheat-breeding program. The application of research accomplishments to date with efforts to pyramid genes for Hessian fly resistance in future wheat cultivars will be discussed.

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