|Ohm, H - PURDUE UNIVERSITY|
|Sharma, H - PURDUE UNIVERSITY|
|Patterson, F - PURDUE UNIVERSITY|
|Obanni, M - PURDUE UNIVERSITY|
Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 1, 1995
Publication Date: N/A
Interpretive Summary: The Hessian fly is a serious insect pest of wheat world-wide and is controlled primarily by growing resistant wheat varieties. Twenty-six genes in wheat have been identified that confer resistance to one or more races (biotypes) of the Hessian fly, but only four genes have been used extensively in wheat varieties to date. It is important to determine how recently-identified resistance genes are associated physically on wheat chromosomes in order to use them most effectively in developing new wheat varieties. This paper reports research to determine the relationship of seven Hessian fly resistance genes that have been identified on wheat chromosome 5A. Genetic tests indicated that six of the seven genes are closely linked in a restricted area (block) on chromosome 5A while the seventh gene is outside of this chromosome region. None of the genes appear to be so close to one another, however, to prevent their separation and recombination in wheat germplasm by breeding methods. This manipulation of resistance genes would enable development of wheat varieties that carry several resistance genes, but in different combinations, that would provide the most effective control of Hessian fly populations found in specific regions of the eastern United States.
Technical Abstract: Hessian fly [Mayetiola destructor (Say)] is a serious pest of wheat (Triticum ssp.) in many wheat growing areas of the world. A number of genes (H1-H26) that confer resistance to Hessian fly have been described. The linkage relationships of many of these genes, which are useful in breeding wheat for resistance to Hessian fly, are unknown. Testcross analyses were made in tetraploid durum wheat (Triticum turgidum L.) and tested to biotype D of Hessian fly to determine the linkage relationships among genes H9, H10, H12, H14, H15, H16, and H17, all conferring resistance to biotype D. Also, monosomic 5A plants of susceptible cultivar Chinese Spring were crossed as seed parents to Purdue wheat (T. aestivum L. em Thell.) lines carrying gene H10 or H12. Testcross analyses indicated that six of these genes appear to occupy a single linkage block on wheat chromosome 5A in the order H9, to H15, H10, H17, H16, and H12. Gene H14 did not appear to be within the linkage block H9 to H12. Additionally, F2 plants derived from 41-chromosome F1 plants and F3 families derived from F2 resistant plants were tested against biotype D. F2 segregation deviated significantly from 3 resistant : 1 susceptible and F3 families from resistant F2 plants derived significantly from 1 resistant : 2 segregating for both crosses involving H10 and H12. Thus, monosomic analyses provided additional evidence that genes H10 and H12 are likely on chromosome 5A. Linkage between these genes would not seriously limit efforts to pyramid them in breeding for resistance to the Hessian fly because the linkage values are more than 20 centimorgans.