Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/24/1996
Publication Date: N/A
Interpretive Summary: Durum wheat has been a valuable source of genes for Hessian fly resistance that can be readily transferred to common wheat varieties. The durum wheat Plant Introduction (PI) line 422297 is of particular interest to wheat breeders because it is the source of the resistant gene H19, and possibly a second gene, that could be utilized in developing wheat varieties with improved Hessian fly resistance. Research was conducted to determine whether it differed from genes presently identified from other durum wheat lines. Tests using standard wheat breeding procedures were conducted to determine the genetics of resistance in PI422297 and to separate genes on the basis of response to specific Hessian fly races (biotypes) and different temperatures. Results demonstrated that two genes were present in PI422297 and that the second gene was different than previously identified genes from durum wheat. The second gene was designated H27 to denote that it was unique from other named genes. H27 may be of particular value in breeding wheat varieties for resistance to new Hessian fly biotypes that can attack wheat plants carrying many of the previously identified resistance genes.
Technical Abstract: The durum wheat (Triticum turgidum Desf.) line PI422297 has been reported to carry two genes that condition resistance to Hessian fly, Mayetiola destructor (Say) biotype L. gene H19 and an unnamed gene that is closely associated with gene H16. It is useful to identify the effects of genes that confer host resistance in parental source lines for wheat improvement. Our objectives were to determine the effectiveness of H19 and the second gene of PI422297 to biotype L at several temperatures. Gene H19 was transferred from PI422297 to susceptible durum wheat line D6647 to separate H19 from other genes and to compare it with the other resistance gene in PI422297. Durum wheat lines homozygous for H19 were developed by identifying segregating backcross F2 families and pedigree selection. In the F5 generation, lines homozygous for H19 were identified from testcrosses involving durum wheat line IN80164 (H16H16). Nearly all seedlings of the homozygous H19 lines were resistant at 19 degrees C, only 42 of 66 percent were resistant at 23 degrees C, and none were resistant at 26 degrees C. All, 89 percent, and 15 percent of PI422297 seedlings were resistant at 19, 23, and 26 degrees C, respectively. All seedlings of line IN80164 (H16H16) were resistant at 19 and 23 degrees C and 84 percent were resistant at 26 degrees C. Thus, the second gene in PI422297 is not H16, and it is tentatively designated as H27.