Characterizing disease and pest resistance introgressed from related species into wheat
Host-plant resistance to diseases provides yield and quality protection to all economically important crops. The diversity of resistance to certain diseases and pests that is available in cultivated wheat ( Triticum aestivum L.) is limited; therefore, new sources of resistance must be identified and used in commercial varieties. Certain grass species that are related to wheat provide resistance that is transferable to wheat. Hessian fly (HF)-resistance, from durum wheat (Triticum turgidum L.), in the wheat line 97211H2-1-8-8-1, protects against all tested Hessian fly (Mayetiola destructor [Say]) biotypes and populations. This HF resistance is conditioned by two genes in complementary epistasis, one gene that is ineffective by itself and a second gene that is partially effective against certain biotypes of HF. The fusarium head blight (FHB)-resistance QTL, Qfhs.pur-7EL, from tall wheatgrass (Thinopyrum ponticum) was introgressed onto the long arm of wheat chromosome 7D. Two yellow dwarf virus disease (YD)-resistance genes, Bdv2 from chromosome 7St and Bdv3 from chromosome 7E, were independently introgressed from intermediate wheatgrass (Thinopyrum intermedium) onto the long arm of wheat chromosome 7D. Qfhs.pur-7EL and Bdv3 were combined in coupling, providing resistance to two important diseases of wheat, and these two resistance factors will remain in coupling in wheat. Bdv2 was moved to wheat chromosome 7B, which will enable combining Bdv2 and Bdv3 in wheat, potentially increasing the level of YD-resistance similar to that in intermediate wheatgrass. These examples demonstrate the importance of characterizing and introgressing disease- and pest-resistance from related species into cultivated wheat.
Ohm, Purdue University.
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