Transfer of Fusarium Head Blight Resistance from Thinopyrum Elongatum to Bread Wheat Cultivar Chinese Spring.

The diploid form of tall wheatgrass, Thinopyrum elongatum (Host) D.R. Dewey (2n = 2x = 14, EE genome), has a high level of resistance to fusarium head blight. The symptoms did not spread beyond the inoculated florets following point inoculation. Using a series of E-genome chromosome additions in a bread wheat cultivar Chinese Spring (CS) background, the resistance was found to be localized to the long arm of chromosome 7E. The CS mutant ph1b was used to induce recombination between chromosome 7E, present in the 7E(7D) substitution and homoeologous wheat chromosomes. Multivalent chromosome associations were detected in the BC1 hybrids, confirming the effectiveness of the ph1b mutant. Genetic markers specific for chromosome 7E were used to estimate the size of the 7E introgression in the wheat genome. Using single sequence repeat (SSR) markers specific for homoeologous wheat chromosome 7, introgressions were detected on wheat chromosomes 7A, 7B, and 7D. Some of the introgression lines were resistant to fusarium head blight.