Submitted to: International Congress of Plant Pathology Abstracts and Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 5/12/1998
Publication Date: N/A
Citation: Interpretive Summary:
Technical Abstract: Barley yellow dwarf virus (BYDV) is the most economically important virus pathogen of wheat but resistance to BYDV does not exist in wheat. A wheat line (P29), in which the 7D chromosome has been substituted with a 7E chromosome from the BYDV resistant wheatgrass Thinopyrum intermedium, was previously shown to contain some resistance to BYDV. In this study further analyses demonstrated that the complete resistance to subgroup I BYDV strains possessed by the wheatgrass has not been introgressed into P29. In contrast, P29 was completely resistant throughout the plant to the BYDV subgroup II strains. Because P29 is a substitution line containing an entire wheatgrass chromosome it is not suitable for breeding for BYDV resistance. Consequently, this line was irradiated to induce chromosomal translocations as a means of retaining BYDV resistance while reducing the amount of alien chromatin. The standard phenotypic analysis approach resulted in a very low success rate of identifying BYDV resistant and susceptible translocation lines (4.0%). We developed an alternative approach by initially identifying BYDV susceptible deletions lines with a repetitive sequence specific to the alien chromosome, followed by comparative genome analyses of their resistant sister lines. This approach was more effective in identifying resistant translocation/deletion lines and also localized the BYDV resistance to the distal end of 7EL. Resistant translocation lines identified from this study are now being used as germplasm for incorporating BYDV resistance into elite wheat lines. Development of a unique strategy for efficiently identifying translocation lines will significantly enhance the introgression of alien genes into crop plants in the future.