EFFECTIVENESS OF WHEATGRASS-DERIVED BARLEY YELLOW DWARF VIRUS RESISTANCE AND IDENTIFICATION OF RESISTANT TRANSLOCATION LINES
JM ANDERSON1, DB BUCHOLTZ1, OR CRASTA2, A GREENE1, MG FRANCKI2, HC SHARMA2 and HW OHM2
1USDA-ARS, and 2Purdue University, Agronomy Department, 1150 Lilly Hall, W. Lafayette, IN 47907, USA
Background and objectives
Results and conclusions
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 transiocations as a means of retaining BYDV resistance while reducing the amount of alien chromatin. Following gamma irradiation and selfing, a standard phenotypic analysis approach resulted in a very low success rate of identifying BYDV resistant and susceptible translocation lines (4.0%). However, analysis of susceptible progeny of irradiated seed with a repetitive sequence, specific to the alien chromosome, quickly demonstrated a high rate of deletions in the introgressed alien chromosome (58%). A comparative RFLP analysis of susceptible lines containing alien chromatin, their resistant sister lines and other resistant lines showed that 36% of the progeny of gamma-irradiated seed had deletions in the alien chromosome. This approach of initially identifying BYDV susceptible deletions lines using an alien chromosome-specific repetitive sequence followed by comparative genome analysis of their resistant sister lines rapidly identified resistant translocation/deletion lines and localized the BYDV resistance to the distal end of 7EL. These resistant translocation lines are now being used as a germplasm source for incorporating BYDV resistance into elite wheat lines, Furthermore, the development of a unique strategy for efficiently identifying translocation lines will significantly enhance the introgression of alien genes into crop plants in the future.