Cytogenetical Studies in Wheat VIII. Telocentric Mapping and Linkage Studies Involving Sr22 and other Genes in Chromosome 7AL

The gene Sr22 conditioning low reaction to Puecinia graminis tritid was located by telocentric mapping on chromosome 7 AL at 27 � 4 crossover units from the centromere. Sr22 was approximately 2 crossover units from en-AI (ehlorina) and 41 units from PmI for low reaction to Erysiphe graminis trifid; however, the order of Sr22 and en-AI relative to PmI was not resolved. Maximum recombination between PmI, Lr20 and SrI5, for low reactions to E. graminis tritici, P. reeondita and P. graminis tritid respectively, was estimated to be O' 3 crossover units at the 95 % probability level.