Abstract
Powdery mildew resistance of Amigo wheat [Triticum aestivum] has been analyzed and mapped by combining F2 segregation data with cytogenetic and storage protein analyses. It is concluded that the powdery mildew resistance of Amigo is regulated by one gene with conditioned dominance. Cytogenetic and electrophoretic analyses revealed that the complete wheat chromosome are 1AS is missing in Amigo and has been replaced by the rye chromosome arm 1RS. No susceptible recombinant was found among 1,034 F2 plants of crosses of Amigo with Pm3 resistance lines; Pm3 is known to be located on 1AS. Thus, the powdery mildew resistance gene of Amigo is assumed to be located on the rye chromosome 1RS translocated to wheat chromosome 1AL. The resistance pattern of Amigo is different from that of lines carrying gene Pm 8. Free segregation of the Amigo resistance gene and Pm8 (located on 1RS of 1RS .cntdot. 1BL translocations) occurred. On the basis of these results, we propose the gene symbol Pm17 for the Amigo powdery mildew resistance gene.