THE INHERITANCE OF LEAF RUST RESISTANCE IN FOUR COMMON WHEAT VARIETIES POSSESSING GENES AT OR NEAR THE Lr3 LOCUS
The inheritance of seedling resistance to leaf rust was studied in the wheat varieties Democrat, Sinvalocho, Bage and Klein Aniversario and in the backcross lines developed from them. The Lr3 gene from Democrat and Sinvalocho conferred resistance to races 1, 9 and 11. Genetic analysis of the Sinvalocho × Prelude0 line (with Lr3), using a rust culture that was avirulent on Democrat × Thatcher6 and Sinvalocho etc., but virulent on Sinvalocho × Prelude6, indicated the presence of a suppressor gene in Prelude. The variety Bage has two genes for resistance to races 9 and 11, one giving a 0; reaction and the other a type 2. The former gene was present in Bage × Thatcher8 and was allelic to, or closely linked with, the Lr3 gene. It is temporarily designated Lr3bg. Klein Aniversario may have two independently inherited genes conferring resistance to race 11 and two to race 161. One of the genes conferred resistance to both races and was transferred to Thatcher and Prelude. This gene was also allelic to, or closely linked with, the Lr3 gene and is designated Lr3ka. These results suggest a complex Lr3 locus with a series of alleles or closely linked genes.