Inheritance of virulence of Puccinia triticina culture X47, the F1 of the cross 71-112 x 70-1

Abstract

Cultures 71-112 (SBD) and 70-1 (BBG) of Puccinia triticina were purified, crossed, and the resulting F1 culture X47 (LBB) was selfed to study the inheritance of virulence on several near-isogenic lines of Triticum aestivun. The phenotype of the parents, the F1 and ratios of F2 progeny were used to explain the inheritance of pathogenicity, Results of the F2 segregation from the reciprocal cross (70-1 x 71-112), labeled X59 (CBB), were compared to results of the current study. The F2 cultures in this study segregated as if single dominant genes conditioned avirulence on near-isogenic lines with Lr2a, Lr2c, Lr10, Lr17, Lr28, Lr29, and Lr33. The avirulence genes were independently inherited. Linkage was detected between pathogen genes p2a and p2c with p29. Two genes appeared to control virulence on near-isogenic lines with Lr3, Lr3c, Lr11, Lrl6, Lr21, Lr26, and Lr30. The F2 ratios could be explained by classical gene-for-gene interactions except for the digenic ratios, which may indicate a more complex interaction.