Inheritance of reaction to Puccinia hordei in barley. 1. Genes for resistance among North American race differentiating varieties

Abstract

The North American barley leaf rust differential varieties were studied to determine the number of loci fog genes conditioning reaction to culture 57-19 of Puccinia hordei race 4. Each of the 9 differential varieties was crossed with Moore, as susceptible variety, to determine the number of genes for resistance in each; and all 9 were crossed with each other to determine wheter any had genes for resitance at common loci. Four gene loci were identified and tentatively designated A, B, C, and D. The possible existence of a fifth locus was recognized and this was designated X. Locus A occurs in Reka 1,Bolivia and Quinn; B occurs in Quinn; C occurs in Gold and Lechtaler; X is the locus of the second gene in Bolivia and is os designated because it has not been distingu8shed fromthe B locus of Qinn. No genes for resistance were found in Egypt 4.