GENETICS OF QUANTITATIVE RESISTANCE TO YELLOW RUST (Puccinia striiformis f. sp. hordei) IN THREE BARLEY CULTIVARS

Abstract

There is very little information on the quantitative resistance of barley to yellow rust (Puccinia striiformis f. sp. hordei). Therefore, it is important to generate information about the genetics of resistance to assist breeding programs. In this study three cultivars (Calicuchima-92, Gloria/Copal and Alelí) having quantitative resistance to barley yellow rust, which were generated by International Center for Agricultural Research in Dry Areas and Centro Internacional de Mejoramiento de Maíz y Trigo, were crossed with Apizaco, a highly susceptible cultivar. The responses of F₁, F₂ and F₃ generations were assessed after inoculation with a variant of race 24 of Puccinia striiformis f. sp. hordei. The F₁ generation showed partial recessiveness in all crosses. F₂ and F₃ generations showed segregation for two loci in Calicuchima-92 and Gloria/Copal cultivars and for three loci in Alelí. A common locus was found in each cross of resistant by resistant cultivars, suggesting that in these three populations exist four to five genes that may be accumulated by hybridization and selection techniques.