Resumo

MARISCAL AMARO, Luis Antonio et al. Test of similarity in genes with resistance to stem rust in oat genotypes. Rev. Mex. Cienc. Agríc [online]. 2010, vol.1, n.4, pp.541-554. ISSN 2007-0934.

The stem rust caused by Puccinia graminis Pers. f. sp. Avenae is considered the biotic factor that affects the most to oat cultivation (Avena sativa L.), decreasing yield and grain weight in susceptible varieties, in 75% and 60%, respectively. The strategy that has supported control of this disease is the use of resistant varieties, constantly requiring of resistance sources. The way resistance works, and the genes that give it to oat germoplasm, is still unknown; then is necessary to make more studies about number and similarity of genes as well as in their activity. The aim of the study was to determine similarity and number of resistance genes in mature plant and seedlings, in families F₃ of crosses between oat parents, moderately resistant to stem rust; due their importance for the programs of improvement as resistance sources, by means of analysis of the derived progenies of cross between them from 2006 to 2009. In greenhouse seedling state, the parents, considering each one apart, had readings of 0, ";", and 1, indicating their resistance to isolation PgaMex99.13. The families F₃ of all breeds didn't segregate susceptible families, indicating that these six parents have a gene in common conferring resistance against tested isolation. In field, even with inoculations of same isolation, the families in all breeds showed different infection levels, some above at 60% indicating the incidence of other breeds different to the one inoculated, for which the resistance gene common in the parents was not effective.

Palavras-chave : Avena sativa L.; Puccinia graminis Pers. f. sp. avenae Eriks. and Henn.; genetic diversity.

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