Novas evidências experimentais da resistência genética na cultivar de feijoeiro comum México 222 e validação do marcador molecular SW12

Abstract

The aim of this study was to determine the inheritance of resistance to anthracnose using the cross between the cultivars Mexico 222 (R) × Michigan Dark Red Kidney (S) inoculated with race 7, and to investigate the independence of the genes of Mexico 222 from those previously characterized Co-1, Co-2, Co-3, Co-4, Co-5, Co-6 and Co-7 genes. The inheritance tests performed on the F2 population from Mexico MDRK × 222 cross, inoculated with race 7, revealed the existence of two dominant genes for resistance in the cultivar Mexico 222. Additionally, tests for allelism in F2 populations from Mexico 222 × Cornell 49-242 and Mexico 222 × AB 136 crosses, inoculated with race 7, also revealed the presence of two genes in Mexico 222. The absence of segregation was observed in 100 F2 individuals from each population derived from Mexico 222 × G 2333 and Mexico 222 × H1 line crosses, inoculated with race 7, revealing the presence of allelism. However, the nature of resistance Mexico 222 to race 23 of C. lindemuthianum is monogenic. The results showed that the genes of Mexico 222, G 2333 and H1 line, actually are alleles of the same locus that confers resistance to race 7 C. lindemuthianum. The molecular marker SW12 tested in the F2 population from the Mexico 222 × Widusa cross revealed that this marker is linked to Co-3 gene, in coupling phase, at a distance of 5.8 cM.