SELEÇÃO ASSISTIDA POR MARCADORES DE DNA EM RETROCRUZAMENTO VISANDO RESISTÊNCIA AO MOFO BRANCO EM FEIJOEIRO

Abstract

The present study aimed to use DNA markers to select plants for the first and second backcross (BC) of two distinct populations of common bean, carrying the QTL for resistance to white mold and RAPD and microsatellite markers to identify the plants of the BC population more similar to their recurrent parent. For this, it was used the lines G122 (resistant - P1) as donor parent and VC3 (susceptible - P2) as recurrent parent for generation of the population F1RC1-GV evaluated for resistance to white mold by means of the SCAR Phs and genotyped with RAPD primers. In the F1RC2-EM population were used the lines Ex Rico 23 (resistant) as donor parent and M20 (susceptible) as recurrent parent evaluated for resistance to white mold, by means of RAPD primers O12.1600 and O15.1800 and genotyped with microsatellite (SSR) primers. Genetic similarity (sgij) between each BC plant and the recurrent parent was estimated using the Sorensen-Dice coefficient. The proportion of the SSR alleles derived from the recurrent parent was also estimated and, simultaneously, genetic similarity and the proportion of SSR alleles were efficient for identifying plants more similar to the recurrent parent. It was found that marker assisted selection (MAS) contributes to reducing the number of BC in at least a generation.