Adaptação da técnica de fluorescência para fins de genotipagem com novos marcadores microssatélite em feijoeiro

The objectives of this work were to adapt the fluorescent labeling (PCR) technique using M13 universal primer for genotyping purposes, and to present a new set of microsatellite markers for common bean (Phaseolus vulgaris L.). A large population (380 common bean lines) was used for microsatellite genotyping. PCR fluorescent labeling method showed to be very efficient for multiplex analysis, providing lower costs and saving time, thus increasing the quality of genotyping analysis. A new set of 50 microsatellites developed from an enriched library derived from cultivar IAC-UNA was presented. This study provides better tools for assisting common bean breeding programs.Os objetivos deste trabalho foram adaptar a técnica de marcação fluorescente de produtos da (PCR) com uso do iniciador universal M13, para aplicação em genotipagem, e apresentar novos marcadores microssatélite para o feijoeiro (Phaseolus vulgaris L.). Uma população de grande tamanho amostral (380 linhagens) foi utilizada para genotipagem dos microssatélites. O método de PCR marcado por fluorescência demonstrou ser muito eficiente para a análise "multiplex" e proporcionou a redução de custos e ganho de tempo, aumentando a qualidade de análise da genotipagem. Foram apresentados 50 novos locos de microssatélites, desenvolvidos a partir de biblioteca enriquecida a partir da cultivar IAC-UNA. Este estudo fornece ferramentas melhores para assistir aos programas de melhoramento do feijoeiro

Linkage and mapping of quantitative trait loci associated with angular leaf spot and powdery mildew resistance in common beans

Angular leaf spot (ALS) and powdery mildew (PWM) are two important fungi diseases causing significant yield losses in common beans. In this study, a new genetic linkage map was constructed using single sequence repeats (SSRs) and single nucleotide polymorphisms (SNPs), in a segregating population derived from the AND 277 x SEA 5 cross, with 105 recombinant inbred lines. Phenotypic evaluations were performed in the greenhouse to identify quantitative trait loci (QTLs) associated with resistance by means of the composite interval mapping analysis. Four QTLs were identified for ALS resistance. The QTL ALS11AS, linked on the SNP BAR 5054, mapped on chromosome Pv11, showed the greatest effect (R2 = 26.5%) on ALS phenotypic variance. For PWM resistance, two QTLs were detected, PWM2AS and PWM11AS, on Pv2 and Pv11, explaining 7% and 66% of the phenotypic variation, respectively. Both QTLs on Pv11 were mapped on the same genomic region, suggesting that it is a pleiotropic region. The present study resulted in the identification of new markers closely linked to ALS and PWM QTLs, which can be used for marker-assisted selection, fine mapping and positional cloning