Genetic Analysis and Molecular Mapping of Quantitative Trait Loci in Common Bean Against Pythium ultimum

Campa A Perez Vega E Pascual, A and Ferreira J J 2010 Genetic analysis and molecular mapping of quantitative trait loci in common bean against Pythium ultimum Phytopathology 100 1315 1320 Pythium ultimum is a soil pathogen that can cause seed decay and damage to roots in common bean In this study the response of a set of 40 common bean genotypes to P ultimum and inheritance of the resistance in the 92 F-7 recombinant inbred lines (RIL) developed from a cross between Xana and Cornell 49242 was investigated by using emergence rate and seedling vigor Emergence of the 40 genotypes showed a significant association between white seed coat and response to this pathogen Among these 11 common bean genotypes all with colored seeds ex hibited a high percentage of emergence and seedling vigor not significantly different (P > 0 05) to noninoculated plants Response of the RIL population revealed both qualitative and quantitative modes of inheritance A major gene (Py 1) controlling the emergence rate was mapped in the region of the gene P a basic color gene involved in control of seed coat color located on LG 7 Using the RIL subpopulation with colored seeds a significant quantitative trait loci (QTL) associated with the emergence rate (ER3(xc)) and another with seedling vigor (SV6(xc)) were identified on the LG 3 and 6 respectively QTL SV6(xc) was mapped in the region of the gene V another gene involved the genetic control of color QTLs associated with seed traits were mapped in the same relative position as regions involved in responses to P ultimum suggesting the possible implication of avoidance mechanisms in the response to this pathogen