Identification of QTLs associated with root architectural pattern during domestication of common bean (Phaseolus vulgaris L.)

Abstract

Domestication of crop plants involves the selection for the most desirable phenotypes, and results in the alteration of allele frequencies of certain target loci. Previous analyses of domestication have mainly focused on above-ground plant organs, while root traits have been largely neglected mainly due to the visual inaccessibility of this organ. However, it is very likely that some domestication-associated changes in root growth and architecture might have happened as a consequence of selection for above-ground plant parts as these organs operate in functional equilibrium with each other. Thus, we hypothesized that domestication of the common bean brought about changes in root traits controlled by two types of genes, one that controls root growth only, while the other regulates the functional balance between root and shoot. We have performed a QTL analysis using a recombinant inbred population derived from a cross between a landrace (G19833) and a wild accession (G23419), both from the Andean gene pool. A SNP-based linkage map was constructed using the genotyping-by-sequencing (GBS) approach. Time series root images were collected using a novel 2-dimensional phenotyping platform. Phenotypic and genotyping information was used to identify various root and shoot related QTLs. Like previous domestication studies, QTLs for different traits were clustered on various genomic regions