Submitted to: Crop Science
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/15/2013
Publication Date: 3/21/2014
Citation: Mukeshimana, G., Butare, L., Cregan, P.B., Blair, M.W., Kelly, J.D. 2014. Identification of quantitative trait loci associated with drought tolerance in common bean using SNP markers. Crop Science. 54:30-45. Interpretive Summary: The common bean is an extremely important food source worldwide and drought stress is a major limiting factor in common bean production. It was the objective of this study to determine the positions of genes or quantitative trait loci (QTL) that are associated with traits related to common bean drought tolerance. Progeny were developed from the cross of the drought resistant common bean variety SEA5 and CAL96 which is a line with limited drought tolerance. The parental lines and the progeny population were grown for three years in and Rwanda and one year in Columbia in experiments that included both drought stress and non-stress conditions. A number of traits were measured including days to flower, to maturity, and to seed fill; the ratio of seed weight to total plant weight, pods per plant, seeds per pod, 100-seed weight, seed yield and seed yield per day. The parents and progeny were also analyzed with single nucleotide polymorphism (SNP) DNA markers and a genetic map of the population was created. A total of 14 genes/QTL for performance under drought stress were consistently identified in the four different environments. These genes/QTL and the genetic markers associated with them can be used by common bean breeders to select common bean breeding lines that carry the genes/QTL that are associated with drought stress.
Technical Abstract: Drought stress is the major limitation of common bean (Phaseolus vulgaris L.) grown in subsistence farming systems worldwide. The objective of this study was to use single nucleotide polymorphism (SNP) markers from the BARCBean6K_3 BeadChip to identify quantitative trait loci (QTL) associated with traits related to drought tolerance in common bean. An inter-genepool recombinant inbred line (RIL) population from a cross of drought tolerant line SEA5 and CAL96 cultivar was evaluated in Rwanda for three years and in Colombia for one year under drought stress (DS) and non-stress (NS) conditions. Traits evaluated included the phenology traits numbers of days to flower, to maturity, and to seed fill; harvest index and pod harvest index; yield and yield components including number of pods per plant, seeds per pod, 100-seed weight, and seed yield per day. Harvest indices, and seed weight were stable regardless of water treatment while number of pods per plant, seeds per pod, and yield were significantly reduced by drought stress. A linkage map of the RIL population spanning 1,351cM was constructed using 2,122 SNP markers. The map covered all eleven bean chromosomes with an average distance of 0.64 cM between markers. A total of 14 QTL for performance under drought were consistently identified in different environments. QTL associated with phenology and seed weight traits mapped near previously reported QTL. Linkage between seed weight and yield QTL SY3.3SC was observed on Pv03 and could be used to simultaneously select for seed yield and size in inter-genepool crosses of common bean.