QTL mapping of early flowering and resistance to ascochyta blight in chickpea

In western Canada, chickpea (Cicer arietinum L.) production is challenged by short growing seasons and infestations with ascochyta blight. Research was conducted to determine the genetic basis of the association between flowering time and reaction to ascochyta blight in chickpea. Ninety-two chickpea recombinant inbred lines (RILs) developed from a cross between ICCV 96029 and CDC Frontier were evaluated for flowering responses and ascochyta blight reactions in growth chambers and fields at multiple locations and during several years. A wide range of variation was exhibited by the RILs for days to flower, days to maturity, node of first flowering, plant height, and ascochyta blight resistance. Moderate to high broad sense heritability was estimated for ascochyta blight reaction (H(2) = 0.14-0.34) and for days to flowering (H(2) = 0.45-0.87) depending on the environments. Negative correlations were observed among the RILs for days to flowering and ascochyta blight resistance, ranging from r = -0.21 (P < 0.05) to -0.58 (P < 0.0001). A genetic linkage map consisting of eight linkage groups was developed using 349 SNP markers. Seven QTLs for days to flowering were identified that individually explained 9%-44% of the phenotypic variation. Eight QTLs were identified for ascochyta blight resistance that explained phenotypic variation ranging from 10% to 19%. Clusters of QTLs for days to flowering and ascochyta blight resistances were found on chromosome 3 at the interval of 8.6-23.11 cM and on chromosome 8 at the interval of 53.88-62.33 cM.