Identification and Mapping of QTLs for Resistance to Ascochyta Blight (Pathotype III) in Chickpea

Abstract

Microsatellites have become markers of choice for molecular mapping and marker assisted selection of key traits such as disease resistance in many crop species. The aim of this study was to construct a genetic linkage map and analysis of quantitative trait loci (QTLs) for Ascochyta blight resistance in chickpea (Cicer arietinum L.), as well as quantify the contribution of each QTL to observed phenotypic variation. Fifty-eight SSR markers and one morphological marker (flower color) were mapped on F2 individuals and F2:3 families derived from the cross ICC 12004 (resistant) × Bivanij (susceptible local variety) at the International Center for Agricultural Research at Dry Area (ICARDA). The linkage map comprised eight linkage groups, excluding flower color which didn't assign to any linkage group. Area under disease progress curve (AUDPC) was used to evaluate the F2 population and F3 families. Using composite interval mapping, three genomic regions were detected, which were in association with reaction to Ascochyta blight. These QTLs on LG3, LG4 and LG6 accounted for 46.5% of the total estimated phenotypic variation for reaction to Ascochyta blight. Fine mapping of the QTLs identified in this study would lead to the identification of markers that could be used for marker-assisted selection of chickpea genotypes with resistance to Ascochyta blight. These findings are particular pertinent considering that we used Ascochyta rabiei pathotype III and ICC 12004 (resistant to pathotype III) for the first time.