Ascochyta Blight of Chickpea ( <scp> <i>Cicer arietinum</i> </scp> L.): Genetic Basis of Resistance and QTL Mapping

ABSTRACT Chickpea ( Cicer arietinum L.) production is adversely affected by Ascochyta blight (AB), a disease caused by the highly variable pathogen Ascochyta rabiei . In order to enhance genetic resistance, the study was undertaken to investigate the inheritance pattern(s) and identification of associated quantitative trait loci (QTLs). Inheritance studies in F 2 and F 2:3 populations of HC5 × IC117744 cross revealed the prevalence of digenic‐inhibitory gene interaction. The HC5 parent contributed the allele suppressing the resistance. The reciprocal cross ruled out the presence of maternal or cytoplasmic inheritance. Non‐pallelic relationship among AB resistant accessions (IC117744, IC248147 and IC275447) indicated the interplay of complex intergenic interactions. Parental polymorphism survey of 481 SSR markers identified 52 polymorphic markers between HC5 and IC117744. Bulked Segregant Analysis (BSA) revealed six markers linked to resistance against AB. QTL mapping with IciMapping 4.2 software identified two major QTLs, qtl4.1 and qtl4.2 , on linkage group (LG) 4. These QTLs were positioned 9.2 cM distal to the SSR marker TA130 and 9.48 cM distal to CaM2049, highlighting a key genomic hotspot associated with AB resistance. The linked SSR markers offer valuable tools for marker‐assisted selection (MAS). Further, fine mapping and functional characterization of these regions will facilitate the development of durable disease‐resistant chickpea cultivars.