Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 7/1/1998
Publication Date: N/A
Interpretive Summary: Ascochyta blight is a fungal disease of chickpea that causes severe damage to the leaves, stems, pods and seeds. In many cases losses have been 100%. In this study we examined progenies from crosses of resistant and susceptible germplasm accessions and found that resistance is controlled by at least two recessive genes. Analysis of DNA markers that are associated with the resistance genes confirmed the inheritance of resistance and also provided a means of locating the genes in the chickpea genome. The associated DNA markers can be used for indirect selection for resistance in a breeding program. The use of the markers is expected to accelerate the breeding programs for resistance to the disease.
Technical Abstract: Ascochyta blight is one of the most devastating diseases of chickpea (Cicer arietinum L.) Worldwide and breeding for resistance is underway. To determine the inheritance of resistance and to locate the resistance genes, we used two populations of F5:6 recombinant inbred lines (RILs). One population was derived from an interspecific cross between C. arietinum and dC. reticulatum Lad., while the other population was derived from an intraspecific cross within C. arietinum. The RILs were scored for reaction to the pathogen and for numerous molecular markers. From the marker scoring data of interspecific cross, we constructed a partial linkage map of the Cicer genome that included 117 markers [1 morphological trait locus, 9 isozyme loci, 17 Inter Simple Sequence Repeat (ISSR) loci and 90 Random Amplified Polymorphic DNA (RAPD) loci] covering 877cM with an average distance of 7.5 cM between markers. We identified three quantitative trait tloci (QTL)(at LOD>3.0) that confer resistance to ascochyta blight. QTL-1, QTL-2 AND QTL-3 were mapped to linkage groups 6, 1 and 4, respectively. Two major loci, QTL-1 (LOD=13.4) and QTL-2 (LOD=5.0) accounted for about 35% and 15% of the total phenotypic variance among RIL'S respectively. The minor QTL (QTL-3, LOD=3.33) explained about 10% of the phenotypic variation. We identified two DNA markers that flank QTL-1 and single markers linked to QTL-2 and QTL-3. We infer that ascochyta blight resistance in this population is controlled by at least three QTL.