Mapping quantitative trait loci in chickpea associated with time to flowering and resistance to Didymella rabiei the causal agent of Ascochyta blight

Abstract

Drought is the major constraint to chickpea (Cicer arietinum L.) productivity worldwide. Utilizing early-flowering genotypes and advancing sowing from spring to autumn have been suggested as strategies for drought avoidance. However, Ascochyta blight (causal agent: Didymella rabiei (Kov.) v. Arx.) is a major limitation for chickpea winter cultivation. Most efforts to introgress resistance to the pathogen into Kabuli germplasm resulted in relatively late flowering germplasm. With the aim to explore the feasibility of combining earliness and resistance, RILs derived from a cross between a Kabuli cultivar and a Desi accession were evaluated under field conditions and genotyped with SSR markers. Three quantitative trait loci (QTLs) with significant effects on resistance were identified: two linked loci located on LG4 in epistatic interaction and a third locus on LG8. Two QTLs were detected for time to flowering: one in LG1 and another on LG2. When resistance and time to flowering were analyzed together, the significance of the resistance estimates obtained for the LG8 locus increased and the locus effect on days to flowering, previously undetected, was significantly different from zero. The identification of a locus linked both to resistance and time to flowering may account for the correlation observed between these traits in this and other breeding attempts.

Mapping of QTLs governing agronomic and yield traits in chickpea

“…plant height, plant spread, number of branches per plant, number of pods per plant, yield, seed weight and days to maturity (this study); seed number per plant, 100-seed weight, days to 50% flowering (Cho et al 2002); blight resistance (Tekeoglu et al 2002;Cho et al 2004;Lichtenzveig et al 2006); seed weight and lutein concentration (Abbo et al 2005) and seed size, yield and days to 50% flowering (Cobos et al 2007). Hence, concentrating on these LGs in molecular breeding programs might bring in simultaneous improvement in many of these traits.…”

An Update on Genetic Resistance of Chickpea to Ascochyta Blight

“…Further, this region also harbors the NAC domain protein for systemic acquired resistance as well as the NB-LRR-type disease resistance protein. In summary, QTLs contributing to A. rabiei (Ar) resistance were identified by many research groups-14 Ar loci located on eight chickpea LGs, named as Ar1a, Ar2a, Ar2b, Ar2c, Ar3a, Ar3b, Ar3c, Ar4a, Ar4b, Ar5a, Ar6a, Ar6b, Ar7a, and Ar8a [10,82,86,88,89,92,[95][96][97][98][99][100][101][102]. These markers will be important for enabling the pyramiding of resistance genes from diverse sources to reduce the time required to generate resistant cultivars.…”

Identification of candidate genes for dissecting complex branch number trait in chickpea

“…In order to ascertain the accuracy and novelty of seven genomic loci-carrying genes for branch number regulation in chickpea (identified by their validation in natural and mapping populations), the outcomes of the present study was compared/correlated with that of previous reports [18][19][20][21][22][23]. For this, markers linked/flanking the branch number known QTLs/genes (documented in previous QTL mapping studies), were selected for their further validation in the branch number-specific natural (60 diverse desi and kabuli Cicer accessions) and mapping populations [(ICC 4958 × ICC 17160) and (ICC 12299 × ICC 8261)] constituted in the present study.…”

“…The effect of branching on seed and pod yield as well as water-use efficiency is extensively studied and well documented in chickpea [17]. Only limited number of QTLs/genes regulating branch number have been identified utilizing QTL mapping and trait association analysis [18][19][20][21][22][23]. However, these identified QTLs/genes are yet to be deployed in marker-assisted selection for developing cultivars with high branch number in chickpea.…”