Identification of a Stable Drought-Tolerant High-Yielding Line for Chickpea Crop Improvement

Chickpea (Cicer arietinum L.) is grown in marginal land with low input and is, therefore, drought-prone. In order to develop a drought-tolerant line, a bi-parental recombinant inbred line (RIL) mapping population was generated by inter-crossing between two varieties JGK3 (ICCV 95334) and Himchana1 (ICCX-810800) having contrasting root traits. Ninety-two genetically diverse RILs of F₈ generation were selected based on their total root length to root dry weight ratio (RL/DW). The leaf relative water content of these RILs under low soil moisture did not show any strong correlation with the RL/DW. Twenty RILs having high RL/DW were evaluated for seed yield in a field under rainfed condition without any supplementary irrigation. The best performing RIL, which performed better than the check varieties, was reevaluated for a further year under rainfed condition. The genotypic constitution of this superior low soil moisture tolerant individual RIL was determined by constructing its recombination map using genome-wide SNPs obtained through genotyping-by-sequencing. The RIL possesses the superior alleles of the genomic QTL region known to govern drought tolerance in chickpea. The phenotypic and genotypic characterization of RILs in our study identified a chickpea pre-breeding line that can be used as a genetic donor for developing drought-tolerant high-yielding chickpea varieties and our results provide an evidence that total root length to root dry weight ratio can be used as a quantitative trait for assessing drought tolerance.