Association Mapping For Abiotic Stress Tolerance In Chickpea

Abiotic stresses like drought and heat are major constraints to chickpea production in arid and semi-arid regions of the world. To understand the genetic basis of these complex traits association mapping approach was employed in the present study. Phenotypic data generated on reference set (300 genotypes, which include 211 mini-core collections) for drought tolerance related root traits, heat tolerance, yield and yield component traits and drought tolerance phenotyping data in 1-7 seasons and 1-3 locations in India and Africa was assembled. DArT markers equally distributed across chickpea genome were used to determine population structure, as a result three sub-populations were identified using admixture model in STRUCTURE. Genome-wide and candidate gene-based association studies were conducted using 1,872 markers (1,072 DArTs, 651 SNPs, 113 gene-based SNPs and 36 SSRs) and phenotyping data generated employing mixed linear model (MLM) analysis with compression method and kinship matrix. As a result, 583 significant marker-traits associations (MTAs) were identified and maximum number of MTAs was identified for 100-seed weight (113) and the loci identified through association studies explained ~38.5% phenotypic variation. Among 113 gene-based SNP markers 6 SNPs in ASR, 3 SNPs each in dehydrin and DREB were found to have significant associations with different traits like 100-seed weight, Δ carbon, plant height, root dry weight, pods per plant and yield. This study provides significant marker trait associations that can be used for enhancing drought and heat tolerance through molecular breeding.