Genome-wide association analysis using multi model approach identified novel associations for plant architectural traits in chickpea germplasm collection

Abstract

Crop plant architecture dictates plant performance under different ecological conditions and is responsible for its establishment, development, and morphology. It plays an important role in plant breeding for yield optimization, regulating photosynthetic rate and efficiency, utilization of resources, occurrence of pests and diseases, effective mechanical harvesting, space optimization, and improving the quality of plant produce. The subtle changes in the plant’s architecture could help the plant adapt to different ecological niches and are very important, keeping in view the challenges posed due to climate change. A set of 280 diverse genotypes, which included the core collection of chickpea was evaluated during the rabi season of 2021 and 2022. A total of 10 plant architecture related traits, including plant height, first pod height, canopy width, inter-nodal length, and days to flowering were studied and significant variability was observed as per the analysis of variance (ANOVA) and phenotypic descriptors. Diversity based on π and θ estimates suggests the presence of substantial diversity, while Tajima’s D reflects balancing selection due to the abundance of shared alleles. Significant marker trait associations (MTAs) for traits like plant height (PH), first pod height (FDPH) and days to flowering were observed using trait based or BLUP estimates. In total, 97 and 51 MTAs were identified using trait based and BLUP based on multi model GWAS analysis, respectively. Among these 17 were consistent MTAs being present either across the year or were identified using more than one GWAS model. Likewise, 9 consistent MTAs were identified using the BLUP estimates. Interestingly, two genomic regions present on chromosome 5 and 7 were found to harbor multiple MTAs for PH and FPDH. The linkage disequilibrium (LD) block analysis reflects the prevalence of multiple LD blocks in these regions. The allelic effects of the MTAs reflect their additive nature in determining the phenotype. Overall, the MTAs identified in the current study are highly useful for the chickpea breeder in modulating the plant architecture, mainly PH and FPDH.