Genetic and Molecular Studies on Heat Tolerance in Chickpea [Cicer Arietinum (L.)]
- M.Sc. (Agri)
- Dharwad University of Agricultural Sciences 2024
- 141 32 Cms
ABSTRACT
Forty chickpea genotypes were evaluated under two growing conditions, timely sown (TS) and late sown (LS) conditions during Rabi 2023-24, at College of Agriculture, Vijayapur, with aim of screening for heat tolerance (HT). The LS condition mimicking the heat stress was taken up as to coincide the reproductive stage with high temperature. Genetic diversity analysis using D2 statistic identified 12 clusters under TS and 6 under LS. The number of primary branches contributed most to diversity under TS (15.6%), while days to maturity (DM) contributed the maximum under LS (15.3%). Significant positive correlations of yield was observed with pollen viability, number of pods per plant, plant biomass, canopy temperature depression and total chlorophyll content in both the conditions. Conversely, significant negative correlations were found with days to fifty per cent flowering and DM under LS condition. Heat tolerance indices, like heat and productivity index (HPI), mean productivity (MP), per cent reduction of yield (PRY) and heat susceptibility index (HSI) were computed to identify superior HT genotypes. Based on HSI, genotypes were categorized into four groups as highly HT (2), HT (7), moderately HT(11) and heat susceptible (20). Genotypes, ICC 4958, DIBG 205, M 71, ICCV 191216 and BGD 111-1 were identified as superior, displaying high HPI and MP with low HSI and PRY. Molecular diversity was assessed using 15 SSR markers, all of which were polymorphic with an average of 9.2 alleles per marker with mean PIC of 0.7843. Marker TA64, exhibited the highest number of alleles (15) with PIC of 0.8264. UPGMA clustering grouped the genotypes into 6 clusters, with the HT check JG 14 and highly heat tolerant line ADL 72 in the same cluster. The identified heat tolerant genotypes will further be evaluated in advanced yield evaluation trials towards identifying the climate resilient cultivars.