Use of morpho-physiological and biochemical traits to identify sources of drought and heat tolerance in chickpea (Cicer arietinum)

Productivity of chickpea (Cicer arietinum) under current climatic conditions is severely limited by water deficit and high temperatures, either alone or in combination. Breeding for improved tolerance, and increasing understanding of the physiological and biochemical mechanisms underlying tolerance, are imperative for achieving yield stabilisation. We evaluated 36 chickpea genotypes including 21 interspecific derivatives (from the cross C. arietinum ICCV96030 × C. pinnatifidum IC525200), their parents, 10 elite genotypes, and three checks (drought tolerant, heat tolerant, drought and heat susceptible) under three environments: timely sowing with irrigation, timely sowing with drought stress, and late sowing leading to heat stress. Four parameters were considered: seed yield, proline content, membrane permeability index, and relative leaf water content. Although the average seed yield plummeted under both stresses, the impact of high temperature was more pronounced. Mean leaf water content declined, whereas membrane permeability index and proline content increased, under both stresses. Leaf water content showed a significant positive correlation with seed yield under all environments, and thus can be employed as an early-stage screening strategy in breeding programs for developing stress tolerant genotypes. Based on estimated stress susceptibility indices for seed yield, derivative line GLW605 was identified as a promising donor for both drought and heat tolerance. Additionally, three derivative lines (GLW607, GLW649, GLW677) were found tolerant to drought, and one derivative line (GLW669) showed tolerance to heat alone. Yield levels of the identified lines were statistically on par with respective tolerant checks. Results suggest that tolerance to drought and heat was successfully introgressed from the wild species, C. pinnatifidum, into the cultivated background. The promising derivative lines can be employed for developing multi-stress tolerant cultivars.