Assessment of Drought Tolerance in Coriander (Coriandrum sativum L.) through Physiological Indices

The present investigation aimed to assess the impact of moisture stress on physiological traits in coriander genotypes to identify drought-tolerant lines that can be exploited for improving yield under water-limited conditions. A two-year study (rabi 2021–22 and 2022–23) was conducted at the University of Agricultural Sciences, Dharwad, to evaluate twenty coriander (Coriandrum sativum L.) genotypes for drought tolerance based on physio-biochemical indices. The experiment was carried out under a strip-plot design at two soil moisture regimes: well-irrigated and drought-induced. The physio-chemical parameters such as relative leaf water content, chlorophyll content, chlorophyll stability index, membrane stability index and proline content were analysed at 60 DAS. Total chlorophyll in leaves and the Chlorophyll stability index were determined by the DMSO (dimethyl sulphoxide) method. Proline content was determined by using the acid ninhydrin reagent. Drought stress caused a significant decline in relative water content, total chlorophyll content, chlorophyll stability index, and membrane stability index, whereas leaf proline accumulation increased markedly. Genotypes RCr-446, RCr-41, RCr-435, and RCr-728 demonstrated superior performance, exhibiting higher RWC, chlorophyll content, CSI, MSI and elevated proline levels under both stress and non-stress conditions alongside the lowest stress susceptibility index, indicating their potential for drought tolerance. This study may help understand some adaptive mechanisms developed by coriander cultivars and contribute to identifying useful traits for coriander breeding programmes.