Characterization of stress-induced changes in morphological, physiological and biochemical properties of Indian bread wheat (Triticum aestivum L.) under deficit irrigation

Abiotic stresses in wheat, particularly drought (DR), hamper wheat production and causes up to 86% yield losses. Therefore, developing stress-tolerant genotypes is a major challenge in wheat breeding. In this study, we evaluated 72 diverse wheat genotypes for DR tolerance over two consecutive years, examining 12 morpho-physiological traits under irrigated (IR) and DR conditions. Under DR, grain yield (GY) was significantly associated with biomass and phenological traits. The principal component analysis accounted for 82.79% and 80.08% of the overall variation during IR and DR stress conditions, respectively. Based on GY component traits and drought susceptible index, two tolerant (IC36761A and IC128335) and two susceptible (IC138852 and IC335732) genotypes were selected for physio-biochemical analysis. In these genotypes, the membrane stability index (MSI) ranged from 57 to 74% and 35 to 64% under IR and DR conditions. Genotype IC128335 showed 78.10% relative water content (RWC), 2.97 mg/g tannin, and 3.67 mg/g fresh weight reducing sugar (RS) content under DR conditions. Abscisic acid (ABA) content ranged from 0.81 to 4.03 ppm/g dry weight (DW) and 0.92-4.23 ppm/g DW under IR and DR stress conditions, respectively. There was a significant genotype x environment interaction observed for the physio-biochemical traits. The genotypes IC36761A and IC128335 suffered less reduction in MSI and RWC. RS and flavonoid content significantly increased in all four genotypes, but the tannin and ABA levels increased especially in IC128335 and IC36761A under DR conditions. The physio-biochemical findings support the DR tolerance of genotypes IC128335 and IC36761A, indicating their potential for inclusion in breeding programs aimed at enhancing DR tolerance in bread wheat.

Automated summary

Abiotic stresses, such as drought, have a significant impact on wheat production, causing up to 86% yield losses. This study evaluated the tolerance of 72 diverse wheat genotypes to drought stress and identified two tolerant genotypes (IC36761A and IC128335) with promising physio-biochemical traits. These genotypes exhibited higher membrane stability index, relative water content, and lower levels of tannin under drought conditions. The findings suggest that IC36761A and IC128335 have the potential to be included in breeding programs aimed at enhancing drought tolerance in bread wheat.