Drought Resilience of Wheat Genotypes Through Microbial Biostimulants Under Water Deficit Regimes

Drought resilience strategies are needed to tackle the escalating issue of water scarcity and to sustain crop productivity under water deficit conditions. There is a gap in identifying the most effective consortium of microbial biostimulants and understanding the underlying physiological and antioxidant mechanisms involved in the drought resilience of wheat (Triticum aestivum L.) crop. To address this, three experiments were carried out in laboratory and wire house conditions to identify and optimise the response of drought-tolerant microbial biostimulants for wheat genotypes. Three drought-tolerant microbial biostimulants: Bacillus subtilis, Bacillus megaterium and Trichoderma harzianum were selected from a laboratory study. The two wheat genotypes: Dilkash-2021 and Bakhar Star (drought tolerant and sensitive, respectively) were selected from a wire house experiment. Afterwards, the response of individual and consortium of selected drought-tolerant microbial biostimulants was evaluated in drought-tolerant and sensitive wheat genotypes under well-watered and water deficit regimes. Results indicated that seed inoculation of drought-tolerant genotype with the microbial consortium of Bacillus subtilis, Bacillus megaterium and Trichoderma harzianum significantly increased relative water contents (58%), stomatal conductance (39%), sub-stomatal conductance (70%), water use efficiency (38%) and net leaf photosynthetic rate (34%) as compared with the un-inoculated control under water deficit. Furthermore, a significant reduction in malondialdehyde concentration (36%) and an improvement in proline contents (77%), superoxide dismutase (82%) and peroxidase (51%) were observed with this microbial consortium under water deficit. Therefore, seed inoculation of drought-tolerant wheat genotypes with the microbial consortium might be considered in formulating the best agricultural practices for alleviating the adverse effects of water deficit on the wheat crop.