Application of Trichoderma harzianum enhances salt tolerance and yield of Indian mustard through increasing antioxidant enzyme activity

Growth and yield reduction of crops due to salt stress have become a serious issue worldwide. <i>Trichoderma</i> is very well known as a plant growth-promoting fungi under abiotic stress conditions. Therefore, this study was designed to investigate the effect of <i>Trichoderma harzianum</i> on the growth, yield, nutrient uptake, and antioxidant activity of three Indian mustard genotypes under saline condition (EC 9.28 dS m^-1). A two-factorial (<i>Trichoderma</i> and Indian mustard genotypes) pot experiment was conducted following a completely randomized design (CRD) with four replicates. <i>Trichoderma</i> was applied to soil as compost and suspension. The BD-7104 genotype showed better performance than Tori-7 under saline conditions. Compared to control, application of <i>T. harzianum</i> showed better performance in enhancing growth and yield of all the genotypes by increasing plants' tolerance to salt stress. Again, <i>Trichoderma</i> application increased the chlorophyll, proline, and oil content of Indian mustard. The generation of antioxidant enzymes viz., SOD, CAT, APX, and POD was significantly increased and, synthesis of H₂O₂ and MDA was decreased to a variable degree under different <i>Trichoderma</i> treatments. On average, application of <i>Trichoderma</i> as compost enhanced seed yield by 23 % than control. The better growth and yield in <i>Trichoderma</i> treated plants were the results of better uptake and assimilation of N, P, S, Ca, Mg, and K and reduced uptake of Na with a lower Na/K. Overall, BD-7104 genotype can be grown in soil treated with <i>Trichoderma</i> as compost at a rate of TdC_12.5 for obtaining better yield and nutritional quality under salinity stress condition.