Investigation of antioxidant enzymes activity under drought stress conditions in some bread wheat advanced genotypes

Wheat is one of the main cereals in cultivated areas and production rate worldwide. This product is the primary source of carbohydrates and protein in the human diet, and almost half of Iran's agricultural land is under wheat cultivation. On the other hand, drought stress stimulates a wide range of plant responses, from physiological and biochemical to molecular, and causes oxidative damage in plants. Plants use antioxidant enzymes to deal with these stresses. Regarding the role and importance of antioxidant enzymes, the activity of these enzymes in irrigation and drought conditions was investigated in some wheat genotypes. In this research, the activity of peroxidase, catalase, superoxide dismutase enzymes and grain yield for 20 advanced bread wheat genotypes under drought stress conditions was carried out. The experiment was laid out in a randomized complete block design with three replications in two conditions, irrigated and rainfed conditions. The present research was carried out in the Research Field of the Department of Plant Production and Genetics, Campus of Agriculture and Natural Resources, Razi university. Based on the simple analysis of variance, genotypes showed significant differences in the activity of all three enzymes, peroxidase, catalase, and superoxide dismutase. The effect of environment, genotype, and the interaction effect of environment × genotype were significant for catalase, peroxidase, and superoxide dismutase enzyme activity, where the data were analyzed in the form of combined analysis. In irrigation conditions, the highest activity of peroxidase enzyme was observed in Genotype 12, catalase in Genotype 10 and superoxide dismutase in Genotype 15. In this condition, the lowest activity of peroxidase enzyme was observed in Genotype 11, catalase in Genotype 11 and superoxide dismutase in Genotype 7. Also, in dryland conditions, the highest level of peroxidase enzyme activity was observed in Genotypes 6, catalase in Genotype 2 and superoxide dismutase in Genotype 15, and the lowest level of peroxidase enzyme activity was observed in Genotypes 4, catalase in Genotype 8 and superoxide dismutase in Genotype 1. In terms of seed yield trait, the highest amount in irrigation conditions is related to Genotypes 10, 7, and 8, and the lowest amount is related to Genotypes 12, 13, and 11. In dryland conditions, the highest yield is related to Genotypes 4, 10, and 17, and the lowest level is related to Genotype 9. The results showed that the activity level of peroxidase, catalase, and superoxide dismutase enzymes is higher in drought environment than in irrigated conditions, and different genotypes show different responses to drought stress. In fact, the activity of antioxidant enzymes increased with drought stress. In fact, plants increase the activity of their antioxidant enzymes to deal with drought stress, eliminate oxygen free radicals, and deal with the oxidative stress that has occurred and affects the grain yield by spending energy. Based on this, knowing more about antioxidant factors and the factors affecting them, valuable solutions can be adopted to deal with drought stress in plants.