Antioxidant enzymes responses of some dryland wheat varieties to rotation and crop residues levels under conservation agricultural conditions

To study effects of crop residues and rotation levels on grain yield, chlorophyll content, activities of superoxide dismutase, Cu/Zn-SOD isozymes, Mn-SOD isozymes, Fe-SOD isozymes, glutathione reductase, ascorbate peroxidase, catalase, amount of hydrogen peroxide and malondialdehyde in five dryland wheat cultivars, Experimental treatments were: a) two wheat-wheat and forage-wheat rotations in the main plots, b) three levels of crop residues including non-use, 2 and 4 tons of residues in subplots, c) 5 wheat cultivars including Sadra, Hashtrood, Baran, Varan and Ohadi in sub-sub plots. Combined analysis of variance showed that the effects of rotation, crop residue values and cultivars were significant on most of the studied traits. The highest grain yield (1809.9 Kg/ha) was obtained from Varan cv. at 2 T/ha forage crop residue. The highest chlorophyll a, chlorophyll b and carotenoid were observed in 4 T/ha crop residues with forage-wheat rotation in Varan cultivar. Also, the lowest content of hydrogen peroxide and lipid peroxidation were recorded in 4 and 2 T/ha of crop residues in forage-wheat and Varan cultivars, respectively. Due to the importance of using conservation agricultural pattern in dry lands of Iran, in order to optimize the productivity of this model, in this study, maintaining plant residues of 2 tons per hectare with fodder-wheat rotation in rainfed conditions in Varan cultivars as the best treatment in terms of reduction the adverse effects of drought stress on the cell surface and maintaining the desired level of photosynthetic activity and thus the production of higher grain yield were known.