Investigation of physiological and biochemical reactions of dryland wheat cultivars to cold stress in conservation agricultural system

Conservation agriculture is one of the successful strategies of sustainable agriculture in the context of climate change. Conservation agriculture with residues mantanance systems, could decrese soil temperature and this may affect crop growth in cold regions. For this purpose, an experiment was conducted during 2018-2019 and 2019-2020 in two controlled and field conditions in Dryland Agricultural Research Institute of Maragheh. Under controlled conditions, wheat genotypes (Baran, Saradri, Rizhav, Saji, Rascon, Gerdish) were exposed to different cold and frost temperatures (+4, -5, -10 and -15 ° C) and under field conditions, those genotypes were planted inthree different dates (late shahrivar, late mehr and late aban) in chickpea rotation under conservation tillage (no till) and conventional tillage conditions. Results of controlled conditions showed that Sardari and Baran cultivars are cold tolerant cultivars due to having the highest amount of chlorophyll and Superoxide dismutase (SOD) and the lowest content of malondialdehyde (MDA). In contrast, H2O2 content in Rizhav and Saji genotypes at -15 ° C was higher than other genotypes. In conservation tillage conditions, all of the genotypes had the highest antioxidant enzymes activity and the lowest content of H2O2 and MDA. However, Sardari and Baran were more effective genotypes under cold stress conditions, compared toother genotypes. According to the results, in cold drylands regions, planting date can affect phenological stages of the plants in dealing with cold stress in winter and spring, and selection of cold-tolerant genotypes can improve physiological characteristics of plants especially in conservation agriculture system under cold stress conditions.