Effect of seed priming and application of cytokinin and auxin on growth and grain yield of wheat (Triticum aestivum L.) under Ahvaz climatic conditions

In order to evaluate the effect of seed priming and application of cytokinin and auxin on grain yield of wheat cv. Chamran, an experiment was carried out in Agriculture Faculty of Shahid Chamran University of Ahvaz, Iran, during 2015-2016 and 2016-2017 growing seasons. Experiment was carried out in a factorial arrangement based on randomized complete block design with three replications. Treatments included seed priming (hydropriming and control) and plant growth regulators application (nine cytokinin and auxin application levels at 1 and 2 weeks after anthesis). Results showed that hydropriming treatment significantly increased grain yield about 8% compared to control (7030 and 6507 kg.ha-1, respectively). Application of cytokinin and auxin had positive effects on photosynthesis and soluble proteins content of flag leaf. In addition number of endosperm cells was increased in these treatments. The highest effect on increasing source strength was observed in application of cytokinin in both times of foliar application. Grain filling rate was significantly higher (1.79 mg.day-1) in cytokinin-cytokinin foliar application. Grain yield in foliar application of cytokinin-cytokinin (7891 kg.ha-1) was 24.7% higher, compared to control (application of water in both times). Interaction of seed priming and plant growth regulators application was not significant for any evaluated traits. Results of this experiment showed that seed priming caused increase in number of spike.m-2. Foliar application of auxin and cytokinin also may increase grain yield of wheat by enhancement of physiological source and sink strength.