Responses of germination, early growth and phenology of barley to salicylic acid under salinity stress conditions

In this research, the effect of concentration and time of seed priming with salicylic acid on germination and early growth and it’s application methods under salinity stress conditions on phenology characteristics of barley, variety Reyhan, was studied in two separate experiments. The effect of concentration (in five levels, control, 0.5, 0.75, 1.0 and 1.5 mM) and time (in three levels, 6, 12 and 24 h) of seed priming by salicylic acid (SA) in the first experiment and different application methods of SA (no application, priming and spraying at the stages of establishment, double ridges and anthesis) under different salinity conditions (no stress and salinity of 6 and 12 dS.m-1)in the second experiment was evaluated. Both experiments were conducted as completely randomized design with four replications at College of Agriculture, Shiraz University, Iran, in 2014. The results of the first experiment showed that SA-priming with 1.5 mM for 12 h had the highest positive effect on germination and early growth, which was selected for the second experiment. The results of the second experiment showed that salinity stress of 6 dS.m-1 reduced the planting to anthesis period as well as planting to physiological ripening and 12 dS.m-1salinity stress also reduced the planting to booting, planting to anthesis and planting to physiological ripeningperiods. Seed priming with SA prolonged the growth periods, whereas the delay in SA application decreased its positive effect. Foliar application at establishment increased planting to booting, planting to anthesis as well as planting to physiological ripening periods,however foliar application at anthesis had no significant effect on phenology of barley plants. In total, seed priming or foliar application at establishment at early growth stages ameliorated the acceleration of the developmental stages due to salinity stress and early application of SA was found to be more important with increasing salinity stress.