INFLUENCE OF THE TIMING OF THE APPLICATION OF SALICYLIC ACID ON THE QUANTITATIVE YIELD AND SOME BIOCHEMICAL CHARACTERISTICS OF BARLEY (Hordeum vulgare L.) UNDER DEFICIT IRRIGATION

Abstract

In the present study, salicylate (SA) and barley cultivars were investigated in managing drought stress in barley. The factors were irrigation at three levels including one-time irrigation (severe stress), two-times irrigation (moderate stress) and four times irrigation (control) and SA application at different growth stages including no foliar application and foliar application at stages 29, 34 and 39 of Zadoks Growth Stage (ZGS) and three barley cultivars including Khatam, Reyhan and Nosrat which were reported as semi-tolerant cultivars to drought. The findings showed that the interaction of reduced watering and SA increased chlora (8.8%) and b (7.12%) in the ZGS34 treatment at control conditions compared to the treatment without SA. The proline content increased with increasing drought stress, with the highest proline content obtained at the end of the tillering stage in the control condition. Compared to the control without foliar spraying, specific leaf area increased by 3.8, 1.8 and 0.4% respectively. Relative water content in Khatam (35.6%), Reyhan (33.3%) and Nosrat (30.5%) decreased with increasing stress in the control treatment compared to the minimum stress. The most sensitive cultivar to lack of irrigation was Khatam. The rate of yield increase by SA compared to the control was (10.33%) among the barley cultivars cultivated, the cultivar Reyhan had a comparative advantage in more measures, especially when applied at ZGS29. In conclusion, SA improved the drought tolerance of the barley and increased the yield by improving the biochemical characteristics.