Effect of water stress on yield, yield components and photoassimilates partitioning of barley cultivars (Hordeum vulgare L.) in reproductive stage

Available water is an important factor for plant growth in arid regions and dry matter remobilization from different parts of the plant stem has an effective role in drought tolerance. In order to assess the effect of drought stress in flowering stage of barley, a field experiment was carried out in a split-plot based on randomized complete block design with three replications in Ahar in 2018-2019. Irrigation treatments included normal irrigation and irrigation up to the flowering stage in main plots and barley cultivars (Sahand, Bahman, Makui and Valfajr) were placed in subplots. The results showed that weight of thousand grains of cultivars decreased under stress conditions by 21.45% compared to normal irrigation. Makoei cultivar had the highest decrease in grain yield with 23.55% reduction compared to other cultivars. The highest decrease was belonged to Bahman and Makoei in biological yield. The highest amount of biological yield was observed in Bahman under normal irrigation conditions. The rate of remobilization increased in different stem internods and different cultivars. Penultimate remobilization was higher than peduncle in Valfajr and Sahand cultivars. Bahman and Makui cultivars had high remobilization rate from peduncle and lower stem internodes. The remobilization efficiency of different stem internods had a significant increase under stress condition and the highest contribution of peduncle remobilization was related to Sahand under drought stress conditions.