Effect of gibberellic acid solution spraying on the source strength and stem storage of wheat cultivar

This study has been conducted to recognize some of the physiological mechanisms related to the storage in different wheat cultivars as a split-plot experiment in a randomized complete blocks design with three replications at the experimental farm of Agriculture and Natural Resources ofUniversity of Tehran in Karaj, during two crop years of 2014-2016. Experimental treatments consisted of 22 wheat cultivars as the main plots and gibberellic acid (GA3) at two levels (0 mg/L (control) and 100 mg/L) as the sub plots. Results showed that gibberellic acid spraying significantly increased stem dry and specific weights, leaf area, chlorophyll and grain yield in different wheat cultivars in both experimental years. Among these traits, the shoot dry weight had the highest response to gibberellic acid spraying. There was also a significant positive correlation between stem dry and stem specific weights and remobilization in different cultivars under gibberellic acid spraying condition. Shabrang and Dez cultivars had the highest storage related traits (stem dry and specific weights) under gibberellic acid spraying condition which resulted in higher grain yield. These cultivars had the highest grain yield due to higher stem reserves remobilization capacity. In this study, exogenous application of gibberellic acid has generally strengthened the stem storage capacity, source strength and yield in different wheat cultivars.