Correlation and path coefficient analysis of various agronomic traits in barley under drought stress and non-stress conditions

In order to study of relationships between various agronomic traits and their influences on barley grain yield, two separate experiments were carried out in a randomized complete block design with three replications. Treatments were genotypes including Gorgan4, Nosrat, Reyhan, Makoii, Valfajr, Zarjou, Gorgan, Kavir, Esterain and Nimruz. The experiments were under drought stress and non-stress: stopping the irrigation at blooming stage till complete maturity stage conditions. The correlation coefficients were significantly positive between grain yield and days from emergence to physiological maturity, plant height, culm thickness, biological yield, kernel length and spike weight under non-stress condition. Days from emergence to physiological maturity, plant height, biological yield, kernel length, kernel thickness, spike weight and 100-grain weight significantly positively correlated with grain yield under stress condition. Using stepwise regression, spike weight, 100-grain weight and days from emergence to physiological maturity, spike weight, kernel length, spike length, kernel thickness and biological yield as independent variables, model determination coefficients were R2=0.83 and R2=0.91 under non-stress and stress conditions, respectively. path coefficients analysis showed that direct and indirect effects of spike weight on grain yield were the highest and positive under non-stress and stress conditions, indicating that direct selection to improve grain yield with this trait would be effective.