Study of drought stress of hybrid corns (Zea mays) using drought tolerance indices

In order to investigate drought tolerance of maize hybrids, a split plot experiment was conducted in a randomized complete block design (RCBD) with three replications in the research field of Payame Noor University (PNU) of Kermanshah in 2013. The main factor included drought stress (stress and normal condition) and sub factor including nine corn hybrids. The results of analysis of variance indicate the different reaction of the hybrids studied for grain yield and the ability to select hybrids based on yield. Comparison of numerical values ​​and rank of each hybrid based on grain yield based on grain tolerance index showed that hybrids number one, three, seven and eight were identified as drought tolerant hybrids.Results of correlation analysis showed that MP, GMP, STI, HAR, K1, K2, SSPI and YI had positive and significant correlations with Yp and Ys.They are suitable for choosing high yield hybrids in both conditions. Gabriel's bi-plot drawing was performed based on the analysis of the main components. Based on this breakdown, the first two components justify about 98 percent of the variance. The results showed that the studied hybrids were located in two groups of high yield potential and weak potential, so that hybrids number one, three, seven and eight were placed in the vicinity of drought stress tolerance vectors as superior hybrids. The cluster analysis, based on the superior indices of the studied hybrids grouped the hybrids into two clusters that are similar to the Gabriel bi-plot.