و لاين هاي والدي آن ها به خشكي با استفاده از شاخص هاي مختلف تحمل به تنش ZEAMAYSL. عكس العمل هيبريدهاي

Response of Corn (Zea mays L.) Hybrids and Their Parental Lines to Drought Using Different Stress Tolerance Indices

A Field experiment was conducted to study drought tolerance indices in corn genotypes for two years (1996 and 1997) at Seed and Plant Improvement Institute Experimental Station, Karaj, Iran. Three hybrids (SC704, SC711, and SC704M) and four parent lines (B73, B73 xB84, M017 and L105) with four stress treatments (without stress, stress at vegetative period, at anthesis period, and during kernel filling period) were studed in RCB design with three repleations. Among four estimated indices, i.e. mean productivity (MP), tolerance index (TOLL), stress susceptibility index (SSl), and stress tolerance index (ST1), the last index was more efficient than other indices in selection of genotypes under stress and non-stressed conditions. Among the genotypes, hybrid SC704 was more suitable for non-stressed conditions because of its high yield potential and hybrid SC704M was more adapted to stress condition. Hybrid SC711 showed the average performance of other two hybrids. Except parent B73 x B84, with high potential yield, the most tolerant line in this study was M017. Correlation between hybrids and their parents for yield and tolerance indices under optimum condition, were negative and weak, however, under stress conditions, there were positive and stronger correlations.