M. R. Shiri - Agricultural and Natural Resources Research Center of Ardebil Province, Moghan, Iran.

Drought stress is the most important environmental constraint contributing to grain yield instability of maize(Zea mays L.). Evaluation of maize genotypes under different stresses would be useful for identifying genotypes that combine stability with high yield potential for stress-prone areas. This study was conducted to estimate grain yield stability of maize hybrids and to identify hybrids that combine stability with high yield potential across stress and non-stress environments. Seven maize hybrids were tested in three consecutive growing seasons under four irrigation regimes (E۱ = well-watered; E۲ = water deficit at the vegetative growth stage; E۳ = water deficit at flowering; E۴ = water deficit at grain-filling) at Ultan Agricultural Research Station, Moghan, Iran. Combined analysis of variance showed that environments, genotype and genotype × environment (GGE) interaction effects were highly significant. Genotype and genotype × environment analysis using GGE biplot explained ۹۴.۷% of the total grain yield variation. The GGE biplot analysis ranked maize hybrids with above-average yield across growing seasons (SC۷۰۴ > SC۷۲۴ > SC۷۰۳ ≈ SC۷۲۰ > SC۶۴۷) and grain yield stability (SC۷۰۰ > TWC۶۰۰ > SC۷۲۴). According to the variation in maize hybrids as well as G × E interaction sources, hybrids SC۷۰۴ and SC۷۲۴ in environments E۱, E۲ and E۴ as well as hybrid SC۶۴۷ in E۳ were the superior hybrids and had better specific adaptation. The hypothetical ideal genotype's biplot indicated that hybrid SC۷۰۴ had higher grain yield and yield stability and was better adapted to all the test environments.

Drought Stress, ideal genotype, Specific Adaptation, vegetative growth stage, Yield stability