PLANT CELL BIOTECHNOLOGY AND MOLECULAR BIOLOGY

Among several models proposed for evaluation of the G×E interaction, the AMMI and GGE-biplot are the most informative models. The objective of this study was to estimate the G×E interaction for grain yield/ha (GYPH) in 28 Egyptian maize hybrids and to identify genotypes of stability and/or adaptability across eight environments (combinations of the four plant densities 47,600, 71,400, 95,200 and 119,000 plants/ha× the two seasons 2019 and 2020) using AMMI and GGE-biplot analyses. A randomized complete block design was used in each environment with three replications. The AMMI analysis of variance indicated that the genotype (G), environment (E) and G×E interaction had a significant (p≤0.01) effect on maize GYPH. The hybrids SC-30K8, SC-375, TWC-368, TWC-373, SC-178 and SC-2088 showed the lowest ASV and IPCAg-1, but their GYPH was below average for SC-375, the lowest for TWC-373, above average for SC-30K8, SC-2088, TWC-368 and among the seven highest yielding genotypes for SC-178, which could be considered stable. SC-P3444, SC-P3433 and SC 235 ranked the first, second and third highest yielding genotypes, but attained moderate and high scores of IPCAg-1 and ASV, indicating that these hybrids could be identified as good genotypes to validate for yield performance and specific adaptability. The optimum environment was the lowest plant density (47,600 plants/ha) in season 2020; it was the most stable based on IPCAe-1, IPCAe-2 and ASV scores, indicated both good discriminating ability and representativeness, making it ideal and best environment for testing maize genotypes. Based on GGE-biplot method, SC-235was the winning genotype (most adapted) for the first mega-environment (low and moderate plant density environments), but SC-3444was the winning genotype for the second mega-environment (high and very high plant density environments). Further testing in additional environments and across more years is encouraged.