Genotype x Environment Interaction and Yield Stability of Maize
AbstractMaize cultivars vary in their response to variable environmental conditions. Twenty maize cultivars were tested at nine locations in Ethiopia (1100 – 2240 masl) in randomized complete block design with three replications for two years to study the nature and magnitude of genotype x environment (G x E) interaction and phenotypic yield stability of the cultivars. Analysis of variance and stability analysis were computed. Variances due to genotypes, years, locations, genotype x year, genotype x location and genotype x year x location interaction were significant (P<0.01). Most of the cultivars had significant deviation mean square (S2di), implying that these cultivars had unstable performance across the testing environments. However, Additive Main Effect and Multiplicative Interaction (AMMI) analysis showed Gibe-1 (mean yield, 7.40 t ha-1) had relatively stable performance across the environments. None of the cultivars were the best for grain yield in all environments. BH-660 (mean grain yield, 8.14 t ha-1) had a relatively good performance in the mid- to high-altitude (1650 – 2240 m above sea level) areas whereas BH-140 (mean grain yield, 6.65 t ha-1) had a good performance in the low-mid to mid-altitude (1100 – 1650 m above sea level) areas, indicating the possibility of developing specific cultivars adapted to mid- and high- or low-mid and mid-altitude areas. However, the top yielding cultivars at each maize agro-ecology were specifically adapted, indicating that, for high yield potential in each maize agro-ecology, a specific breeding program is necessary.
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