Genotype x environment interactions and yield stability of stress-tolerant open-pollinated maize varieties in the Eastern Cape province, South Africa

Genotype × environment interactions are inherent in multilocational trials and complicate identification of superior genotypes. The aim of the study was to determine yield performance and stability of 13 maize genotypes in five locations of the Eastern Cape province, South Africa. The genotypes assessed were: ZM305, ZM423, ZM501, ZM525, ZM621, ZM627 and Obatanpa from the International Maize and Wheat Improvement Centre; BR993 and COMP4 from the International Institute of Tropical Agriculture; four local checks, AFRIC 1, Okavango, Nelson's Choice, and PAN 6479. Yield data were subjected to analysis of variance (ANOVA) and additive main effects and multiplicative interaction (AMMI) analysis. According to ANOVA, genotype × environment interaction was significant. PAN 6479 (5.21 t ha-1) and ZM525 (5.19 t ha-1) were the highest-yielding varieties, whereas Okavango (4.08 t ha-1) showed the lowest yield. Based on AMMI analysis, BR993 and Obatanpa were the least stable genotypes. PAN 6479 and ZM525 showed specifi...