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

Abstract

Genotype x 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 x 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 specific adaptations to high potential environments. Obatanpa was adapted to environments with low-yielding potential, since improvement of the environment did not improve its yield. ZM501 was the most stable genotype, and showed no significant yield difference to PAN 6479. ZM501 can therefore be assigned to several environments in the Eastern Cape.

Keywords: additive main effects and multiplicative interaction, AMMI stability values, genotype x environment interaction, yield stability

South African Journal of Plant and Soil 2014, 31(2): 61–68