Yield stability and relationships among parameters in maize

Abstract

Producing high yielding maize (Zea mays L.) hybrids well-adapted to many environments is the most important goal of the National Maize Research Program in Egypt. Genotype x environment interaction (GEI) continues to be a major challenging issue to plant breeders and production agronomists. The objective of this study was to identify maize hybrids with stable and high yield performance across different location under Egyptian conditions. Five yellow single crosses (SC Sk-149, SC Sk-150, SC Sk-151, SC Gm-111 and SC Gz-312); three red single crosses (SC Sk-1 Red, SC Sk-2 Red and SC Sk-3 Red); and two yellow commercial hybrids (SC 162 and SC 168) were evaluated at five sites in Egypt. Stability parameters for grain yield were performed to estimate both regression coefficient (bi), deviation from regression (S2di) and coefficient of determination (R2). Results showed that mean squares due to environments (E), hybrids (H) and their interaction (H × E) were significant, or highly significant for all traits. The best hybrids were SC Sk-3 Red for earliness, SC Gm-111 for highest plant; and SC Sk-149 and SC Sk-2 Red for resistance to late wilt disease. Superiority percentage for grain yield of two yellow promising crosses SC Gm-111 (22.78 and 19.69%) and SC Sk-150 (11.00 and 8.21%) were significantly out yielded the two checks SC 162 and SC 168, respectively. Four hybrids can be considered stable for grain yield based on the regression coefficient; as well as five hybrids based on deviation from regression and eight hybrids depending on coefficient of determination. Hybrids SC Sk-150 and SC Gm-111 had high grain yield and stable for R2. Mean grain yield was significant and positively correlated with S2di; but not significant with bi and R2. Also, R2 was significant and negatively correlated with S2di, but not significant with bi also bi or with S2di.