Resumo

BARRIOS-AYALA, Aristeo et al. Genotypes × crop management interaction effect on harvest index of corn hybrids under irrigation. INCI [online]. 2006, vol.31, n.7, pp.530-535. ISSN 0378-1844.

Six maize field experiments conducted in Southeastern Mexico in the 1997-99 period were analyzed in order to evaluate genotype × crop management interaction on harvest index (HI). The validity of using a constant value for HI is questioned in modern hybrids of corn, in order to predict its growth from some modular, dynamics models which are additives and ignores factor interactions. 25 and 27 treatments of a rotatable central composite design for N, P, K, population density and planting date were assigned to main plots of a split plot design replicated twice. Small plots were assigned to 3, 4 or 6 maize hybrids that had similar agronomic performance but differing genetic backgrounds. An interactive quadratic model for management factors and maize hybrids was fit by regression for harvest index (HI). Dummy variables valued 0 or 1 accounted for maize hybrids. Alternatively, a quadratic, additive model that ignored maize genotypes was fitted by regression. Results reflected genotype × management interaction that varied significantly among hybrids and locations in the interactive model, causing significant variation in HI. Extreme computed HI values were 0.32 and 0.60 for H-515 and Hemoc hybrids, respectively. The interactive model consistently improved 14 to 47% the determination coefficient (R²) for HI.

Palavras-chave : Índice de Cosecha ; Interacción Genotipo × Manejo; Híbridos de Maíz ; Modelo Cuadrático Aditivo ; Modelo Cuadrático Inaditivo.