Variabilidad genotípica de rasgos morfo-fisiológicos en líneas endocriadas de maíz. Análisis de la interacción genotipo x ambiente y su efecto sobre las decisiones de selección.

D'ANDREA, K.E.; OTEGUI, M.E.; DE LA VEGA, A.

Rosario, Santa Fe, Argentina

Congreso; VIII Congreso Nacional de Maíz.; 2005

A.I.A.N.B.A.

In maize (Zea mays L.) breeding programs, variations among genotypes associated with genotype x environment (G×E) interactions produce uncertainty in the selection process, and could complicate the effective identification of inbreds lines possessing the required attributes. The size and nature of the G and G×E interaction effects for plant grain yield and several physiological attributes (A) were examined for 12 maize inbred lines, all cropped in 4 environments represented by 2 years (Y) and 2 nitrogen (N) levels. Analyses of variance and 3-mode (G×E×A) PCA were performed with this data set. The G component was more important in attributes related to light capture, phenology and early biomass production. The G×E interaction explained most of the variability observed in traits related to yield determination, except for grain weight. Three-mode analysis model accounted for 63% of the variation. The first environment component described the G×Y interaction, and the second component the G×N×Y interaction. The unpredictable nature of these interactions implies that broad adaptation is required for a stable seed production among environments. Inbreds LP2 and LP662 showed relatively low interaction with the environment for plant grain yield and would constitute a source of broad adaptation. In contrast, inbred LP561 could be used as a source of specific adaptation due to its improved relative performance for plant grain yield in stress environments. Three-mode analysis allowed a better understanding of the influence of the environment on measured traits, and established the importance of G×Y y G×Y×N interaction effects for plant grain yield in the determination of kernel number, harvest index, and biomass production at maturity.