ESTABILIDAD DE RENDIMIENTO EN HÍBRIDOS DE MAÍZ LIBERADOS EN ARGENTINA ENTRE 1965 Y 2010.

DI MATTEO, J.; CERRUDO, A.; FERREYRA, J.M.; ECHARTE, L.; ANDRADE, F.H.

Rosario

Congreso; Maíz HD-X Congreso Nacional de maíz; 2014

Mean maize grain yield was increased 115 kg ha-1 yr-1 from 1965 to 2011 in Argentina. Potential grain yield was increased around 0.73% during the last 45 years; testing inbred lines and hybrids in a large number of locations and under high plant densities could have also increased maize yield stability in Argentina. In addition, yield response to high plant densities could help to understand grain yield stability of genotypes released in different decades. The objectives of this work were (i) to estimate the tolerance to high plant densities, (ii) to determine the yield stability, and (iii) to relate the yield stability with the tolerance to high plant densities, for genotypes released between 1965 and 2012. Six hybrids were sown at 18 locations with a wide range of environmental condition. Each experiment was sown at 4 plant densities with 3 replications. Additionally, 5 experiments were conducted at EEA INTA Balcarce, with 8 hybrids released between 1965 and 2010 with a wide range of densities (1.5 to 20 pl m-2). Yield stability of each genotype was characterized by the coefficient of variation (CV) of grain yield across environments. Tolerance to high plant density of each genotype was characterized by (i) relative grain yield reduction when doubling plant density from its optimum, and (ii) the quadratic coefficient (B2) of the fitted equation to the relationship between grain yield and plant density. Mean grain yield across environments was higher and CV was lower in new than in older hybrids. Tolerance to high plant density increased across decades, because of the reduction in grain yield decreased linearly across decades and B2 increased linearly across the years. The tolerance to high plant densities was surrogate of yield stability.