YIELD PERFORMANCE OF MAIZE HYBRIDS IN RIO GRANDE DO SUL HIDROMORFIC SOILS

The agricultural diversification in RS lowlands aims to qualify the productive system historically based on rice/cattle raising binomial. Maize is one of the grain crop alternatives to these areas; benefiting the system of rotation and amplifying the maize supply in RS state. The maize hybrids grain yield is influenced by environmental factors, which can interact with plant genotype. A study was carried out with the objective of identifying stable and/or responsive maize hybrids to grain yield in RS hidromorfic soils. It was used yield data (t ha-1) of a group of maize trials developed in fifteen environments in the agricultural period from 1995/96 to 2000/01. The stability was analyzed by an unbalanced discontinuous bi-segmented model (Storck, 1998). Each hybrid was classified by the comparison of its yield average with the average of all hybrids, in a function of parameters from discontinuous bi-segmented equation (b1 and b2) and in a function of adjustment quality (R2). AG 6018, P 30F33, P 30K75, DKB 215 and DKB 344 hybrids were indicated for intermediate environments; AGN 2012, AGN 3150, BRS 3060, and P 30R07 hybrids, for higher than intermediate environments, and AG 5011, G 800 and P 3063 hybrids were indicated for all environments, indicating that these are responsive hybrids. The other hybrids were not indicated due to low stability or low grain yield (below hybrids average, 5.704 t ha-1).