AGRONOMIC PERFORMANCE OF MAIZE CULTIVARS AT FOUR MANAGEMENT SYSTEMS

Grain yield determination of maize cultivars under different growing conditions is important to assure correct management decisions. This work was carried out aiming to evaluate the agronomic performance of maize genotypes with different genetic basis under contrasting management systems. The experiment was performed during the growing seasons of 2001/2002 and 2002/2003 in Eldorado do Sul-RS, 2002/2003 and 2003/2004 in Lages-SC. The single-cross hybrid P32R21, the double-cross hybrid Traktor, and the open-pollinated variety BRS Planalto were assessed. Each genotype was grown at four management systems: low, medium, high and very high. The systems differ in relation to plant population, row spacing, fertilization, and irrigation. Grain yield ranged from 1.8 to 15.4 t ha-1, increasing with the enhancement in management level, regardless of cultivar. Enhancements in grain yield were mostly due to the increase in kernel number per square meter. Differences in grain yield between the single-cross hybrid and the other genotypes were larger at the higher management levels. The openpollinated variety BRS Planalto did not present higher grain yield than the hybrids in the systems with low and medium investments in management