Valor nutritivo do colmo de híbridos de milho colhidos em três estádios de maturidade

Abstract

The objective of this work was to evaluate the effect of plant maturing on the stalk nutritional quality of corn hybrids, in order to define selection criteria in breeding programs of maize for silage. Fifteen hybrids from the Instituto Agronômico breeding program in Campinas, SP, Brazil, harvested at 90, 120 and 150 days after germination, were evaluated in a randomized block design, with three replicates. The fourth and fifth stalk internodes were removed for determination of chemical composition and in vitro digestibility. In both internodes, fiber content decreased and lignin content increased as maturity advanced. Dry matter digestibility of the fifth internode increased with maturity, while there was no change in the fourth internode. Maturity reduced neutral detergent fiber digestibility (DIVFDN) of the fourth internode but not of the fifth one. The forth internode DIVFDN can be used as a selection criterium for nutritional quality improvement of corn hybrids. There was great genetic variability of quality parameters, among harvested hybrids at the three maturity stages, which highlights the possibility of implementing breeding programs for nutritional quality of corn for silage.