Variação genética da composição química e digestibilidade do colmo de genótipos de milho colhidos em três estágios de maturidade

Abstract

DEDICATÓRIANowadays there is the recognition that selection criteria that favors grain production can be undesirable for nutritional value of corn silages. Corn hybrids for silage should mature slower with gradual decline of plant moisture, have softer grains and stalk with high fiber digestibility. Therefore, it was our objective to evaluate the effect of age of harvest on the stalk nutritional quality of corn hybrids, aiming to define selection criteria in breeding programs focused on improving the stalk fiber digestibility. It was still our objective the classification of genotypes in groups according to their production and nutritional qualities. internode increased with maturity, while there was no change in the 4 th internode. The fiber digestibility of the 4 th internode was reduced with advanced maturity while there was no effect on the 5 th internode. Fiber digestibility of the 4 th internode was negatively correlated with lignifications, while this correlation was inexistent for the 5 th internode, indicating that the 4 th internode could be used as an indicator of the decrease in stalk fiber digestibility that occurs with advanced maturity of corn hybrids. There was great genetic variability among the 15 genotypes in the three stages of maturity for the quality parameters, highlighting the necessity of careful selection of the material to be used for silage production and the possibility of implementing breeding programs focused on improving the nutritional quality of corn hybrids for silage.