Evaluation of maize hybrids types harvested at the similar stage of maturity

Abstract

The agricultural practice requires more detailed and accurate research data and information. For farmers, the right choice of a proper maize hybrid has a decisive importance. The properties of the hybrids differ above all depending on the earliness, the type of the plant (stay-green vs. normal ripening), the type of the grain (flint vs. dent) or the type of the recommended usage (silage making vs. grain production) as well as by their intertypes. However, under practical conditions, some properties of the hybrids as declared by their sellers are not manifested.The effects of the type of maize hybrids and their maturity stage on their yields and nutritional characteristics were presented by several authors, e.g. by Pilipavicius and Mikulioniene (2010) or Hetta et al. (2012). Cone et al. (2008) demonstrated that not only yields and nutritional parameters, but also the degree and the rate of in vitro rumen fermentation were significantly influenced by the growth stage and the content of dry matter (DM) in the entire plants at the moment of their harvest. For the same type of hybrid (i.e. stay-green) the stage of maturity of grain and the whole plant DM is closely related. When comparing with each other the different types of hybrids (e.g. stay-green and dry down), this relationship may be different. Differences in DM content, nutrients and digestibility are also given by proportion grain (ear) to the other parts of the plant. According to Ettle and Schwarz (2003), the constituents of the ear (dehusked) and residual plants are affected by maturity stage but not by type of hybrid.However, if the hybrids showed a different degree of earliness on the day of the harvesting, they may be considered to be at different stages of maturity showing different contents of DM. This fact could be the reason why the declared properties ABSTRACTThe objective of the experiments was to compare types of maize hybrids harvested at the similar stage of maturity, between one and two thirds of the milk line stage of grain. The study involved 9 hybrids with different parameters that were grown during a period of three subsequent years in two locations with different level of precipitation. Differences in terms of the content of dry matter between the hybrids at different timing of harvests were small (323 ± 22 g/kg), showing no statistical significance (P = 0.34). Comparing the early maturity hybrids with the medium early hybrids (P < 0.05), the former showed a lower content of starch (299 g/kg dry matter (DM)), and the latter showed a slightly higher value (312 g/kg DM) -while the measured proportion of neutral detergent fibre (NDF) among these two hybrids was 453 vs. 428 g/kg DM. Comparing the measured value of the normally ripening hybrids against the stay-green hybrids, the starch was 314 vs. 294 g/kg DM, and NDF was 434 vs. 451 g/kg DM, respectively. As for the comparison between the flint (vitreous) type of grain endosperm vs. dent (floury), measured value of the starch was 298 vs. 323 g/kg DM, and NDF was 451 vs. 427 g/kg DM, respe...