Component Plant Part Development in Maize as Affected by Hybrids and Population Density

Abstract

AbstractMaize (Zea mays L.) is used extensively as a silage crop. A relatively simple method is needed to evaluate hybrids for that purpose. Six maize hybrids, two each in early, midseason, and medium‐late maturity classes, were grown at four population densities over a 3‐year period. The hybrids were chosen on the basis of superior grain yield for their respective maturity class in previous tests. Populations were established at 34,600, 44,500, 54,300, and 64,200 plants per hectare. Data were obtained for each hybrid at each planting rate for grain and forage yield and on several other traits, including component plant: part ratios.The early hybrids tended to be lower in grain yield, total dry weight, weight per ear, moisture at harvest, ear height, plant height, and proportion of stalks but higher in proportion of ears than the later hybrids. Shelling percentage, proportion of leaves, and stalk diameter showed differences between hybrids but no trend among maturity groups.As population densities increased, total dry matter increased, whereas weight per ear, stalk diameter, and percent erect plants decreased. Plant and ear heights changed very little with changes in population density. Plants tended to become proportionately smaller as populations increased so that plant‐part ratios remained nearly the same. Barren plants were not included in the separation samples. Percent barren plants increased significantly with increased population density.High energy feeds are needed by high‐producing, lactating cows and cattle on finishing rations. Maize parts vary greatly in digestibility. In the absence of feeding trials, plant‐part separation data and total dry matter production may be the most useful indicators of the relative values of maize hybrids for silage.