Agronomic and physiological response of maize (Zea mays L.) hybrids to plant density in the dry and wet Middleveld of Eswatini
Department of Crop Production, University of Eswatini, P. O Luyengo, M 205, Eswatini
*Correspondence: tamado@uniswa.sz
Abstract:
One of the factors limiting yield of maize in Eswatini is use of non-optimum plant density for the different maturity group of maize hybrids in different agro-ecologies. Thus, an experiment was conducted at Malkerns (wet Middleveld) and Luve (dry Middleveld) in Eswatini to determine the effects of plant density on growth, yield components and grain yield of maize hybrids. Factorial combinations of three maize hybrids [SC 403 (early maturing), SC 621 (medium maturing), SC 719 (late maturing)] and five plant densities (41,667; 44,444; 47,619; 50,000, and 57,143 plants ha-1) were evaluated in Randomised Complete Block Design in three replications. The results showed that Malkerns had significantly higher crop growth rate (CGR) between V12 and R6 growth stages, relative growth rate (RGR) between V6 and V12 growth stages, mass of thousand kernels (395.60 g), aboveground dry biomass (22.71 t ha-1) and grain yield (7.67 t ha-1). Among maize hybrids, SC 719 produced significantly the highest CGR (18.37 g m-2 per day) between V12 and R6, aboveground dry biomass (23.05 t ha-1), number of kernels per m2 (2074), and grain yield (7.49 ha-1). Moreover, SC 719 grown at Malkerns recorded significantly the highest leaf area index (LAI) at V6, and the highest CGR (31.35 g m-2 per day) between V6 and V12 and the tallest plants. The highest density of 57,143 plants ha-1 produced the highest LAI, aboveground dry biomass (21.53 t ha-1) and grain yield (7.17 t ha-1). Thus, late maturing maize hybrid SC 719 and plant density of 57,143 plants ha-1 (70 cm × 25 cm) can be used to enhance the productivity of maize in the Middleveld of Eswatini.
Key words:
crop growth rate, grain yield, leaf area index, relative growth rate, Swaziland, yield components