Effects of planting date and plant density on yield and some physiological characteristics of single cross 550 hybrid maize as a second crop

Maize grain yield has a high potential and as planting late maturing cultivars is delayed for any reason, middle-aged maize cultivars can be used as an alternative plant. Observing planting date and plant density is very important in increasing maize yield. In 2019 in Koohdasht City, Iran, a statistical design of split plots was performed based on complete blocks with three replications.  The aim of this study was to investigate the effect of density (6, 7, 8 and 9 plants m-2) and planting date (6, 13 and 20 July) on grain yield and its components in single cross maize cultivar 550.  Planting dates were considered as main plots and planting densities were considered as sub-plots.  By increasing density, traits such as number of leaves per plant, number of leaves above maize, stem diameter, maize diameter, maize length, number of grains per row and 1000-grain weight decreased.  By delay in planting, plant height, number of leaves per plant, maize length, stem diameter, maize diameter, number of grains per row and 1000-grain weight decreased.  The highest grain yield (14.313 tons per hectare) was obtained from the first planting date (6 July) with a density of 9 plants m-2.  By elevating density, plant height, maize height, grain yield, biological yield and degree of fruiting increased and the number of rows per maize, number of grains per row, maize diameter, cob diameter, stem diameter and 1000-grain weight decreased.