Effect of Sowing Date and Plant Density on Some Agronomic Characteristics, Grain Yield and Its Components in Soybean Genotypes in Moghan Region

To study the effect of sowing date and plant density on some agronomic characteristics, seed yield and its components of soybean genotypes, a field experiment was conducted in Moghan Agricultural Research Center in 2007 and 2008 cropping seasons. The experimental design was split split plot arrangment in randomized complete block design, with three replications. The main plots included sowing dates; 15 June, 01 July, 16 Jul and 01 August, and sub-plots comprised of three soybean genotypes; Hamilton × Essex, L17 and Williams. Three plant densities 30, 40 and 50 plant/m2 were randomized in sub-sub plots. Combined analysis of variance for two years data showed that seed yield was affected by sowing dates. The highest and lowest grain yield were obtained from 15 June (3593 Kg/ha) and 01 August (2609 Kg/ha) sowing dates, respectively. There were significant differences among genotypes for agronomic characteristics and seed yield. By increasing plant density, plant height and number of seed per m2 increased, but number of pod per plant decreased. Density of 50 plants per m2 had the highest seed yield. Hamilton × Essex produced the highest grain yield (3784 kg/ha) in 15 June with 50 plants per m2.