Abstract

Double cropping is a kind of multiple cropping system in which a second crop is planted after the first has been harvested. In order to study the yield of soybean (Glycine max L.) cultivars in double cropping with different densities, an experiment was conducted at Gonbad College of Agricultural Research Field of Gonbad High Educational Center (Iran). The treatments were factorial of cultivars (Williams, Gorgan 3 and Pershing) and three plant densities of 66.66, 40 and 28.75 plants m^-2 that were carried out with three replications. Plant height, pod number per plant, seed number per pod and seed yield was measured. Overall, the lowest plant density provided the greatest yield. However interaction between cultivars and densities was significant and maximum yield was obtained with the Pershing cultivar at the medium plant density (3232.02 kg ha^-1). The maximum yield was obtained by using low density.

Key words: Density, double cropping, soybean, yield.