Study of growth pattern and seed yield of two soybean cultivars in delay cropping in Karaj region

In order to study the growth pattern and seed yield of two different growing type of soybean in delay cropping in Karaj region, an experiment was conducted during the 2000-2001 growing season at the Agricultural Experimental Farm of Tehran University. The experimental design was a factorial with 3 replications in which the first factors were 3 different plant densities (20, 40 and 80 plant per 1 m2). Second factors were two different growing types of soybean cultivars (Hag: 3 type and Clark 63: 4 type). The sowing date in two cultivars was the same and it conducted in 21 May. Study the growth pattern showed that, the maximum total dry matter, leaf area index (LAI) and crop growth rate (CGR) achieved in 80p/m2 and than decreased with low density. The growth pattern in all treatment increased up to 85 day after planting and than deceased. The chances of leaf area index and crop growth rate were the same in two cultivars, already. In other hands the maximum relative growth rate (RGR) was observed in 20p/m2 in 40 day after planting. The results of seed yield showed that the effects of density on seed yield were different significantly in 1% levels. In this study the highest yields obtained in 80 p/m2 in hag and Clark as 66/4282 and 12/4464 respectively. The number of pods in plant decreased significantly when plant density increased. According to the results number of seed in pods unaffected significantly by density and cultivars. Weight of 1000 seeds was affected by plant density and cultivars. As by increasing the plant density, weight of 1000 seeds increased.