Investigating the Effect of Various Seed Rates on Phenological Characteristics, Yield Components and Seed and Oil Yields in Soybean Cultivars in Mazandaran Province

Abstract

To investigate the impact of various amounts of seed rates on phenological characteristics, yield components, seed and oil yields for soybean cultivars, this experiment has been conducted in split plots in the form of randomized complete blocks with four replications in a farming field in 2013. The seed rates of 55, 70, 85 kg/ha were considered as the main factor and the soybean cultivars as the sub factor in Sari (JK), Telar (BP), Caspian (033), Nekador (032), Katul (D.P.X), and Sahar (Pershing).The results have shown that the seed rates can influence significantly all the characteristics except the number of seed in pod. In this regard, the traits like the distance of first pod from the earth surface and the number of pods in main stem increase as the rate of consumed seed increases. As a result, the number of pods in plant and 1000-seed weight decreases. Since interaction effect of seed rate and cultivar was not significant for all characteristics except the height of first pod from surface and the pods' number in main stem, it means that changes in these characteristics have a similar progress except characteristics at the given seed level. Average seed yield of genotypes for three seed levels of 55, 70 and 85kg/ ha are respectively 2999, 3246 and 2700 kg/ha which are statistically divided in two groups. Among the genotypes, the cultivar of Nekador performs a better the highest seed yield due to its seed yield components. The seed yield amount of this value in three seed levels in 55, 70, and 85 kg/ha are respectively 3766, 3643, and 3496 kg/ha which its value was in the same class for 55 and 70 kg/ha seed rates. Seed rates had not significant effects on days to maturity. Sahar and Katul with 135.3 and 156.9 days to maturity, respectively which were considered as early and late maturity genotypes. Significant positive correlation of seed yield with the characteristics including pods per plant and 1000-seed weight, indicating the important role of these two yield components for seed yield increasing.