Effect of foliar application of zinc sulphate on quantitative and qualitative traits of soybean in Khorramabad region, Iran

Effect of spraying zinc sulphate (ZnSo4) on yield and yield components of three soybean varieties wasstudied. A factorial experiment based on a randomized complete block design with four replications was carried out at the Islamic Azad University Research Farm, Khorramabad region, in 2009. Factors were three varieties of soybean named, m7, m9, L17 and zinc sulphate solution spray at three levels of 0, 0.002 and 0.004 kg/l that applied at flowering and pod stages. Characteristics like seed yield, biological yield, oil percentage, oil yield, number of nodes per stem, average length of mid-node and harvest index were measured. The results showed that genotypes had a significant effect (p≤0.01) on seed yield, oil yield and biological yield (p≤0.05). Comparison of means (using Duncan's multiple range test) indicated that the highest seed yield (2130.9 kg /ha) and biological yield (2452.3 kg/ha) were obtained for the variety L17. The effect of different levels of ZnSo4 spraying and their interaction with variety showed significant differences (p≤0.05) on oil percentage and its value was reduced. The main effect of zinc sulphate spraying, variety and their interactions were not significant for the traits like stem diameter, number of nodes per stem, average length of mid-node and harvest index. Indeed, application of zinc sulphate solution on seed yield was not statistically significant.