Response of Soybean Varieties to Different Planting Dates

This experiment was conducted at a Research Farm in Shahriar, Iran, to study the effect of planting dates on agronomical and physiological features of some soybean varieties. Experimental design was a split plot in the form of randomized complete block design with four replications. Treatments included four planting dates with intervals of 10 days as main plot (May 20, May 30, June 9 and June 19) and four soybean varieties as subplot (Williams, Zan, L17 and M7). Traits such as the number of kernels and pods, protein and oil content, seed yield and pod yield were measured. Results indicated that the effect of treatments and their interactions significantly affected all traits (at p 0.01); the only exception was pod shell weight which showed no response to the interaction of planting date × variety. Overall, results of the experiment showed that the planting date May 20 and the variety Williams yielded better than other treatments.