Effect of Planting Date On Length of Growth Stages for Maturity Group IV – VIII Soybeans.

The objective of this study was to evaluate the influence of planting date on maturity group (MG) IV through VIII soybeans [Glycine max (L.) Merr.]. The 2-yr research was conducted at Clemson University, Edisto Research and Education Center near Blackville, South Carolina. The MG IV-VIII soybeans were planted approximately every two weeks starting after mid April and continued until end of July. Our results showed that earlier planted soybeans had longer durations of vegetative and reproductive stages. Later planting dates shortened the duration of these stages, especially for later MG soybeans. Decrease in the total length of vegetative growth most likely affected grain yields. Most MG soybeans yielded higher if planted in May, except MG IV, which yielded lower when compared to other maturity groups. Planting dates after early or mid June decreased yields of all MG soybeans.