Effect of Planting Date On Soybean Shattering and Seed Quality in Different Maturity Groups.

The maturity group (MG) IV soybeans are adapted to the Early Soybean Production System in Mississippi and Midsouth USA. However, seed quality, including shattering is still a major problem associated with this system. Previous study indicated that seeds of most MG IV soybean varieties planted at late April can stay in the field before harvesting for approximately three weeks before it gets into serious shattering. Studies were continued at the Delta Research and Extension Center, Stoneville, MS, with 80 and 134 varieties in 2008 and 2009, respectively. Results indicated that the maturity date, partially influenced by planting date, was critical to shattering trait. Soybean MG IV variety planted and matured at a later time had a much less shattering problem compared with those planted earlier. An early MG IV soybean matured in early September delayed its shattering up to five weeks or longer. The study on the physiological mechanism on how planting date affects seed shattering of MG IV soybeans and its seed quality in MS will be continued in 2010 and results are expected to be obtained at the end of the experiments and presented.