Agronomic performance and stability of soybean varieties grown in three maturity zones of Minnesota

Soybeans grown in Minnesota average 1.1 percentage points less protein and 0.7 percentage points more oil than the U.S. average at 13% moisture. There are concerns about these discrepancies, but the reasons why northern latitude soy-beans are lower in protein concentration are not well defined. An important research goal is the development of high yielding soybean varieties with improved protein concentration and good stability of production characteristics. To reach this goal, an improved understanding of the relationship between varieties, environmental conditions, and variety x environment interaction are needed. Additionally, an understanding of the relationships between small research plots and large production fields are needed in order to make recommendations for high yielding, high protein varieties. Variety stabilities, in addition to variety means, have to be analyzed in order to understand the above relationships. Two nonparametric stability measures based on variety ranks and Kang's yield-stability statistic are three examples of stability statistics that can easily be computed and compared among varieties adapted to a specific growing region.