For Objective 1: Based on our nine years data analyses, we have the following conclusions: (1) Environmental (location) conditions played the largest role on yield (33~91%); (2) Seed providers had significant but small impact on soybean yield production (0.4~14.7%); (3) Differences among cultivars were important but not as environmental conditions (1~17%); and (4) Genotype-by-location interactions had some impacts on yield production, but not very large (2~23%).

For Objective 2, we found that correlation patterns between yield and agronomic traits varied among locations for both years, indicating that soybean yield production are related to different phenotypic traits. For example, plant height and biomass are more related to high yield in low yielding areas while yield components are more related to yield under high yielding environments. Stability analyses also showed the similar conclusion. Thus, based on our investigation, we conclude that phenotyping breeding should be considered to optimize soybean production in both low yielding and high yielding environments in South Dakota.