Evaluation of productivity and stability of elite summer soybean cultivars in multi-environment trials.

Spring soybean cultivars produced in moderate climates currently represent almost the entire soybean industry; however, soybean production has the potential to be extended into the summer months in different regions of the world. It is critical to select the correct soybean cultivar for production in a specific environment. The purpose of this study was therefore to evaluate the productivity (yield) and stability of the current summer soybean cultivars in multi-environment trials in the Huang-Huai-Hai region, presently the largest summer soybean-producing region in the world, to determine which cultivars will be most successful for large scale production in this region, as well as those that should be used in future breeding efforts. A total of 94 summer soybean cultivars were grown in the three major soybean production provinces, i.e., Shandong, Henan, and Hebei, over 3 years (2008-2010). The GGEbiplot™ software provided a 'genotype x genotype-by-environment interaction' function to evaluate the importance of agronomic factors controlling the soybean yield of each cultivar across the nine different environments. Xudou10, Zhonghuang39, Lu93748-1 and Lu99-1 exhibited relatively high average yields. The stability among the high-yielding cultivars was ranked in decreasing order as Xudou10, Zheng99048, Jidou7, Yudou18, and Gaozuoxuan-1. Among all recorded factors, the pod number per plant was the most important factor controlling yield, followed by seed number per plant, effective branch number, and 100-seed weight, which positively affected soybean yield. In contrast, a higher bottom pod height, greater number of nodes on the main stem, and longer growth duration were negatively correlated with yield. [ABSTRACT FROM AUTHOR]