Abstract: 【Objective】The research compared the morphological, yield, and quality traits of soybeans [Glycine max (L.) Merr.] cultivars developed in different years from different breeding programs of Ohio, U.S.A. and Liaoning, China, which were at the same latitude. The purpose of this study was to reveal the evolutionary trend of the main agronomic traits, and the response to the fertilizer rate with the seed yield improvement.【Method】The field experiment was conducted in 2011, 2013, and 2014, and used a completely randomized design with three replications. The diammonium phosphate was applied as starter fertilizer, and had three levels (0, 150, and 300 kg·hm^-2). The main agronomic traits, seed yield, and quality were measured at the mature stage.【Result】With the improvement of the soybean yield of Liaoning and Ohio cultivars, plant height, internode length, and lodging score decreased, harvest index increased; the branch and height of the lowest pod of Ohio cultivars increased, and that of Liaoning cultivars was decreased. The improvement of seeds per plant was the main reason for the yield increasing of Ohio cultivars, and the main factor for Liaoning cultivars was of a bigger 100-seed weight. In the process of cultivar development, the protein content of Ohio cultivars decreased, while the fat content increased; the protein content of Liaoning cultivars increased, and there was no significant changed in fat content. Compared with Liaoning cultivars during the same period, the plant height, internode length, and lodging score of Ohio cultivar decreased; and pods per plant, seeds per plant, harvest index, and yield increased; protein content decreased, and fat content increased. With the increment of the fertilizer rates, the plant height, internode length, and lodging score of the Ohio cultivar remained relatively stable, but that of Liaoning cultivars increased sharply; the yield of Ohio cultivars increased with the fertilizer rates, and the yield of Liaoning cultivars was highest at the medium fertilizer rate. The results of correlation and path-coefficient indicated that the yield was significant negatively correlated with plant height, internode length, and lodging score; while it was significant positively correlated with seeds per plant and harvest index, and plant height, seeds per plant, and harvest index had a greater direct effect to yield improvement.【Conclusion】During the improvement of the soybean yield of the Ohio and Liaoning cultivars, the plant height and internode length decreased, the lodging resistance and harvest index increased, but the improvement progress of the Ohio cultivars was greater than that of the Liaoning cultivars. The yield improvement of the Ohio cultivars was mainly attributed to the increment of seeds per plant, and that of Liaoning cultivars was a bigger 100-seed weight. The fertilizer tolerance of the Ohio cultivars was enhanced, and the plant height and lodging score kept stable by the fertilizer rates rising, but that of the Liaoning cultivars increased.

Key words: soybean, morphological trait, yield, quality, genetic improvement, fertilizer tolerance, China, USA