Regional Distribution of Protein and Oil Compositions of Soybean Cultivars in China

Soybean [Glycine max (L.) Merr.] seed, which contains high levels of oil and protein, is one of China's most important native crops. The aim of this study was to investigate how regional and environmental factors affect the compositions of protein, amino acids, oil, and fatty acids. A total of 127 soybean cultivars from four main regions of China were analyzed. The levels of total protein and most of amino acids showed a trend of increasing from Northern to Southern China, while the levels of total oil, stearic acid, linolenic acid, and proline showed a trend of decreasing. The variation of protein, oil, palmitic acid, and linoleic acid content of soybean grown in the four regions was low, while variation of other constituents remained high. Most amino acids contents were positively correlated with protein content. The total oil content showed a negative correlation with protein content. The content of linolenic acid was positively correlated with the content of palmitic acid and stearic acid but negatively correlated with the oleic acid content. The southern regions have the potential for high-protein soybean production, while the northern regions of China have the potential for high-oil soybean production.