Studies Of Soybean Functional Component Distribution Across China And Analysis On The Environmental Influences

In addition to protein and oil,soybeans also contain some functional components which are beneficial to human health.Contents of functional components in soybean seeds are not only genetically controlled but influenced by environmental condition.However,the current level of functional components in soybean cultivars in China and its controlling environmental factors are not yet clear.In this study,the functional components were quantified in 1792 soybean samples collected from widely distributed regions across China from 2010 to 2017.The variations of isoflavones,saponins,phospholipids,dietary fibers,oligosaccharides,tocopherols,carotenoids,and their major components were analyzed.Compared with protein and oil,the variation of functional components of soybean in China is more abundant.A group of high-quality soybean cultivars rich in one or several functional components were selected for functional soyfood processing enterprises in China.The regional variations of functional components were analyzed.Geographic distribution analysis of functional components were performed by using the Kriging interpolation method in GIS,and advantageous growing areas of soybeans rich in different functional components were identified.Soybeans with high-level phospholipids,saponins,and carotenoids are mainly distributed in the northern region of China.The cultivars with high-level total oligosaccharide concentrated in the central region,and soybeans with high dietary fiber content mainly distributed in the southern region in China.The correlation and path-coefficient analysis between seed functional components and weather data during soybean reproductive stage were conducted.Total isoflavones(TI),phospholipids(TP)and oligosaccharides(TO)were negatively correlated with cumulative temperature above or equal to 15 ?(AT15)and mean daily temperature(MDT),but positively correlated with diurnal temperature range(DTR)and hours of sunshine(HS).Total saponins(TS)were negatively correlated with MDT but positively correlated with rainfall(RF),whereas TO were negatively correlated with RF.Dietary fibers(DF),was negatively correlated with DTR and RF.Total carotenoids(TC),was negatively correlated with MDT and HS but positively correlated with DTR and RF.Path-coefficient analysis showed that,temperature and HS during the reproductive period influenced TI and TP contents,while temperature and RF influenced TS and TO.TC was directly affected by DTR.The effects of weather factors on soybean functional components in diverse regions of China were characterized.The main weather factor affecting soybean functional components in NESR are DTR,HS in NWSR,RF in HHHR and DTR in SMCR.Based on the geographical distribution of soybean functional components,weather conditions and cultivation systems,the soybean production areas in China were divided into 3 regions and 10 subregions:Region I,North Spring Soybean with High Functional Component Region,including the North Northeast Spring Soybean with High Functional Component Subregion(Subregion ?1),Middle and South Northeast Spring Soybean with High Functional Component Subregion(Subregion ?2),North China Plateau Spring Soybean with High Oligosaccharide and Vitamin Subregion(Subregion?3)and Northwest Spring Soybean with Balanced Functional Component Subregion(Subregion ?4);Region ?,Huang-Huai-Hai Summer Soybean with Balanced Functional Component Region,including North Huang-Huai-Hai Summer Soybean with High Vitamin Subregion(Subregion ?5),South Huang-Huai-Hai Summer Soybean with Balanced Functional Component Subregion(Subregion ?6),South Multiple Cropping Soybean with High Dietary Fiber Region(III Region),including Middle and Lower Reaches of Yangtze River Spring and Summer Soybean with High Dietary Fiber Subregion(Subregion ?7),Southwest Spring and Summer Soybean with High Isoflavone and Dietary Fiber Subregion(Subregion ?8),Central South Spring and Autumn Soybean with High Dietary Fiber Subregion(Subregion ?9)and South China Multiple Cropping Soybean with High Dietary Fiber Subregion(Subregion ?10).With referencing the geographical distribution of soybean protein,oil,fatty acids,the integrated scheme of soybean quality regionalization in China were proposed based on the soybean functional component regionalization and the previous soybean quality division.The soybean production area in China was divided into 3 regions and 10 subregions,which was the North Spring Soybean with High Oil and Functional Component Region(I Region),including the North Northeast Spring Soybean with High Functional Component Subregion(?1 Subregion),Middle and South Northeast Spring Soybean with High Oil and Functional Component Subregion(?2 Subregion),North China Plateau Spring Soybean with High Oligosaccharide and Vitamin Subregion(I3 Subregion)and Northwest Spring Soybean with High Oil Subregion(I4 Subregion),Huang-Huai-Hai Summer Soybean with High Protein Region(? Region),including North Huang-Huai-Hai Summer Soybean with High Vitamin Subregion(?5 Subregion),South Huang-Huai-Hai Summer Soybean with High Protein Subregion(?6 Subregion),South Multiple Cropping Soybean with High Protein and Dietary Fiber Region(III Region),including Middle and Lower Reaches of Yangtze River Spring and Summer Soybean with High Protein and Dietary Fiber Subregion(?7 Subregion),Southwest Spring and Summer Soybean with High Protein,Isoflavone and Dietary Fiber Subregion(?8 Subregion),Central South Spring and Autumn Soybean with High Protein and Dietary Fiber Subregion(?9 Subregion)and South China Multiple Cropping Soybean with High Dietary Fiber Subregion(?10 Subregion).This study will be helpful in promoting soybean production for functional food purposes.