Vegetable Soybean Quality Physiological Study

The purposes of the study were to find impersonal factors definingvegetable soybean quality, according Which to choose good vegetablesoybean vareties and Study effects of nitrogen level on vegetable soybeanquality. 28 vegetable soybean varieties were planed in l999 and 2000 at theM of Huajiachi campus, Zhejiang University. The results were as follows:l. The quality characteristic of vegetable soybean can be divided intofOtir grouPs f aPpearance, eating quality, nutrition quality and sanitationquality. Vegetable soybean aPpearance traits include pod length, pod width,pod color, etc. Stlldy showed that it was pod length, pod width, l00-podweigh and l00-seed weight determined the grade of vegetable soybean. Theeating quality of vegetable soybean consists of sweetness, flavor, textllre andtaste. Studies showed that sucrose was responsible for its sweCtness, therefOreanalysis of sucrose colltellt was most important in evaluation the sweetness ofvegetable soybean. The textgre of vegetable soybean is rather comPlex innature, the hardness -- expressed as the fOrce required to break the vegetablesoybean seed -- is adoptCd tO evaluate the texture. Experiments showed therewas a significan correlation between the hardness of the seeds after boiling 7or 9 milllles in waer and the texfore score of vegetable soybean. Certain freeamino acids are suggested as major contriblltor to the taste of vegetablesoybean. Analysis of amno acid pattems of five varieties proved tha therewere significant correlations bCtWhen colltents of gllltamic, asparagine andtaste score. ColltCni of gllltamic, asparagine could be used to evaluatevegetale soybean taste. Vegetable soybean has bJgh nutritiona value, itsprotein colltellt is high. SuPerior to grain-type soybean, vegetable soybean isalso a good source of vitamin C. Cofltents of protein, vitC and its amino acidspercellt could be used to evaluate vegetable soybean nUtriiona value.2. Cluster analysis was used to estimate the divergence of theaPpearance quality of vegetable soybean varieties. According to the results ofCluster analysis, fOur vegetable soybean varieties with good aPpearancequality were found: Tai 75, KS,, S951 -- 23 and S954 -- 31. ExceptaPpearance, S951 - 23 and S954 - 31 also had good eating and nutritionalquality, they were the vegetable soybean varieties of good developingprospect.3. Correlation analysis betWeen aPpearance, eating quality and nutritionquality indicated that there was significant correlation between pod length,pod width, l00 pod weight and 100 seed weigh. The starch content ofvegetable soybean was negatively and significanly correlated with proteincontent (r= -- 0.7l2**), but positively and significantly correlated with vitCcolltCllt (r=0.476* ), there was a significanly positive correlation betweenseed hardness and protein content. Vegetable soybean varieties of highprotein usually had low starch and vitC contents, its seeds were hard. Sothere were divergence between vegetable soybean eating quality andnlltfitional quality, these difference must be noticed in order to selectvegetable soybean varieties of high general quality.4. The effects of nitfogen to vegetable soybean were differellt indifferent varieties. In vegetable soybean Huachen l8, except plan yield, theaPpearance and eating quality decreased after nitrogen aPPlication. So it hadbetter not to use nitrogen fertilizer when plaming vegotable soybean Huachenl8. Also some essental amino acids contents decreased, vegetable soybeanTai 305 had the highest plan yield when aPply l20kg nitrogen fertilizer perhectare, its pod size, sucrose and protein colltellt also increased to somedegree. It was bther to aPply nitrOgen fertilizer to imProve the quality ofvegetable soybean Tai 305.