Edible Quality and Its Regulation in Vegetable Soybean (Glycine Max (L.) Merr.).

Edible quality and its regulation in vegetable soybean (Glycine Max (L.) Merr.)

Qiuying Zhang*, Yansheng Li, Xiaobing Liu

Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, 150081, China 

*Corresponding author: zhangqiuying@iga.ac.cn

The present study analyzed the correlations between seed chemical compositions and edible quality in vegetable soybean. The accumulation of main quality compositions (sucrose, protein, oil, free amino acid, fructose + glucose, raffinose and stachyose) and regulation by key enzymes were investigated; the effects of nitrogen/potassium fertilization rate and planting dates on edible quality as well as key enzymes activities were analyzed. The cumulative contribution of sucrose, fructose + glucose, raffinose, stachyose, protein, free amino acid and oil to edible quality was 67.8%. The sucrose, free amino acid and protein contributed 25.7%, raffinose, stachyose and oil contributed 25.2%, and fructose + glucose contributed 16.9% to the edible quality. A significant positive relationship was found between edible quality score and sucrose content (0.864**), while a significant negative relationship was found between edible quality score and protein content (-0.439*). The changes of sucrose phosphate synthase (SPS), sucrose synthase (SS), acid invertase (AI) and neutral invertase (NI) activities were consistent to the changes of sucrose content during seed filling. Variety with higher seed sucrose content constantly had highest key enzymes activities and faster sucrose metabolic rate. The difference of sucrose synthesis enzyme activities (SPS) and sucrose decomposition enzyme activities (SS+AI+NI) was positively correlated with seed sucrose accumulation (r=0.530^**). Excessive N application not only reduced the fresh pod yield but also decreased vegetable soybean eating quality. K fertilizer plus the foliar application increased the content of sucrose and fructose but decreased the protein content and increase the fat content. Delaying planting date consistently reduced both fresh pod yield and enzymes activities, and was not beneficial to the editable quality.

Keywords: sucrose, raffinose, protein, enzymes, agronomic practices.