Determining the Effects of Sulfur Fertility Levels on Edamame Soybean [ Glycine Max ( L. ) Merrill ] Protein Components

Edamame [Glycine max (L.) Merr.] a vegetable type soybean is harvested and consumed before reaching its maturity stage (R6). Its health properties drew attention to U.S. consumers because of its high protein content. Proteins are the major structural component of all cells in the living organisms. They are made of essential and non-essential amino acids which play a big role in growth and development and are source of energy. Proteins act as enzymes, antibodies, and hormones and blood protein. Sulfur (S) is a component of the amino acids cysteine (Cys) and methionine (Met) which are the building blocks for proteins. Little is known about how levels fertility influences protein content in edamame soybean. As result, a solution culture experiment in a protected environment was conducted to evaluate the effect of S fertility concentrations on protein content in edamame. Seeds of the ‘Chiba’ edamame were allowed to germinate under greenhouse conditions at 22 °C day/14 °C night for 15 days and transplanted in nutrient solution culture in the fall of 2016 using a modified Hoagland’s solution containing S treatment concentrations of 4, 8, 16, 32, and 64 mg S L-1 was delivered as magnesium sulfate (MgSO4) and sodium sulfate (Na2SO4). Treatments were arranged in a randomized complete block design with four replications containing five s treatment levels per replication. The solution was changed every 2 weeks after transplanting until plants reached the R6 maturity stage. Plants were harvested approximately 60 days after planting and weighed for fresh biomass (FM) before tissues were dried at 60 °C prior the extractions and protein content analysis. Elemental S concentrations were measured in oven-dried bean tissue using ICP-MS. Manipulating the S fertility concentrations showed no significant difference on bean accumulation of crude protein (P=0.171), Adjusted protein (P=0.171), ADFNDF (P=0.409), ADFDM (P=0.707), aNDf (P=0.271). The results showed that increasing the S concentration from 4 to 64 mg S L-1 in nutrient solution culture did not affect the protein composition in ‘Chiba’ edamame. KEYWORDS: amino acids, ‘Chiba’, ICP, macronutrient, micronutrient