On the Varietal Differences and Heritabilities for Seed Protein Percentage and Sulfur-Containing Amino Acid Contents in Cultivated Soybeans, Glycine max Merrill.

Abstract

For the purpose of investigation of varietal differences for sulfur-containing amino acid contents in soybean seed protein, and of studying their genetic proprties, 55 varieties grown at Faculty of Agriculture, Iwate University, Morioka, in 1968 and 1969, were used for the determinations of protein percentage by macro-Kjeldahl method (N×6. 25) and the analyses of sulfur-containing amino acid contents by micro-bioassay. The principal results obtained were as follows : 1. The variation among the varieties ranged from 34.8 to 49.1% in protein, frorm 0.67 to 0.96g/16gN in methionine content, from 0.62 to l.22g/16gN in cystine conterit, and from 1.29 to 2.15g/16gN in total sulfur-containing amino acid content. The coefficients of variation (C.V.) were 6.2, 7.2, 14.2, 10.O% in the above four characters, respectively. The extent of varietal differences for sulfur-con-taining arnino acid contents was considered to be equal to or more than for protein percentage. 2. The heritabilities for protein percentage, me-thionine, cystine and total sulfur-containing amino acid contents were 58.8, 55.1, 66.8 and 66.6%, respectively. Sulfur-containing amino acid contents were thought to have almost equal or higher herita-bility values, compared with protein percentage. 3. The varieties, Kosodefuri, Gokuwase-edamame, Gokuwase-hayabusa, Sangowasedaizu and Laredo showed the highest sulfur-containing amino acid contents, which were regarded as of much use as hybridization materials. The varieties Okute-kuro-daizu, and Tairamame were interesting as materials for the studies on soybean protein quality.