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The oligosaccharides, raffinose and stachyose, have been implicated as causative factors for the flatulence and uncomfortable feeling often experienced after consuming products containing soybean [Glycine max (L.) Merrill] meal. Soybeans are primarily grown for their oil and protein content. Their value might be enhanced, however, if the oil and protein content remained high and the oligosaccharide content were lowered to make them more acceptable for human consumption. Seeds of 60 selected lines from Maturity Groups 00 through IV were analyzed for protein, oil, total sugar, and individual sugar content. The ranges in values for oil, protein, total sugar, sucrose, raffinose, and stachyose were 14.5 to 23.0, 33.1 to 49.2, 5.6 to 10.9, 2.5 to 8.2, 0.1 to 0.9, and 1.4 to 4.1 g per 100 g seed respectively. Simple correlation analysis revealed that total sugar content and oil content in soybean seeds are positively associated, and each was negatively correlated with protein content. Sucrose and raffinose content were positively correlated with oil content, while stachyose content was positively associated with protein. Even though the correlation between certain sugars and oil or protein was statistically significant, considerable variation in total sugar content was not explained by the coefficient of determination (r2).

This study was conducted with the objective of determining the genomic relationship between cultivated soybean (Glycine max) and wild soybean (G. soja) of the subgenus Soja, genus Glycine. Observations on cross-ability rate, hybrid viability, meiotic chromosome pairing, and pollen fertility in F 1 hybrids of G. max × G. soja and reciprocals elucidated that both species hybridized readily and set mature putative hybrid pods, generated vigorous F1 plants, had a majority of sporocytes that showed 18II + 1IV chromosome association at diakinesis and metaphase I, and had a pollen fertility that ranged from 49.2% to 53.3%. A quadrivalent was often associated with the nucleolus, suggesting that one of the chromosomes involved in the interchange is a satellited chromosome. Thus, G. max and G. soja genetic stocks used in this study have been differentiated by a reciprocal translocation. Pachytene analysis of F1 hybrids helped construct chromosome maps based on chromosome length and euchromatin and heterochromatin distribution. Chromosomes were numbered in descending order of 1-20. Pachytene chromosomes in soybean showed heterochromatin distribution on either side of the centromeres. Pachytene analysis revealed small structural differences for chromosomes 6 and 11 which were not detected at diakinesis and metaphase I. This study suggests that G. max and G. soja carry similar genomes and validates the previously assigned genome symbol GG.

The content and heat stability of protease inhibitors of a standard cultivar (Williams 82) and an isoline (L81-4590) lacking the Kunitz trypsin inhibitor (KTI) were measured by using enzyme inhibition and enzyme-linked immunosorbent assays (ELISA). The KTI content of the isoline was less than 0.2% compared to Williams 82, with the exact content depending on the extent of cross-pollination of the soybeans. Steam heating of the isoline flour (121 °C, 20 min) resulted in a near-zero level of trypsin inhibitory activity, while 20% remained in the Williams 82 sample. The raw soy flour prepared from the isoline was nutritionally superior to the raw flour prepared from the standard variety, as measured by PER and pancreatic weights. The increased PER was likely due to the lower level of trypsin inhibitory activity in the isoline. Steam heating the flours for up to 30 min at 121 °C progressively increased the PER for both strains. Screening of several accessions from the USDA Soybean Germplasm Collection showed variation in the content of trypsin inhibitor, sulfur amino acids, and lectins, indicating that further screening studies could lead to the discovery of soybeans which yield flour that is safe and nutritious, with minimal heating.

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The flatus‐producing factor in soybean [Glycine max (L.) Merrill] seed appears to be associated with the sugars raffinose and stachyose. The objective of this investigation was to measure the variability of total sugar and individual sugars in seed from soybean cultivars, the soybean genetic type collection, plant introductions of G. max that were formerly known as G. gracilis Skvortz., and plant introductions of G. soja Sieb. and Zucc. Among the cultivars, ‘Bansei’ had the highest total sugar, sucrose, and stachyose contents—16.6, 10.2, and 3.8 g/100 g seed, respectively. Seed of ‘Sioux’ had the lowest total sugar and sucrose contents—6.2 and 3.0 g/100 g seed. Seed of ‘Chippewa’ and ‘Norsoy’ had the highest and lowest fructose contents—2.1 and 0.4 g/100 g seed, respectively. Raffinose content was highest in seed of ‘Cayuga’ and lowest in ‘Hidatsa’ and Sioux. Strains T‐223 and T‐218 in the genetic type collection had very high stachyose contents—5.8 and 4.8 g/100 g seed. In seed of G. soja PI 203.246, the stachyose content was only 0.6 g/100 g seed. The extent of variability detected for total sugar and individual sugar content offers opportunities for modification of the sugar components in soybeans.

Soybean [Glycine max (L.) Merrill] seds from reciprocal crosses of ‘Amsoy 71’ and P.I. 157440, reciprocal crosses of P.I. 196172 and P.I. 157440, and the cross P.I. 157440 ✕ ‘Jefferson’ were analyzed using polyacrylamide gel electrophoresis to study the inheritance of the absence of the Kunitz trypsin inhibitor (SBTI‐A2). Amsoy 71 has the SBTI‐A2, at Rf 0.79 (Tia), Jefferson at Rf 0.75 (Tib), P.I. 196172 at Rf 0.83 (Tic), and P.I. 157440 lacks the SBTI‐A2, band. The F2 and F3 data establish that the absence of the SBTI‐A2, band is inherited as a recessive to the codominant alleles Tia, Tib, and Tic. The allele for absence of the SBTI‐A2 band is designated ti. The homozygous recessive condition (ti ti) results in the lack of SBTI‐A2. The lack of the SBTI‐A2, protein was confirmed using spectrophometric assay procedures.

Seed protein electrophoresis is increasingly being utilized as an additional approach for species identification and as a useful tool for tracing back the evolution of various groups of plants. This paper summarizes the main features of the seed protein profile - stability, uniformity and additive nature. In addition, the significance of this approach for resolving specific taxonomic and evolutionary problems is pointed out.