Genotypic and Environmental Variation in Soybean Seed Cell Wall Polysaccharides

Soybean [Glycine max (L.) Merr.] seed cell wall polysaccharides (CWP) have been characterized, but little is known about their genotypic variation. This information would be beneficial for determining genetic strategies for manipulating CWP content and composition. Seed CWP was determined by the Uppsala total dietary fiber method to quantify monosaccharides of CWP in 14 soybean genotypes from Maturity Groups 00 to I grown at four Minnesota locations. CWP concentration of mature whole seed varied from 158 to 176 g/kg dry matter (DM). Genotypic but not environmental effects were significant for total CWP concentration. For individual monosaccharide concentrations, both genotypic and environmental effects were present. Seed of five genotypes were separated into cotyledon and seed coat for CWP analysis. Genotypic variation for CWP concentration was mostly in cotyledon and not seed coat. Pectin was mostly in cotyledon rather than seed coat with 80.8 and 14.6 g pectin/kg of whole seed DM in cotyledon and seed coat, respectively. Only xylose, glucose, galactose, and uronic acid concentrations were significantly different among genotypes in cotyledon. The correlation between CWP concentration and protein plus oil concentration among the 14 genotypes was r = −0.724, which suggests that an increase in protein plus oil content is associated with a reduction of CWP concentration. The genotypic variation observed suggests that it is possible to breed for reduced CWP. However, genotypic variation for some monosaccharides was limited, suggesting that other methods of genetic manipulation may be more efficient in reducing these monosaccharides.