2019 ASHS Annual Conference

Glucose, fructose, and sucrose concentrations contribute greatly to the sweetness and flavors of the foods we eat, including snap beans (Phaseolus vulgaris). Little is known about the patterns of sugar development between the edible pod and seed tissues that make up a snap bean. This study analyzed concentrations of glucose, fructose, and sucrose in 87 accessions of Phaseolus vulgaris from the USDA Core collection using high-performance liquid chromatography. Significant differences in sugar accumulation patterns were observed among the accessions, and between pod and seed tissue types. Overall glucose and fructose concentrations are both highly negatively correlated with sucrose concentrations. The majority of glucose and fructose was concentrated in the pod tissues. Sucrose was generally (but not always) higher in pod tissue than seeds. Seed tissues are composed primarily of sucrose, and therefore overall sucrose levels had a high positive correlation with seed size (percent seed by weight). Overall, genotypes with smallest seeds had the highest total (glucose+ fructose+ sucrose) sugar content, whereas genotypes with the largest seeds had the lowest total sugar content. Although years were significantly different, genotype-by-year interactions were mildly significant only for sucrose content. However, a Spearman rank correlation (r=0.5379) suggests that the ranks were consistent over the years.