Changes in Sugar Concentrations of Seed and Pod Tissue During Development in Snap and Dry Beans (Phaseolus vulgaris L.)

Abstract

Sugars, including glucose, fructose, and sucrose, contribute significantly to the flavor and consumer acceptance of snap beans (Phaseolus vulgaris L.). Sugar accumulation and changes in sugar profiles during snap bean development contribute to overall assessments of quality for breeding lines and cultivars. Developing fruit from a diverse group of four snap bean cultivars containing Andean germplasm and one Mesoamerican dry bean cultivar were sampled at 5-day intervals from 10 to 30 days after flowering over 2 years. Glucose, fructose, and sucrose in pod and seed tissue was quantified using high-performance liquid chromatography. Percent seed mass relative to pod mass increased with days after flowering, but the rate of increase was heterogeneous among cultivars. Significant differences in sugar accumulation patterns of mono- and disaccharides were observed with time of development and between pods and seeds. Glucose and fructose decreased rapidly in pods and seeds with time after flowering. In contrast, sucrose concentration increased in pod tissue but remained constant in seeds of the snap bean cultivars with time after flowering. The patterns of changes in pod and seed sugar concentrations with time after flowering were similar among all snap bean cultivars. In contrast to the snap beans, seed sucrose increased with time after flowering in the Mesoamerican dry bean cultivar Puebla 152. No year by day after flowering interactions were observed for sugar accumulation patterns or sugar concentrations. Younger snap beans had the highest sweetness index based on observed sugar concentrations, percent seed mass, and perception of relative sweetness by the human palate. Although mean sweetness varied between cultivars, the rate of decrease in sweetness with time was the same for all five cultivars. These findings indicate that variation for sweetness exists in snap beans and can be exploited by breeding to develop cultivars with a potentially more desirable, sweet flavor.

Genome-Wide Association Study to Identify Possible Candidate Genes of Snap Bean Leaf and Pod Color

“…After flowering, the glucose and fructose fraction in pods decreases while sucrose content increases. Similarly, glucose and fructose content in seeds decreased but sucrose content did not change [68]. Phvul.002G300900 at 46,900,118 bp (Pv5-593.02G293900 at 48,119,141-48,156,962 bp), Phvul.004G017400 at 2,047,768 bp, and Phvul.009G134300 at 20,332,723-20,375,268 bp (Pv5-593.09G136600 at 22,054,215-22,086,165 bp) for C* and b* pod exterior, Phvul.006G210800 at 30,376,064 bp for C* pod exterior, Phvul.006G000600 at 281,553 bp for C* pod interior, and Phvul.008G007600 at 706,796-706,932 bp for H • pod exterior was found in our study (Table 6).…”