Quantitative and Qualitative Changes in Sugar Content of Peach Genotypes [Prunus persica (L.) Batsch.]

Abstract

Fruit of four clingstone peach [Prunus persica (L.) Batsch.] seedling populations, 54 advanced selections, and the cultivars Allgold and Goldilocks were analyzed for sugar content, soluble solids concentration (SSC), and acidity. Sucrose, glucose, fructose, and sorbitol were identified and quantified by high pressure liquid chromatography (HPLC) analysis. Variation was found for all the sugars between the seedling populations. Comparison of the means for the advanced selections with `Goldilocks' indicates that progress has already been made toward selection for a sweeter peach. Glucose, fructose, sorbitol, SSC, and acidity (citric) differed significantly for two harvest years, while sucrose and total sugar concentrations showed no significant yearly variation. A fruit maturity study revealed no significant changes in SSC, percentages of glucose, fructose, and total sugar during ripening on the tree. Acidity and percent sorbitol decreased, while the sugar: acid ratio and percent sucrose increased with increasing maturity. Broad-sense heritability of SSC, acidity, and sugar: acid ratio bad values >0.72, while values for individual sugars and total sugars were much lower. Transgressive segregation for each sugar was found in seedling populations.