Relationship between surface color and other maturity indices in wild lowbush blueberries

Abstract

The surface color, size, and sugar, titratable acid and anthocyanin contents were measured on samples of various maturities from 72 individual lowbush blueberry clones to determine the relationships between surface color and other ripeness indicators. Among the total 504 berries, the maximum sugar content was approximately 5 times that of the minimum, while the maximum titratable acid and anthocyanin contents were 20 and 11 times those of the minimum contents, respectively. Correlations among variates were generally strongest for samples within clones, and they were weakest among the variate means for the 72 clones. For the total 504 berries, sugar content correlated more strongly with surface color than with berry size, while acid content correlated similarly with surface color and size. Correlations (positive or negative) among berry size and sugar and titratable acid contents did not exceed 0.60. Principal component analysis, which was used to identify groupings of correlated variates, indicated coordinated changes in berry characteristics during ripening, lower sugar and anthocyanin concentrations in large berries, and substantial interclonal variation in wild blueberries. Clonal selections obtained from an experimental trial differed significantly in all the variates measured, while wild clones without a surface bloom were not different from those clones with bloom. Key words: Lowbush blueberry, Vaccinium angustifolium, color, sugar, titratable acid, anthocyanin