Inheritance of taste characters and fruit size and number in a diploid Actinidia chinensis (kiwifruit) population

We investigated the variability and inheritance of taste components and fruit size and number in a seedling population of diploid Actinidia chinensis Planch. We found significant variation in all characters measured. Narrow-sense heritability estimates were high for vitamin C content, titratable acidity (TA), soluble solids content (SSC), fruit weight and dry matter content (DM), but low for glucose content, quinic acid content, and fruit number per vine. The genetic correlations between sugars (except myo-inositol), acids (except quinic acid), TA, vitamin C content, SSC and DM tended to be positive and moderate to high. However, correlations between these characters and fruit weight tended to be negative and moderate to high. The standardised coefficients (beta) of multiple regression showed that SSC was highly dependent on the levels of fructose content, sucrose content and TA. Estimates of relative selection efficiencies (E) suggested that selection using SSC could be an efficient and convenient alternative to direct selection for improvement of sugar levels in kiwifruit. However, selection strategies based on SSC need to take account of its moderate negative correlation with fruit weight. Male and female parents useful for improving acid and sugar composition and fruit size were identified. One family was outstanding, as it combined large fruit size with high levels of SSC and DM.