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Proposed descriptors for the evaluation of skin color, flesh firmness and juiciness, and sugar composition in Japanese persimmon breeding
- Asakuma, Hideaki, Shiraishi, Mikio
- Euphytica 2017 v.213 no.3 pp. 69
- Diospyros kaki, analysis of variance, carbohydrate composition, color, cultivars, firmness, genotype, juiciness, palatability, persimmons, plant breeding, pollination, sucrose, sweetness, trees
- Descriptors to evaluate fruit skin color, flesh firmness, flesh juiciness, and sugar composition using pollination constant non-astringent (PCNA)-type cultivars and selections of Japanese persimmon were proposed. A highly positive correlation was observed between the hue angle and color chart, and the skin color was classified as yellowish, hue angle ≥60°; orangish, hue angle between 51° and 59°; and reddish, hue angle ≤50°. Flesh firmness varied from 1.2 to 2.4 kg, and was classified as firm, ≥2.0 kg; medium, 1.4–1.9 kg; and soft, ≤1.3 kg. Flesh juiciness ranged from 0.18 to 0.39 mL g⁻¹ FW, and was classified into very juicy, ≥0.30 mL g⁻¹ FW; juicy, 0.21–0.29 mL g⁻¹ FW; and slightly juicy, ≤0.20 mL g⁻¹ FW. The analysis of variance for the flesh firmness, flesh juiciness, and sugar composition showed that the effect of genotype was large, while the effects of year, genotype × year interaction, among trees within genotype, and tree × year interaction were small or negligible. High varietal differences in sugar composition were found, ranging from 11.6 to 61.5% of the sucrose percentage. Furthermore, the sucrose to hexose (SH) ratio would be a useful descriptor for improving the palatability, especially sweetness, of PCNA-type persimmon fruits. The SH ratio ranged from 0.14 to 1.57, and was classified as very sweet, ≥1.00; sweet, 0.31–0.99; and less sweet, ≤0.30.