Cultivar variations in sugar contents in the fig syconia, their parts and nodal positions

Abstract

Variations in sugar contents in fig syconia, their parts and nodal positions among cultivars were investigated. 1. Glucose and fructose are the major sugars, whereas sucrose is a minor one in the fruitlets of the second crop in 10 Common figs (Ficus carica L. vat. hortensis Shinn) and of the first crop in 3 San Pedro-type figs (F. carica L. vat, intermedia Shinn) and 1 Common fig. However, among cultivars, sucrose content in the second and first crop syconia fluctuated more than did those of glucose and fructose. 2. In the fruitlets and fleshy peduncular tissue of the second crop syconia of 'Masui Dauphine' and 'Houraishi', common figs, glucose and fructose contents increased rapidly two weeks before harvest; while the percentages of glucose to total sugar contents decreased, those of fructose increased. The differences in proportions of sugar constituents between the fruitlets and fleshy peduncles were not significant at harvest. 3. The fresh weights of the fruitlets and fleshy peduncles of the second crop 'Masui Dauphine' and 'Houraishi' increase about 4 times between the 70th day after bearing and harvest; the peduncular tissue of 'Masui Dauphine' and the fruitlets of 'Houraishi' enlarged significantly during this period compared with the rest of the syconium. The total sugar contents, on fresh weight basis, of the fruitlets and peduncles increased during the ripening stage, especially in 'Houraishi'. Sugar concentrations in the fruitlets were higher than that of the peduncular tissue at harvest. 4. In the fruitlets of the second crop 'Masui Dauphine' and 'Houraishi', the percentages of sucrose to total sugar contents increased progressively with nodal position; this increase is attributed to periods of low autumnal temperature which occured during late harvest.