Relationship Between Shoot Growth and Fruit Production of 'Masui Dauphine' and 'Houraishi' Fig Trees at Various Plant Densities

摘要

This study aimed to determine the optimal shoot vigor to produce large fruit and high yields of the fig (Ficus carica L.) cultivars 'Masui Dauphine' and 'Houraishr. Fruit production of the two cultivars was compared for seven years on shoots of various vigor induced by different plant densities: 20, 61, 400, 667, and 2000 trees per 1000 m(2), and all shoots occupied equal-sized basal areas (0.5 m(2) for each shoot). Individual shoot weight (shoot weight) and number of superfluous shoots were greater in the trees grown at higher plant density. The greater shoot growth under higher plant density was consistent for seven years for 'Mitsui Dauphine', but such an increase was suppressed after the third year for 'Houraishr' trees. The relationship between fruit production and shoot weight showed that fruit maturation did not last until late autumn and the number of fruits harvested (fruit number) declined on the shoots smaller than approximately 0.15 kg on 'Mitsui Dauphine' trees and by approximately 0.8 kg in 'Hon raishi' trees. In early autumn, however, the fruit number was larger on the smaller shoots than that on the larger shoots in `Houraishf trees. The annual means of individual fruit weight (fruit weight) were negatively correlated with shoot weight from the third to seventh years for 'Houraishi' trees, but only for the fifth year for 'Mitsui Dauphine' trees. The fruit ield per shoot (fruit yield) was positively correlated with shoot weight based on the fruit number. However, the correlation coefficients between fruit yield and shoot weight were lower in 'Houraishr trees because the fruit weight was negatively correlated with the shoot weight. Relatively large shoots in a compact tree area will be useful for 'Mitsui Dauphine' figs to avoid fruit yield decline. Conversely, smaller shoots in a large tree area will be useful for 'Houraishr' figs to produce more and larger fruit in early season of harvesting.