Abstract
Strangulation with a thin wire of the main branch of 3-year-old‘Tosa Buntan’pummelo (Citrus grandis (L.) OSBECK) trees grown in a plastic house was perfomed in mid-November 1990. The duration of the strangulation treatments was 1, 3 and 20 months. Although the numbers of inflorescences, flower buds and flowers opened were much larger in the treated trees than in the control trees, the differences among the treatments were not significant at 5% level in 1991. The number of sexual organs was also larger in the 20-month treatment than in the other treatments in 1992. The percentage of fruit sets was lower in the treated trees than in the control trees, without any significant differences at 5% level among the strangulation treatments in 1991. The girdles after the release of the wire rings in the 1 and 3-month treatments were healed due to the rapid enlargement of the branch girth by late May, while the enlargement rate of the branch girth in the 20-month treatment was lower than that in the other treatments. The contents of sugar and total carbohydrates and C-N ratio in the spring leaves sampled in late August increased with the increase of the duration of the treatment. Fruit growth in the 20-month treatment was slightly depressed in the late growing season. Fruits in the 20-month treatment showed, a lower value for weight, longer shape, more rapid rind degreening and higher content of total soluble solids (TSS) in juice than those in the other treatments.