Influence of Seeded Fruit on Seedless Fruit Set in Japanese Persimmon cv. Fuyu (Diospyros kaki L. f.).

Abstract

The influence of seeded Japanese persimmon cv. Fuyu (Diospyros kaki L.f.) fruit on the setting of seedless ones achieved by 1)hand-pollination; 2) open-pollination; 3) non-pollination; 4) ringing ofthe bearing shoot; and 5) gibberellin-3 (GA3) application wasinvestigated to clarify the factors affecting seedless fruit set and theinconsistency of GA-treated fruit set.The number of seeds per fruit and the degree to which seedless fruitabscised on the same tree were significantly different among trees.However, a highly significant, positive linear relationship (r=0.77)existed between the two parameters. No abscission of seedless fruits onringed shoots occurred until the girdle region had healed.On non-pollinated trees, seedless fruit set increased as theconcentration of GA3 was increased. However, more seedless fruit droppedfrom pollinated trees than from non-pollinated trees, although seedlessfruits of both plots were treated with the same concentration. Thisinduction of abscission is ascribed to the competition between seedlessfruit and seeded fruit on the same tree. A major factor to fruit set wasthe competition among fruits; the competitive advantage of seeded fruitover parthenocarpic ones is the decisive factor whether or notGA-treated `Fuyu' fruits abscise.