Early performance of 'Uenishiwase' persimmon trees on a Y-trellis training system.

Applicability of Y-trellis system to high density persimmon was evaluated for 7 years after planting. Twoyear- old trees of ‘Uenishiwase’ (Diospyros kaki) were planted at a row spacing of 6 m in spring of 1996. Tree spacing within a row was 3 m for modified-leader (ML) and 1.5 m for Y-trellis. It was apparent from 2000 that the increase in trunk cross-sectional area (TCSA) was less in the Y-trellis than in the ML trees. The TCSA of the Y-trellis trees was 19% smaller in 2002 than that of the ML trees. On the other hand, the trees spreaded more in Y-trellis trees. Due to higher planting density and wider tree-spread of the Y-trellis, the cumulative yield per hectare from 1998 to 2002 was 29.4 tons for the Y-trellis trees, a 1.6-fold increase over the ML trees. Light penetration was 10.2% more in the Y-trellis trees. However, there was no consistent difference in fruit characteristics between the two training systems of young trees in this experiment. Despite a higher occurrence of water sprouts in Y-trellis trees on a scaffold limb or land area basis, the results of this study indicated the potential benefits of Y-trellis system for early production of persimmon.