EFFECTS OF TEMPERATURE AND POLLINATION ON GROWTH, FLOWERING AND FRUIT-SET OF THE NONASTRINGENT PERSIMMON CULTIVAR FUYU UNDER CONTROLLED TEMPERATURES

A controlled temperature room experiment evaluated the effects of four day/night temperature treatments on flowering, fruit set and growth of 'Fuyu', the most important nonastringent persimmon cultivar grown in Australia. Fruit set of hand-pollinated flowers at 17/12-degrees-C and 22/17-degrees-C was similar and averaged 53.6 and 54.9%, respectively. In contrast, fruit set of hand-pollinated flowers at 27/22-degrees-C and 32/27-degrees-C was significantly reduced by 58 and 77%, respectively. For the three higher temperature treatments, fruit set of non-pollinated flowers was very low (<4.0%) compared with fruit set at 17/12-degrees-C, which averaged 50.2%. The greater fruit set of non-pollinated flowers at 17/12-degrees-C may have been due to a combination of increased flower size and reduced vegatative growth under these conditions. Higher shoot starch concentrations at anthesis were recorded with decreasing temperature, presumably due to reduced growth (17/12-degrees-C, 3.1%; 22/17-degrees-C, 1.9%, 27/22-degrees-C, 0.85%, 32/27-degrees-C, 0.90).