Effect of Fatty Alcohol and 6-Benzyladenine on Fruit Set and Fruit Quality of ‘Fuji’ Apples

This study was investigated the effect of fatty alcohol (FA) and 6-benzyladenine (6-BA) thinning treatments on the fruit set and fruit quality attributes of ‘Fuji/M.9’ apples. Trees were treated with FA (single, ×500 dilution), FA (double), 6-BA (×1,000 dilution), 6-BA (×500 dilution), FA (single) + 6-BA (×1,000 dilution), FA (double) + 6-BA (×500 dilution), and carbaryl. FA (80.5% a.i.) treatment was applied at 80% blossom of terminal flowers and 60–80% blossom of lateral flowers, and 6-BA (7.4% a.i.) and carbaryl treatments were applied at 8-mm size of central fruit. The total fruit set rate per cluster was observed 61.0% for terminal flowers and 37.3% for lateral flowers in the control but it was decreased to 35.2–50.6% for terminal flowers and 9.7–23.8% for lateral flowers in the thinning treatments, respectively. The rate of central fruit per terminal flower cluster was observed 92.6% in the control but it was 65.2–94.4% in FA and 6-BA treatments. However, the rate of non-fruit set per terminal flower cluster was observed 2.9% in the control but it was increased to 7.5–14.2% in the thinning treatments, and the rate of one fruit set per terminal flower cluster was 14.1% in the control but it was increased to 20.6–33.9% in the thinning treatments. In addition, the rate of non-fruit set per lateral flower cluster was observed 19.6% in the control but it was decreased to 32.2–69.0% in the thinning treatments. The fruit quality attributes were not different in all treatment groups at harvest, except fruit weight. Therefore, our results reveal that FA and 6-BA treatments have the significant effects in reducing the fruit rate in ‘Fuji’ apple.