ISHS Acta Horticulturae 394: Plant Bioregulators in Horticulture
FLOWER THINNING EFFECT OF SYNTHETIC AUXINS ON ‘FUJI’ APPLE |
| Authors: | K. Yokota, K. Murashita, S. Takita, M. Nonaka, S. Kato, T. Suyama |
| Keywords: | ‘Fuji’ apple, Thinning, Safty for bees, Synthetic auxins |
| Abstract:
‘Fuji’ apple now accounts for over 50% of the total apple production in Japan. ‘Fuji’ tends to over-set but carbaryl has little effect as a fruit thinner. The fruit thinning is done by hand, requiring a large imput of labour, six synthetic auxins were examined as the flower thinning agents for ‘Fuji’. NAA, dichlorprop, MCPB ethyl, and N-(1,3-dimethyl- 1H-pyrazol-5-yl)-2-[(3, 5, 6-trichloro-2-pyridinyl oxy] acetamide (experimental code name : NSK-905) caused thinning when applied just after full bloom in a 3 year. Ethychlozate and 4-CPA had no effect. Adequate thinning was achieved by spraying NAA at 20ppm and dichlorprop at 45ppm, MCPB ethyl at 30ppm and NSK-905 at 100 to 200 ppm one day after full bloom. In addition to leaf abnormality, severe epinasty was observed in the case of NAA and dichlorprop. Epinasty was also observed from MCPB ethyl but it was slight and did not influence the growth of shoots and fruits. These results indicate that treatment by MCPB ethyl or NSK-905 immediately after full bloom has a possibility to be a new fruit thinning method for ‘Fuji’ apple. | |
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