Article | 02. 2016 Vol. 34, Issue. 1
Effect of Flower and Fruit Thinner on Fruit Set and Fruit Quality of ‘Gamhong’ Apples

Department of Horticultural Science, Kyungpook National University1
Planning and Coordination Division, National Institute of Horticultural and Herbal Science, RDA2
Apple Research Institute, National Institute of Horticultural and Herbal Science, RDA3
Fruit Research Division, National Institute of Horticultural and Herbal Science, RDA4
College of Agriculture and Life Science, Kyungpook National Unviersity5
Department of Herbal Medicine Resource, Kangwon National University, Dogye Campus6
7Department of Horticultural Science, Chonbuk National University7
Department of Horticultural Science, Mokpo National University8

2016.02. 24:31


This study investigated the effects of flower and fruit thinning agents on fruit set and harvested fruit quality attributes in ‘Gamhong’ apples. Lime sulfur, MaxCel (1.9% BA), and Fruitone (3.5% NAA) were applied either at post-bloom or fruitlet stages to mature ‘Gamhong/M.9’ trees. In 2011, the numbers of fruits per cluster in terminal flowers were 1.74, 0.82, and 1.15 for the control, lime sulfur, and Maxcel (applied at 10-mm fruit stage) treatments, respectively. The percentages of single fruit per cluster were 36.0, 47.9, and 48.7% for the control, lime sulfur, and Maxcel (10 mm) treatments, respectively, while the percentages of clusters with three fruits per cluster were 22.9, 1.4, and 5.8%. In lateral flowers, fruit numbers per cluster were 1.20, 0.36, and 0.50 for the control, lime sulfur, and Maxcel (10 mm) treatments, respectively. In 2012, all the thinning treatments showed a positive effect on flower and fruit thinning, compared with the control. Moreover, the treatment with thinning agents did not affect fruit quality. Overall, the results suggest that a single application of flower or fruit thinning agents would be sufficient, rather than the mixed application of thinning agents, based on the observed decrease in fruit setting.

1. BBatjer, L.P. and H.D. Billingsley. 1964. Apple thinning with chemical sprays. Washington State Expt. Sta. Blu. p. 651.  

2. Bound, S.A., K.M. Jones, and M.J. Oakford. 1997. Post-bloom thinning with 6-benzyladenine. Acta Hortic. 463:493-499.  

3. Bound, S.A., K.M. Jones, T.B. Koen, and M.J. Oakford. 1991. The thinning effect of benzyladenine on red 'Fuji' apple trees. J. Hortic. Sci. 66:789-794.  

4. Childers, N.F., J.R. Morris, and G.S. Sibbett. 1995. Modern fruit science. 10th ed. Hortic. Publ., Gainesville, FL, USA.  

5. Chun, I.J., W.W. Zheng, C. Choi, Y.Y. Song, I.K. Kang, and P. Hirst. 2012. Multiple applications of lime sulfur for fruit thinning of 'Fuji' and 'Hongro' apple trees. J. Bio-Environ. Cont. 21:445-451  

6. Dennis, F.G. 2000. The history of fruit thinning. Plant Growth Regul. 31:1-16.  

7. Greene, D.W. and W.R. Autio. 1989. Evaluation of benzyladenine as a chemical thinner on 'McIntosh' apples. J. Am. Soc. Hortic. Sci. 114:68-73.  

8. Greene, D.W., W.R. Autio, J.A. Erf, and Z.Y. Mao. 1992. Mode of action of benzyladenine when used as a chemical thinner on apples. J. Am. Soc. Hortic. Sci. 117:775-779.  

9. Guak, S.H., M. Beulah, N.E. Looney, and L.H. Fuchigami. 2002. Thinning 'Fuji' apple blossoms with synthetic auxins (MCPB-ethyl or NAA) and ethephon with or without postbloom thinning with carbaryl. J. Am. Soc. Hortic. Sci. 127:165-170.  

10. Guak, S., E.J. Kim, J.R. Kook, and D.G. Choi. 2009. MaxCel® as a postbloom thinner for 'Hongro' and 'Fuji' apples. Hortic. Environ. Biotechnol. 50:181-187.  

11. Jang, H.I., J.W. Han, H.J. Lee, K.H. Hong, J.J. Choi, and K.Y. Kim. 1998. Evaluation of lime sulfur mixture as a flower thinner for pear trees (Pyrus pyrifolia cv. Niitaka). J. Kor. Soc. Hort. Sci. 39:423-427.  

12. Kim, E.J. and S. Guak. 2010. Chemical thinning of 'Fuji' apple with ammonium thiosulfate and benzyladenine. Hortic. Environ. Biotechnol. 51:520-524.  

13. Koike, H. and T. Ono. 1998. Optimum crop load for 'Fuji' apples in Japan. Compact Fruit Tree 31:1-9.  

14. Moon, B.W. and C.C. Kim. 1986. Effect of NAA and carbaryl on the fruit thinning in apples (Malus domestica Borkh). J. Korean Soc. Hortic. Sci. 27:239-248.  

15. Kook, J.R., E.J. Kim, D.G. Choi, and S. Guak. 2009. Chemical thinning of 'Hongro' apple with ammonium thiosulfate and MaxCel. Hortic. Environ. Biotechnol. 50:79-83.  

16. Park, M.Y., J.B. Kim, O.H. Ryu, and J.K. Byun. 1998. Thinning of 'Fuji' apple by simazine. J. Kor. Soc. Hort. Sci. 39:30-34.  

17. Robinson, T., A. Lakso, E. Stover, and S. Hoying. 1998. Practical thinning programs for New York. N.Y. State Hortic. Soc. Fruit Quarterly Publ. 1:14-18.  

18. Schröder, M. and F. Bangerth. 2006. The possible 'mode of action' of thinning bioregulators and its possible contribution to the understanding of 'thinning variability' in apples. Acta Hortic. 727:437-443.  

19. Shin, Y.U., J.H. Whang, B.W. Yae, W.C. Kim, J.Y. Moon, and J.H. Kim. 1993. 'Gamhong' a mid-season apple cultivar with high sugar content. Korean J. Hortic. Sci. Technol. 11:250-251.  

20. Stover, E., M. Fargione, R. Risio, X. Yang, and T. Robinson. 2001. Fruit weight, cropload, and return bloom of 'Empire' apple following thinning with 6-benzyladenine and NAA at several physiological stages. HortScience 36:1077-1081.  

21. Wismer, P.T., J.T.A. Proctor, and D.C. Elfving. 1995. Benzyladenine affects cell division and cell size during apple fruit thinning. J. Am. Soc. Hortic. Sci. 120:802-807.  

22. Yoo, J., M.Y. Park, and I.K. Kang. 2014. Effect of fruit thinner on fruit set and quality in 'Hongro' and 'Fuji' apples. Korean J. Hortic. Sci. Technol. 32:577-583.  

23. Yuan, R. and D.W. Greene. 2000. Benzyladenine as a chemical thinner for 'McIntosh' apples. I. Fruit thinning effects and associated relationships with photosynthesis, assimilate translocation, and nonstructural carbohydrates. J. Am. Soc. Hortic. Sci. 125:169-176.