Chemical thinning of plum varieties
1996
Harangozo, T. (Hungarian Fruit Federation, Budapest (Hungary)) | Szabo, Z. (Pannon Univ. of Agric. Sci., Keszthely (Hungary)) | David, M. (Univ. of Hort. and Food Industry, Budapest (Hungary))
Chemical fruit thinning experiments were carried out at Soskut and Kecskemet (Hungary) from 1989 to 1991. Results are summarized in 5 points: 1. NAA (a naphthyl acetic acid), ethephon (2-chloroethyl phosphoric acid) and paclobutrazol are available for fruit thinning, but the varieties (Stanley, Bluefre, Cacanska rodna) had different reaction to increased concentrations. 2. Fruit weight and thinning percents were recorded annually. Avarage fruit weight increased, but the yield of treated trees decreased compared to the controls. 3. Impact of the orchard sites on thinning was also studied. The same thinning treatments were carried out in Soskut and Kecskemet (Hungary). There was 10 percent difference in the thinning effect when figures were related to the controls. 4. Timing of the applications was also studied. In 1990 there was 5 difference between the applications performed 5 and 8 weeks APF (after petal fall). 5. Concentration of the thinning chemicals (NAA, ethephon, paclobutrazol) were determined according to its effect on fruit set. The later they were applied the higher was the necessary concentration. 6. Acid and soluble solid content of fruits were measured in all varieties. Chemicals had no significant effect on the fruit quality parameters
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