ISHS Acta Horticulturae 463: VIII International Symposium on Plant Bioregulation in Fruit Production
POST-BLOOM THINNING WITH 6-BENZYLADENINE |
| Authors: | S.A. Bound, K.M. Jones, M.J. Oakford |
| Keywords: | apple, chemical thinning, cytokinin |
| Abstract:
Crop regulation and subsequent effects on fruit size, fruit quality and regular cropping is dependent on having a predictable thinning program in place. Carbaryl, the only chemical registered as a post bloom thinner in Australia, is also a persistent pesticide which is toxic to bees and beneficial species important in integrated pest management programs. Although carbaryl is the standard thinning treatment in many countries, in Australia it is not an effective or consistent thinner on many apple cultivars. It is also extremely weather dependent, and if applied under unfavourable conditions can lead to fruit damage. Increasing environmental awareness of the need to reduce pesticide use and avoid persistent chemicals has led to a search for substitutes. Trials on the difficult to thin cultivar red ‘Fuji’ with the synthetic cytokinin 6-benzyladenine (BA) showed that BA was a likely candidate as a post-bloom thinner at around 20 days after full bloom. Further work combining BA in a program with the blossom thinner ethephon resulted in the development of a 3-dimensional surface (model) which was used to determine the optimal concentration and time of application for BA on red 'Fuji'. Later work with red 'Delicious' and 'Golden Delicious' developed successful programs for BA as a post-bloom thinner of these two cultivars. While BA can be applied over a reasonable time period its efficacy is dependent on temperature. BA increased the number of cells in the fruit, thus increasing fruit size independent of the thinning effect. Fruit firmness and soluble solids content are also increased by BA. This work has resulted in registration of BA in Australia under the trade name CyLex. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
