ISHS Acta Horticulturae 777: IX International Rubus and Ribes Symposium
BREAKING ENDODORMANCY IN RED RASPBERRY WITH NEAR-LETHAL HOT WATER TREATMENT |
| Authors: | P. Palonen, M. Rantanen, L. Lindén |
| Keywords: | budbreak, cold hardiness, rest, Rubus idaeus, stress |
| Abstract:
Insufficient chilling causes poor and uneven bud break in raspberry (Rubus idaeus) plants. This may be a problem in mild winter climates and when raspberries are grown in a greenhouse for year-round production. In many woody plants, endodormancy may be broken by sub-lethal stress. The aim of our study was to examine whether endodormancy in raspberry cultivars can be broken by near-lethal hot water treatment. Field collected canes of four raspberry cultivars were subjected to hot water treatments (35 to 50°C). Time to budbreak in greenhouse forcing was observed. Depending on cultivar, bud dormancy was broken by immersing the canes in 40 or 45°C water for 2 hours. The treatment was most effective during deepest dormancy in October. Hot water treatment (45°C) decreased cv. Ottawa bud cold hardiness (LT50) at different times of the winter by 9.1 to 13.4°C. Plants of raspberry cvs. Ottawa and Glen Ample growing in pots were treated after 0, 240, 480, 720, 960 and 1200 hours of chilling and forced in a greenhouse. Both hot water (45°C) and hydrogen cyanamide enhanced budbreak and lateral growth. For ‘Glen Ample’ hot water and hydrogen cyanamide were equally effective in inducing budbreak, whereas for ‘Ottawa’ hydrogen cyanamide was more effective than hot water during deepest dormancy. However, the number of flowers in hot water treated plants was drastically reduced. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
