ISHS Acta Horticulturae 444: III International Symposium on Kiwifruit
THE EFFECT OF HIGH TEMPERATURES ON BREAKING BUD DORMANCY IN KIWIFRUIT (ACTINIDIA DELICIOSA) |
| Authors: | I.C. Porlingis, I.N. Therios |
| Abstract:
Potted plants of kiwifruit (cvs Bruno and Hayward) were kept during the fall in a heated greenhouse. In December they were defoliated and placed in growth cabinets. Plants continuously maintained at 17° C remained dormant during the whole experimental period (100 days). In plants exposed to 30° C or 35° C for 5, 10, 15, 20, or 30 days and subsequently maintained at 17 °C the observed bud break percentage was increasing both by raising the temperature from 30 ° C to 35 ° C or by extending its duration. These results were verified in another experiment in which the temperature of 25 ° C was included. Unchilled plants were maintained in growth cabinets with 17, 25, 30 or 35 ° C and after bud break were transferred to 17 ° C. Control plants (17 ° C) remained dormant while heat treated plants started to grow. The number of days required for 50% bud break was inversely related with the temperature level. The high temperature is effective only after previous defoliation of plants. Continuous exposure to 30 ° C was more effective than when 30°C alternated with 17 ° C of equal duration (2 or 8 days cycles). When the plants were subjected to winter cold and their chilling requirements were completely satisfied, the percentages as well as the rates of bud break at 17, 25, 30 or 35 ° C were almost equal. | |
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