ISHS Acta Horticulturae 444: III International Symposium on Kiwifruit
EFFECT OF LOW TEMPERATURES AND THEIR ALTERNATION WITH HIGHER ONES ON BREAKING BUD DORMANCY OF ACTINIDIA DELICIOSA (CVS. HAYWARD AND BRUNO) |
| Authors: | I.N. Therios, I.C. Porlingis |
| Abstract:
Two - year old self rooted plants of Actinidia deliciosa were used (Hayward and Bruno). Three experiments were conducted. In the first two the plants were exposed continuously to 4°C, 7°C, 10°C, 13°C or 17°C for 250, 500, 750 and 1000 hours. In the 3 rd experiment the effect of 500 hours exposure to constant 7, 13, 17 or 25°C and also the effect of 4°C or 7°C alternated with equal periods of 13, 17 or 25°C were evaluated on bud breaking. The results indicated that a constant temperature of 4°C contributed more to budbreaking than any other of the tested constant temperatures. Exposure to 4°C for 500 hours was adequate to reach the maximum percentage of budbreak, while 750–1000 hours required at 7°C and 10°C. Exposure to constant temperature of 17°C had a zero contribution to dormancy - breaking while continuous exposure to 13°C had very small effectiveness for rest completion. However, when 13°C alternated with 7°C of equal duration (1 or 5 days) a synergistic effect was apparent. On the contrary, alternation of 7°C with 17° or 25°C showed that these two temperatures were antagonistic to 7°C. | |
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