ISHS Acta Horticulturae 395: Dormancy and the related Problems of Deciduous Fruit Trees
THE EFFECT OF CONCENTRATIONS AND APPLICATION OF HYDROGEN CYANAMIDE ON KIWIFRUIT DORMANCY BREAKING |
| Authors: | E. Schuck, J.L. Petri |
| Keywords: | Actinidia deliciosa, cv. Hayward, Delayed foliation, Flowering |
| Abstract:
In the south of Brazil, kiwifruit (Actinidia deliciosa) cv. Hayward is not well adapted due to insufficient chilling during dormancy. To improve bud break and yield of mature plants, an experiment was carried out by using different hydrogen cyanamide (H2CN2) concentrations and application times. In 1991–1992, H2CN2 was applied at 5, 3,5 and 2 weeks before natural bud break and at four concentrations (0,5%; 1%; 2% and 3%). In 1992–1993, the product was applied at 5 and 3,5 weeks before natural bud break at three concentrations (0,5%; 1% and 1,5%). Measurements consisted of: percent bud break, flowers/bud ratio and flowers/broken bud ratio, fruits/plant and yield. Bud break was variable among treatments in both years; the best reached 50%. Higher concentrations of hydrogen cyanamide gave the highest percentage of bud break. Plants showed increasing sensitivity to hydrogen cyanamide with decreasing time between application and bud break, mainly with higher concentrations. In 1991–1992, flowers/bud ratio, flowers/broken bud ratio and fruits/plant were significantly higher on plants treated with 0,5 and 1% H2CN2 applied 5 weeks before natural bud break than those with other treatments, and all were different from controls. The best treatments produced 149,3 and 151,7 fruits/plant, respectively, compared to 14,4 fruits/plant for controls. In the second season, 0,5 and 1% H2CN2 applied at second time were the best treatments. They produced 305,5 and 343 fruits/plant compared to 74 fruits/plant for controls. These experiments suggest that for 'Hayward' located in places with high fluctuations of temperature during dormancy, the best responses to hydrogen cyanamide are from 1 to 2%. The application time should be 4 to 5 weeks before natural bud break. | |
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