ISHS Acta Horticulturae 446: VI International Symposium on Vaccinium Culture
RESPONSE OF RABBITEYE BLUEBERRY (VACCINIUM ASHEI READE) TO GIBBERELLIC ACID RATE |
| Authors: | D. Scott NeSmith, G. Krewer |
| Keywords: | growth regulator, fruit set, GA3 |
| Abstract:
Recent observations and research in Georgia has revealed that substantial enhancement of rabbiteye blueberry fruit set and yield can be achieved on a commercial basis with properly timed applications of gibberellic acid (GA3). Using GA3 can be costly; hence, this research was conducted to determine the rate required for the growth regulator to be used effectively by growers. A greenhouse study evaluated GA3 concentrations of 0, 84, 168, and 251 mg/liter applied to potted plants in excess spray volume until drip occurred. An observation in the field in 1994 examined rates of 0, 24, 47, and 94 g GA3/ha applied with an air-blast sprayer to mature bushes in a spray volume of 375 liters/ha. In 1995, field rates were 0, 38, 56, and 75 g GA3/ha applied in a similar spray volume. All applications were made to 'Tifblue' plants at bloom stages 5 to 6. Analysis of fruit set and yield data revealed there was a definite rate response to the growth regulator. We concluded that two applications at a concentration of 150 to 200 mg GA3/liter gave a maximum response of fruit set. This translates into a field application rate of 50 to 70 g GA3/ha applied in 375 liters/ha of spray volume. A collateral wash-off experiment indicated rapid uptake of GA3 the first few hours following application, with residual uptake possible for 2 to 3 days after application. | |
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