ISHS Acta Horticulturae 754: International Workshop on Advances in Grapevine and Wine Research
GRAPE BUD BURST: THERMAL HEAT REQUIREMENT AND BUD ANTAGONISM |
| Authors: | D. Tomasi, G. Pascarella, P. Sivilotti, M. Gardiman, A. Pitacco |
| Keywords: | Merlot, bud heating, blind buds, growing degree hours, thermal range |
| DOI: | 10.17660/ActaHortic.2007.754.26 |
| Abstract:
Bud burst marks the beginning of seasonal growth and grape production, and it is well known that it is strongly affected by temperature. In grapevine, it has been shown that if canes are trained upward, terminal buds grow shoots first. Bud burst timing is not easily predictable because its relationship with temperature is very complex and because there is strong competition among buds along the cane. Along a single cane, a bud burst hierarchy can be created using artificial tools. An experiment was carried out with the aim of assessing the effect of bud heating on bud burst timing and to evaluate if a bud burst hierarchy could be established in Merlot grapevines. Both curved canes (Sylvoz) and untied canes (Casarsa) were used. In the middle of the cane, where blind buds often occur, two buds were isolated inside a PET (Polyethylen Therphthalate) bottle together with a resistor which enhanced the temperature inside the enclosure. The internal temperature was monitored by using a thermocouple connected with a data-logger; two power levels for bud heating (0.4 W or 0.2 W) were compared and in both cases an anticipation of bud burst was observed when compared to the un-heated control. After budding the two heated buds inhibited the growth of other buds. The inhibition effect was reduced moving away from the heated buds. Analysing the temperatures recorded inside the PET boxes and the external ones, it was possible to obtain some initial information concerning bud burst heat requirement. | |
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