Effects of low chill supplying on dormancy dynamics of different apple tree cultivars
The experiment was developed in an orchard located at Arroio do Padre, Brazil. The objective of this research was to evaluate the behaviour of different apple tree cultivars grown under subtropical climate. Three cultivars of apple trees with varying chilling requirements were used: Eva (low-chilling), Castel Gala (medium-chilling) and Mollies Delicious (high-chilling). Two biological tests were performed to determine the dormancy dynamics; the Tabuencas test, which determines the water content inside buds and the single-node cutting test, to estimate the dormancy depth. To perform these tests, long shoots bearing vegetative buds and short shoots bearing floral buds from each cultivar were regularly collected during the winter period of 2015. Dormant state in vegetative buds was evaluated by the single-node cutting test and in floral buds by the Tabuencas test. The dormancy process is affected by the lack of cold temperatures. High temperature variation during the rest period did not allow the cultivars to reach a deep stage of dormancy, making dormancy phases difficult to differentiate. Results demonstrate that all cultivars presented superficial dormancy (ecodormancy) during the whole winter, and the bud bursting capacity is attached to favourable growth conditions. This research may be helpful for future achievements in the area of tree phenology under atypical conditions and could be expanded to screen more cultivars.
de Albuquerque, I., Mello-Farias, P.C., Yamamoto, R.R., Soares Chaves, A.L. and Herter, F.G. (2019). Effects of low chill supplying on dormancy dynamics of different apple tree cultivars. Acta Hortic. 1242, 645-650
Malus domestica, water content, endodormancy, bud weight, chilling requirement