ENDODORMANCY OF APPLE AND PEAR BUDS IN A REGION OF LOW CHILL OCCURRENCE IN BRAZIL

R.I.N. Carvalho, G.P. Pereira , A.E. Prado , L.A. Biasi , F. Zanette
The objective of this work was to evaluate the endodormancy of ‘Imperial Gala’ apple and ‘Hosui’ pear buds in a region of low chill occurrence in Brazil. Stems were collected weekly during autumn-winter 2009. Extra sets of stems were collected during the last week of winter and maintained at 4-7°C for 1440 h. The evaluation of dormancy was performed by using the single-node cutting biological test, under controlled conditions (25°C and 16 h photoperiod). Chilling hours (CH) and chilling units (CU) of the region were estimated. The two species were analyzed individually. A completely randomized experimental design with nine treatments, four replications, and ten cuttings per plot, was used. Cuttings were evaluated for 40 days. Endo-dormancy in ‘Imperial Gala’ apple buds presented a variation from early June to end of July, with the higher average bud break time (ABT) (18.4 days) and the lower velocity of bud burst (VB) (0.56 buds day-1) in July 15. Chilling in the region was not enough for natural bud break, because the buds that received additional chilling presented the shorter ABT (8.9 days) and higher VB (1.14 buds day-1). Endodormancy in ‘Hosui’ pear buds exhibited a variation from June 10 to July 22 (ABT of 25.3 to 34.6 days), and the bud break only occurred with additional chilling (ABT of 7.2 days and VB of 1.49 buds day-1). The final percentage of apple bud burst was not influenced by the endodormancy variation, but the pear bud burst was 100% only with additional chilling.
Carvalho, R.I.N., Pereira , G.P., Prado , A.E., Biasi , L.A. and Zanette , F. (2012). ENDODORMANCY OF APPLE AND PEAR BUDS IN A REGION OF LOW CHILL OCCURRENCE IN BRAZIL . Acta Hortic. 932, 447-451
DOI: 10.17660/ActaHortic.2012.932.65
https://doi.org/10.17660/ActaHortic.2012.932.65
Malus domestica, Pyrus pyrifolia, budburst, chilling hours, dormancy
English

Acta Horticulturae