Bud break promoters following different chilling hour accumulation of 'Hosui' pear

E.S. Abreu, M. Dini, B. Carra, P.M. Marchi, F.G. Herter, P.C. Mello-Farias
Pear is a temperate crop, which grows in mild winter regions, and may present several development anomalies, which can negatively affect yield and fruit quality. To overcome these obstacles and achieve economically satisfactory yields, the use of bud break promoters has shown promising results. The most used promoters are hydrogen cyanamide (HC), mineral oil (MO) and Erger®. The present study aimed to evaluate the effectiveness of HC, MO and Erger® following different chilling hour accumulation on bud break of 'Hosui' pear. 'Hosui' pear shoots were collected with 103 chill hours (CH) and conditioned in cold storage at 4±1°C for 0, 6, 12, 18, 24 and 30 days. For each date, shoots were cut as single bud cuttings, where the following treatments were applied in four replications of ten cuttings: control (water), HC 1%, MO 5%, Erger® 3% + calcium nitrate 3%, and HC 0.5% + OM 3%. After these, they were forced in a growth chamber until bud break, which was assessed every two days to estimate the bud break percentage and average bud break time. Bud break percentage showed no difference between treatments when submitted to 0 and 6 days (247 CH) of cold storage. After 12 days (391 CH), HC and HC + MO increase bud break percentage compared to the control. Those exposed to 18 days (535 CH) and treated with HC and HC + MO showed no significant difference in the bud break percentage compared to the control, whereas Erger® and MO significantly decreased the bud break percentage compared to other treatments. The average bud break time of HC treated cuttings was advanced the most and control delayed the most. When cuttings were subjected to low chilling hour accumulation, HC and HC + MO were more effective in bud break compared to Erger® and the control, while with higher chilling hour accumulation, the bud break promoters were dispensable.
Abreu, E.S., Dini, M., Carra, B., Marchi, P.M., Herter, F.G. and Mello-Farias, P.C. (2021). Bud break promoters following different chilling hour accumulation of 'Hosui' pear. Acta Hortic. 1303, 299-304
DOI: 10.17660/ActaHortic.2021.1303.42
Pyrus pyrifolia Nakai, dormancy, hydrogen cyanamide, mild winter conditions, Erger®, mineral oil

Acta Horticulturae