Fig. 3. Daily temperature and bud break percentage of ‘Cuiguan' pear in Hangzhou.

Daily mean temperature in Hangzhou (a) and bud-break percentage indicating the dormancy status of ‘Cuiguan’ pear (b) in autumn and winter of 2019. The endodormancy stage is indicated between the vertical dashed red lines. Horizontal dashed red lines indicate temperatures as shown (a) and 50% bud breakage (b). Branches were sampled at the time points shown and were kept in floral foam in forcing conditions for 21 days for measuring the bud-break percentage. When the trees entered endodormancy (start of the period with the lowest bud-break percentage), the daily mean temperature was still ~14 °C, suggesting that the critical temperature to induce endodormancy of ‘Cuiguan’ pear is possibly not lower than 14 °C. When dormancy was released, the temperature was just approximately 7.2 °C, suggesting that the 7.2 °C model might not be suitable for calculating the chilling requirement of ‘Cuiguan’ pear in the Hangzhou area