Bud break promoters following different chilling hour accumulation of ‘Hosui’ pear

Crop Load Management in Nashi Pear—A Review

“…In Brazil, Faoro and Nakasu [25] noted that application of HC and MO is required to ensure adequate bud break in 'Hosui, 'Kosui' and 'Nijisseiki', while Abreu et al [26] reported that HC and HC+MO were more effective than Erger ® in promoting bud break of 'Hosui'. In studies evaluating the effect of vegetable (sunflower) and mineral oils on bud break, yield and enzymatic activity in the cultivar 'Hosui', Botelho et al [27] found that treatment with 4% MO plus 2% VO was as effective as the standard HC treatment in releasing bud dormancy.…”

“…According to Honjo et al [29], 'Kosui' requires around 800 chill hours to break endodormancy, while other cultivars require more than 1600 h. Faoro and Nakasu [25] noted that 'Kosui' is well-adapted to warmer areas in Brazil where the chill accumulation is over 400 h, but the high-chill cultivar 'Nijisseiki' has poor bloom and reduced shoot growth in areas with chill accumulation between 500 and 700 h. This concurs with the findings of Petri and Herter [28] that increasing chilling up to 1440 h resulted in a higher percentage of bud break and flower number per bud for 'Nijisseiki'. Once sufficient chill hours have accumulated, the application of dormancy breakers has no effect [26].…”