ABSTRACT In the context of global warming, mild winter temperatures could compromise the fulfilment of the chilling requirement (CR) for overcoming flower bud endodormancy, impacting on the yields of perennial species such as apricot (Prunus armeniaca L.). Long-term and site-specific data on air temperatures allowed us to explore the influence of yearly chill accumulation on the endodormancy release of flower buds and blooming responses of two apricot cultivars (‘San Castrese’ and ‘Orange Red’) selected as models for their different characteristics such as geographical origin, CRs of flower buds, blooming time, and fruiting regularity. The CR for breaking flower bud endodormancy was determined by the ‘forcing test’, and the accumulation of chill temperatures was estimated using the Chilling Units (CUs) model. Since the 1990s, milder autumn–winter temperatures and a decline in CUs were recorded. These occurrences had consequences on the endodormancy release, influencing date, and intensity of blooming. ‘San Castrese’, although able to conform to warmer winters, showed the most significant changes in terms of blooming date delay, and reduction in blooming and fruiting intensity. Based on the irregular winter chilling locally verified over several years, serious alterations in apricot floral biology can be predicted.

中文翻译：

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基于长期观察的秋冬季气温对意大利中部杏（Prunus armeniaca L.）内眠释放和开花性能的影响

摘要 在全球变暖的背景下，温和的冬季气温可能会影响克服花芽内休眠的寒冷要求 (CR)，从而影响多年生植物如杏 (Prunus armeniaca L.) 的产量。空气温度的长期和特定地点数据使我们能够探索每年寒冷积累对花蕾内休眠释放和两个杏品种（'San Castrese'和'Orange Red'）的影响，被选为模型它们的地理起源、花蕾的CRs、开花时间和结果规律等不同特征。打破花芽内休眠的 CR 是通过“强制测试”确定的，并且使用冷却单元 (CU) 模型估计冷却温度的积累。自 1990 年代以来，记录到更温和的秋冬季温度和 CU 的下降。这些事件对内眠释放、影响日期和开花强度产生了影响。'San Castrese' 虽然能够适应温暖的冬季，但在开花日期延迟以及开花和结果强度降低方面表现出最显着的变化。根据当地几年来验证的不规则冬季寒冷，可以预测杏花生物学的严重变化。