Fraga Helder, Santos João A
Centre for the Research and Technology of Agro-Environmental and Biological Sciences, Universidade de Trás-os-Montes e Alto Douro, Vila Real, Portugal.
Institute for Innovation, Capacity Building and Sustainability of Agri-food Production, Vila Real, Portugal.
Front Plant Sci. 2021 Jun 23;12:689121. doi: 10.3389/fpls.2021.689121. eCollection 2021.
Air temperature plays a major role in the growth cycle of fruit trees. Chilling and forcing are two of the main mechanisms that drive temperate fruit development, namely dormancy and active plant development. Given the strong sensitivity of these crops to air temperature and the foreseeable warming under future climates, it becomes imperative to analyze climate change impacts for fruit trees. The fruit sector in Portugal has risen significantly over the last decades, gaining increasing importance both internally and through exports. The present research assesses the impacts of climate change on the chilling and forcing for economically relevant fruit trees in Portugal, namely apples, oranges, pears, and plums. To assess temperate fruit chilling and forcing conditions, the chilling portions (CP) and growing degree-hours (GDH) were computed over Portugal, for the recent-past (1989-2005) and future (2021-2080) periods, following two anthropogenic radiative forcing scenarios (RCP4.5 and RCP8.5). Future climate data were obtained from four regional-global climate model pairs to account for model uncertainties. Bias-correction methodologies were also applied. A spatial analysis over the main regions with PDO "Protected Denomination of Origin" or PDI "Protected Geographical Indication" of origin of each fruit tree was performed. Future projections show a clear decrease in chilling for all regions and fruit types in Portugal. Nonetheless, given the current chilling values in Portugal and the relative importance of chilling accumulation for each fruit type, these changes are more significant for certain varieties of apples than for other types of fruit. Regarding forcing, the future projections highlight an increase in its values throughout the different fruit tree regions in Portugal, which should lead to earlier phenological timings. These changes may bring limitations to some of the most important Portuguese temperate fruit regions. The planning of suitable adaptation measures against these threats is critical to control the risk of exposure to climate change, thus warranting the future sustainability of the Portuguese fruit sector, which is currently of foremost relevance to the national food security and economy.
气温在果树生长周期中起着重要作用。低温需求和需冷量解除是驱动温带水果发育的两个主要机制，即休眠和植物活跃生长。鉴于这些作物对气温高度敏感以及未来气候下可预见的变暖趋势，分析气候变化对果树的影响变得至关重要。在过去几十年里，葡萄牙的水果产业显著发展，在国内和出口方面都变得越来越重要。本研究评估了气候变化对葡萄牙具有经济价值的果树（即苹果、橙子、梨和李子）的低温需求和需冷量解除的影响。为了评估温带水果的低温需求和需冷量解除条件，在葡萄牙计算了近过去（1989 - 2005年）和未来（2021 - 2080年）期间的低温部分（CP）和生长度日（GDH），遵循两种人为辐射强迫情景（RCP4.5和RCP8.5）。未来气候数据来自四组区域 - 全球气候模型对，以考虑模型不确定性。还应用了偏差校正方法。对每种果树具有“原产地保护名称”（PDO）或“地理标志保护”（PDI）的主要产区进行了空间分析。未来预测表明，葡萄牙所有地区和水果类型的低温需求都将明显下降。尽管如此，鉴于葡萄牙目前的低温值以及每种水果类型低温积累的相对重要性，这些变化对某些苹果品种的影响比对其他水果类型更为显著。关于需冷量解除，未来预测突出显示葡萄牙不同果树产区的需冷量解除值将增加，这将导致物候期提前。这些变化可能给葡萄牙一些最重要的温带水果产区带来限制。针对这些威胁规划合适的适应措施对于控制气候变化暴露风险至关重要，从而确保葡萄牙水果产业的未来可持续性，而该产业目前对国家粮食安全和经济至关重要。
