INRA, University Bordeaux, UMR Biologie du Fruit et Pathologie, Villenave d'Ornon, France.
Department of Plant Developmental Biology, Max Planck Institute for Plant Breeding Research, 50829, Cologne, Germany.
Int J Biometeorol. 2019 Feb;63(2):183-192. doi: 10.1007/s00484-018-1649-5. Epub 2018 Nov 20.
Evaluation of chilling requirements of cultivars of temperate fruit trees provides key information to assess regional suitability, according to winter chill, for both industry expansion and ongoing profitability as climate change progresses. Traditional methods for calculating chilling requirements use climate-controlled chambers and define chilling requirements (CR) using a fixed bud burst percentage, usually close to 50% (CR-50%). However, this CR-50% definition may estimate chilling requirements that lead to flowering percentages that are lower than required for orchards to be commercially viable. We used sweet cherry to analyse the traditional method for calculating chilling requirements (CR-50%) and compared the results with a more restrictive method, where the chilling requirement was defined by a 90% bud break level (CR-90%). For sweet cherry, this higher requirement of flowering success (90% as opposed to 50%) better represents grower production needs as a greater number of flowers leads to greater potential yield. To investigate the future risk of insufficient chill based on alternate calculations of the chilling requirement, climate projections of winter chill suitability across Europe were calculated using CR-50% and CR-90%. Regional suitability across the landscape was highly dependent on the method used to define chilling requirements, and differences were found for both cold and mild winter areas. Our results suggest that bud break percentage levels used in the assessment of chilling requirements for sweet cherry influence production risks of current and future production areas. The use of traditional methods to determine chilling requirements can result in an underestimation of productivity chilling requirements for tree crops like sweet cherry which rely on a high conversion of flowers to mature fruit to obtain profitable yields. This underestimation may have negative consequences for the fruit industry as climate change advances with climate risk underestimated.
评估温带果树品种的需冷量，根据冬季需冷量，为行业扩张和气候变化带来的持续盈利能力提供了关键信息，以评估区域适宜性。传统的计算需冷量的方法使用气候控制室，并使用固定的萌芽率（通常接近 50%）来定义需冷量（CR-50%）。然而，这种 CR-50%的定义可能会估计出导致开花率低于果园商业可行性所需的需冷量。我们使用甜樱桃来分析传统的计算需冷量（CR-50%）的方法，并将结果与更严格的方法进行了比较，其中将需冷量定义为 90%萌芽水平（CR-90%）。对于甜樱桃，这种更高的开花成功率（90%而不是 50%）更好地代表了种植者的生产需求，因为更多的花朵会带来更大的潜在产量。为了研究基于不同需冷量计算的未来冬季需冷量不足的风险，我们使用 CR-50%和 CR-90%计算了欧洲冬季需冷量适宜性的气候预测。景观上的区域适宜性高度依赖于定义需冷量的方法，在寒冷和温和的冬季地区都发现了差异。我们的研究结果表明，在评估甜樱桃需冷量时，所使用的萌芽率水平会影响当前和未来生产地区的生产风险。传统方法来确定需冷量可能会导致对甜樱桃等依赖于高花朵转化为成熟果实以获得盈利产量的树木作物的生产力需冷量的低估。随着气候变化的推进，气候风险被低估，这种低估可能会对水果产业产生负面影响。
