Use of phenoclimatic models to estimate the chill and heat requirements of four sweet cherry cultivars in Italy

During their dormant period, fruit trees require a certain amount of relatively low temperatures to complete bud differentiation processes and regularly resume growth the following spring. Unsatisfied chilling needs can result in delayed foliation, severe yield and fruit quality losses. There is a need for a method to estimate accurately the chilling requirement of a cultivar. This is especially important in those areas where the potential of chill accumulation in winter is low and for those crops, such as sweet cherry, which generally have a high chilling requirement. Historical temperature records and blooming dates of four sweet cherry cultivars widely cultivated in Italy - 'Burlat', 'Sw…