Abstract: The phenology and fruit quality data from 11 Fuji apple orchards of the main production counties in Shaanxi province were collected between 2016 and 2017. Multiple?stepwise?regression and weighted sum method were used to establish the climate quality index and the climate quality certification model，which could provide scientific supports for the quality assessments of Fuji apple in Shaanxi. Results indicated that the average fruit weight, firmness, soluble solid and titratable acid content were all significantly positive related with the precipitation during the fruit expanding stage, the daily temperature ranges during the young fruit period, as well as the mean minimum temperature and precipitation during the ripe period (P<0.05). However, significant negative correlation was found between fruit horizontal?diameterand the average temperature during the growing season (P<0.05). In order to yield better Fuji apples, the relevant climatic conditions listed below should be satisfied, such asthe daily temperature ranges during the young fruit period larger than 7.9℃, the precipitation during the fruit expanding stage≥134.9mm, the mean minimum temperatureand precipitation during the ripe period≥6.1℃ and ≤79mm, respectively, as well as the average temperature during the growing season≤17.5℃. The?prediction accuracy of CQEI was 86.7%, which implied that the quality evaluation index in this study could be used to assess the quality of Fuji apples in Shaanxi.

Key words: Red Fuji apple, Phenological phase, Climate quality, Climate quality evaluation index