Abstract:

This study analyzed soil properties，climate conditions，and fruit quality of 87 Fuji apple orchards across 14 counties in Shandong Province from 2019 to 2021，and the differences between environmental factors and fruit quality were compared among counties. Correlation analysis and redundancy analysis（RDA）were used to screen the main environmental factors affecting fruit quality. The results showed that the average single fruit weight was 262.22 g，more than 60% of the orchards had single fruit weight above 250 g and less than 5% of the orchards had single fruit weight below 200 g. The fruit hardness was concentrated in the range from 6.5 to 7.5 kg · cm^-2. Fruit firmness mainly ranged between 6.5-7.5 kg · cm^-2. The average soluble solids content across counties was 14.45%，showing low variation. The content of titrable acid in Wendeng was the highest（0.32%），while the content in other areas was below 0.30%. Mengyin solid acid ratio was the highest，69.71% higher than the lowest Wenden，with nosignificant differences among other regions. The average pH of the orchard soil was 5.64，indicating an overall acidic nature. There were significant variations in nutrient content across different orchards，particularly in organic matter，available phosphorus，and available potassium，with coefficients of variation exceeding 50%. Correlation analysis showed that soil pH was negatively correlated with fruit quality indexes except titrable acid. Soil organic matter was positively correlated with solid-acid ratio，sucrose and sweetness value，and negatively correlated with titrable acid. Total nitrogen，available phosphorus，and available potassium negatively affected flavor components like sugar-acid ratio and soluble solids. Both average temperature and average temperature difference were significantly correlated with titrable acid and sugar-acid ratio. The results of RDA analysis showed that organic matter content，available P content，mean temperature difference and pH were the key factors affecting fruit quality.

Key words: apple, fruit quality, environmental factors, correlation