## 2 Materials and Methods
### Investigation of Fruiting Characteristics  
(1) Fruit-setting rate: the number of fruit-bearing flowers accounted for the percentage of total flowers. The number of flowers on all the branches in each test group was counted during the flowering period. When the fruit reached the fruit-setting standard (diameter of 0.8 cm), the number of flowers on all the branches was counted, and the fruit-setting rate of each branch was calculated. The average fruit-setting rate of all the branches was used as the fruit-setting rate of the flowers in the test group.  
\[\text{Fruit-setting rate of each marked branch }(\%)=\frac{\text{the number fruit-bearing flowers}}{\text{total flowers}} \tag{1}\]  
\[\text{Fruit-setting rate }(\%)=\frac{\text{sum of fruit-setting rates of all labeled branches}}{\text{number of all tagged branches}} \tag{2}\]  
(2) Calyx abscission rate: the percentage of fruits with calyx abscission to the total fruit number. Natural fruit drop occurs on the fragrant Korla pear tree branches. When the color of the young fruit calyx tube begins to change slowly, it is considered a critical period of shedding. Starting from the critical period of shedding, the number of fruit settings and calyx fruits on all the marked branches were investigated daily until the number of calyx fruits no longer changed. The average calyx-removal rate of all the branches was used as the calyx-removal rate for the test group.  
\[\text{Calyx abscission rate of each marked branch }(\%)=\frac{\text{the number of fruits with calyx abscission}}{\text{total fruit number}} \tag{3}\]  
Figure 1: The distribution map of the trees in the pear orchard. YB represents the grafting tree of Korla fragrant pear bud mutation material, and CK represents the Korla fragrant pear tree.  
Calyx abscission rate \((\%)=\dfrac{\text{sum of calyx abscission rates of all labeled branches}}{\text{number of all tagged branches}}\) (4)  
(3) Fruit quality: in terms of appearance quality measurement, 10 fruits were randomly selected from the fruits collected in each test group. A Vernier caliper was used to measure the transverse diameter (cm) and longitudinal diameter (cm) of the fruit, and the fruit shape index (the longitudinal diameter to transverse diameter ratio) was calculated. The single fruit weight (g) was measured with an electronic balance. The volume (cm\({}^{3}\)) of the fruit was measured by the drainage method, and the specific gravity (g/cm\({}^{3}\)) of the fruit (the weight to volume ratio) was calculated. After removing the core, the pulp was weighed (g) and the edible rate (%) (the ratio of pulp weight to single fruit weight) was determined. Ten fruits were randomly selected from the fruits of each test group, and the fruit skin hardness (kg\(\cdot\)cm\({}^{-2}\)) and fruit peel hardness (kg\(\cdot\)cm\({}^{-2}\)) were measured using a GY-B3 fruit hardness tester. In terms of the internal quality determination, 10 fruits were randomly selected from the fruits of each test group, and the soluble solid content (%) in the fruits was determined by the refracometer method [36]. The total acid content (g/kg) in the fruit was determined by the determination method of total acid in food, and the ratio of sugar to acid (the ratio of soluble solids content to total acid content) was calculated [37]. The soluble sugar content (%) of fruit was determined by the 3,5-dinitrosalicylic acid colorimetric method [38], and the fruit moisture content (%) was determined by the moisture content determination method in food [39]. The vitamin C content (mg/100 g) in the fruit was determined by the ascorbic acid determination method in food [40]. The soluble protein content (mg/g) of the fruit was determined by Coomassieie brilliant blue staining [41]. The stone cell content (%) (the stone cell weight to pulp weight ratio) was determined by the gravimetric method [42].