###### Abstract
When PP333 was sprayed at the flowering stage of Korla fragrant pears, there were only vessels in the calyx tubes of young fruits, and there were no sieve tube cells or heterocytes. At the late calyx tube development stage, an abscission layer appears, the calyx tube falls off, and a calyx-free fruit finally forms [10]. Although artificial pollination can improve the fruit-setting rate of Korla fragrant pear, it is very costly for large-scale planting orchards [3]. Plant growth regulators can increase the calyx-removal rate of Korla fragrant pears, but excessive plant growth regulator use affects fruit quality. Studies have shown that spraying NAA plant growth regulators can promote fruit thinning, but simultaneously cause plant leaf deformity, inhibit fruit hypertrophy, and lead to dwarf fruit [11]. Spraying uniconazole can effectively increase the calyx-removal rate and fruit weight of Korla fragrant pears, but inhibits the growth of new shoots, internode length, and leaf area of Korla fragrant pears, increases the coarse-skinned fruit ratio, and increases fruit hardness and stone cell content [12]. Nowadays, consumers pay more attention to the quality and safety of agricultural products, and the demand for green organic agricultural products is increasing. Therefore, to promote the healthy and sustainable development of the Korla fragrant pear industry and meet the growing demand for green organic food by consumers today [13; 14; 15], breeding varieties with excellent fruiting characteristics under natural conditions is the most effective measure. Korla fragrant pears are mostly bred using bud mutations. Compared to traditional hybrid breeding methods, bud mutation breeding [16; 17; 18] can avoid interference in early development, has a short periodicity, and can improve individual shortcomings while essentially retaining the comprehensive traits of the original variety, thereby streamlining the breeding process and shortening the breeding cycle. Currently, the bud mutation varieties of Korla fragrant pear mainly include the 'Sha 01' line and the 'Xinli 2' line [19; 20]. Compared with Korla fragrant pear, the bud mutation characteristics of the 'Sha 01' and 'Xinli 2' strains were mainly reflected in the large single fruit volume, low stone cell content, and early maturity, but the low fruit-setting rate and low calyx-removal rate problems were not improved. In terms of fruit quality, the unique flavor of Korla fragrant pears is composed of several quality indicators, but the existing bud mutant varieties (lines) failed to improve one or more quality indicators while maintaining the original quality. In this research, we compared the fruit quality of Korla fragrant pear bud mutant material with that of Korla fragrant pear to better understand the fruit quality of Korla fragrant pear bud mutant material under natural conditions. The breeding of bud mutation materials plays an important role in fruit tree breeding [21]. However, whether the bud mutation material can be used and whether it is a high-quality germplasm resource need to be identified. At present, GBS sequencing technology and molecular marker technology have been widely used in the identification of plant germplasm resources. GBS sequencing technology can be used to analyze the genetic background and genetic diversity of different germplasm resources [22; 23]. Analysis of population genetic diversity is crucial for cultivating new varieties and evaluating and utilizing plant germplasm resources. They are an important component of plant genetics, breeding, protection, and evolution [24]. This has been reported in the research of germplasm resources of maize (_Zea mays_) [25], rice (_Oryza sativa_) [26], pepper (_Capsicum_ spp.) [27], _Camelina sativa_[28], watermelon (_Citrullus lanatus_) [29], and other species. It can be seen that GBS sequencing technology is of great significance in the identification, preservation, and utilization of germplasm resources.