International Journal of Horticulture, 2024, Vol.14, No.4, 237-249 http://hortherbpublisher.com/index.php/ijh 244 Thinning flowers and fruits not only reduces competition among fruits, ensuring each fruit receives sufficient nutrients and water, but also promotes uniform growth. If thinning is not performed, an excessive number of fruits can lead to a reduction in sugar content, adversely affecting taste and market acceptance (Zhai et al., 2015; Costa et al., 2018). Specific practices include removing deformed flowers and excess buds during the flowering period, and eliminating excess young fruits based on the tree's bearing capacity during the fruit setting period. Through proper thinning management, the fruit quality of thornless yellow dragon can be effectively enhanced, increasing its market competitiveness and supporting the sustainable and healthy development of the dragon fruit industry. Figure 6 Fruit of deformed flowers of thornless yellow dragon Table 1 Characteristics of different batches of thornless yellow dragon fruits No. Peel thickness Central sugar content (% Brix) Weight (g) Number of scales First batch Uneven 16.2 311.2 14.2 Second batch Thick 17.75 324.25 18 Note: The first batch comes from new shoots, while the second batch comes from mature old branches 4.2.2 Rational fertilization In the cultivation of thornless yellow dragon, rational fertilization is crucial for ensuring healthy growth and high yield. One day before flowering, applying 3-5 kg of calcium-magnesium fertilizer per mu helps promote the closure of the pistils, preventing bacterial invasion of the fruit and reducing the occurrence of fruit rot. During the first fruit enlargement phase, which is three days after the flowers fall, applying 3-5 kg per mu of a 15:9:30 NPK (nitrogen, phosphorus, potassium) water-soluble fertilizer promotes rapid fruit enlargement. Seven to ten days later, using a balanced fertilizer replenishes the tree's phosphorus, aiding the next flowering. When the fruit begins to change color, applying a 0:30:40 NPK water-soluble fertilizer encourages sugar accumulation, increasing sweetness. After harvesting, applying a 20:20:20 NPK balanced fertilizer at 3-5 kg per mu replenishes the tree's nutrients, preparing it for the next batch of flowers and fruits. By using different types and ratios of fertilizers at various growth stages, the nutritional needs of thornless yellow dragon are met, promoting healthy growth and improving fruit quality and sweetness, thereby enhancing market competitiveness. 4.2.3 Chemical spraying To increase fruit sweetness and maintain scale integrity, a specific chemical spraying regimen is employed. Seven days after the flowers fall, a water-soluble solution containing 100 ppm gibberellin, 10 ppm forchlorfenuron, and 1,000 ppm slow-release nitrogen fertilizer is sprayed on the entire fruit. Subsequently, 20 days after flowering, during the fruit coloring stage, the fruit is bagged. Fruits treated this way reach peak sweetness 35 days after
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