International Journal of Horticulture, 2024, Vol.14, No.4, 237-249 http://hortherbpublisher.com/index.php/ijh 240 2.2 Root characteristics of thornless yellow dragon The root system of thornless yellow dragon is more vigorous compared to the red-pulp dragon fruit. Its underground roots are not only well-developed but also possess a stronger resistance to nematodes, which contributes to the plant's excellent performance in resisting pests and diseases (Long et al., 2020). Additionally, the aerial stems of thornless yellow dragon are prone to developing aerial roots. Once these aerial roots reach the ground, they transform into underground roots, further enhancing the plant's stability and absorption capacity (Figure 3). This unique root structure provides thornless yellow dragon with a strong adaptability to various environments. Figure 3 Vigorous root system of thornless yellow dragon Thornless yellow dragon not only has strong pest and disease resistance but can also be used as a rootstock. By grafting varieties such as red-pulp dragon fruit or the bird's nest fruit onto thornless yellow dragon, the nematode resistance of these grafted varieties can be improved. This grafting method effectively leverages the robust root system of thornless yellow dragon, enhancing the growth performance and pest resistance of the grafted varieties. This approach not only improves the overall yield and quality of dragon fruit but also effectively reduces the impact of pests and diseases, promoting the sustainable development of the dragon fruit industry. 2.3 Flowering period and fruit development characteristics of thornless yellow dragon The flowering period of thornless yellow dragon overlaps with that of Jindu Dragon Fruit. In Hainan, China, through supplementary lighting technology, it is possible to achieve over 20 flowering batches annually (Xiong et al., 2020). Thornless yellow dragon requires about 18 days from the initial appearance of flower buds to flowering, but this process can extend to 30 days during extremely cold winter periods. Starting from May each year, the interval between each batch of flowers is approximately 15 days. During extremely hot weather, a new batch of flowers can appear weekly. For example, in July, the flowering time for thornless yellow dragon is typically at 9 pm, which is half an hour later than Jindu Dragon Fruit, and the flowers close by 9 am the next day. During the flowering of thornless yellow dragon, its stigma is noticeably higher than the stamens, characterizing it as a typical cross-pollination flower (Figure 4). This floral structure facilitates cross-pollination, enhancing the fruit set rate and quality (Cho and Ding, 2021). Through reasonable cultivation management and supplementary lighting technology, the flowering period of thornless yellow dragon can be effectively controlled, ensuring a stable and continuous yield and quality throughout the year. The application of this technology not only increases the market supply of thornless yellow dragon but also brings higher economic benefits to farmers. 2.4 Short fruit hanging period and re-greening phenomenon of thornless yellow dragon Seven days after the flowers of thornless yellow dragon fade, the fruit begins its first enlargement phase. After 23 days, the peel starts to change color from green to yellow. This color change process lasts about a week, during which the fruit enters its second enlargement phase. On the 30th day after flowering, the peel begins to re-green, and the scales start to thin and soften, with the tips even showing signs of drying. By the 40th day, the fruit tips
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