International Journal of Molecular Ecology and Conservation, 2025, Vol.15, No.1, 30-43 http://ecoevopublisher.com/index.php/ijmec 37 cultivation and artificial pollination, growers have achieved an average annual output of tens of thousands of tons of commercial fruit. It is reported that the area of dragon fruit cultivation in Vietnam has maintained a rapid growth trend in recent years, with an average annual growth rate of more than 10% between 2015 and 2020, and the industry prospects are widely optimistic (Zeng et al., 2021). However, studies have pointed out that the scientific research support for dragon fruit in Vietnam is relatively lagging, and investment in breeding of improved varieties and disease prevention is insufficient. For example, pitaya stem blight and canker diseases occur frequently in Vietnam, causing losses in production, and the corresponding prevention and control technologies and research and development of disease-resistant varieties need to be strengthened. In addition, market fluctuations and climate factors (such as extreme high temperatures or floods) also bring uncertainty to the industry. In response to these problems, the Guangxi Academy of Agricultural Sciences and other institutions cooperated with Vietnam to conduct research and proposed that an international germplasm resource sharing platform and scientific research cooperation alliance should be established to jointly cultivate new varieties suitable for Vietnam and surrounding areas, and at the same time strengthen cultivation management training to improve the industry's risk resistance. Vietnam's experience shows that even if a region has superior natural conditions, it may face challenges after scale expansion if it lacks scientific and technological support and diversified operations. 7.2 Performance and selection in local Agroecological zones Thailand is also a case of successful adaptation of pitaya in Southeast Asia. Some areas in central and northeastern Thailand use orchard intercropping and family courtyards to grow pitaya. With abundant local sunshine and labor resources, the pitaya industry has developed. The Thai agricultural sector actively introduced excellent varieties from Vietnam and Taiwan, such as the red-fleshed "Big Red" and the white-fleshed "Big Mac", and at the same time selected some strains suitable for local tastes and climate. Thai farmers focus on organic cultivation and extending the fruiting period. By adjusting watering and fertilization, pitaya can be evenly available almost all year round to meet the needs of tourism and exports. It is reported that some planting areas in Thailand have controlled light to induce off-season flowering, so that pitaya can also bear fruit in the traditional off-season, thereby improving economic benefits (Trivellini et al., 2020). These measures show that pitaya has a strong responsiveness to artificial cultivation regulation, which is another manifestation of its regional adaptability (Figure 2) (Al-Qthanin et al., 2024). 7.3 Cultivar development and market integration outcomes In addition to Vietnam and Thailand, Malaysia, the Philippines and other countries have also gradually expanded the scale of pitaya cultivation. Malaysia has accumulated certain experience in controlling pests and diseases, such as reducing the incidence of stem blight by more than 60% through pruning and clearing the garden (Dutra et al., 2025). The Philippines uses volcanic ash soil to grow pitaya, and the fruit has a unique flavor and is branded. In Southeast Asia, countries have also carried out experience exchanges, such as establishing a dragon fruit industry association to hold annual seminars to share information on new varieties and new technologies. These cross-regional collaborations have further promoted the adaptation and promotion of dragon fruit in Southeast Asia. 8 Constraints and challenges of germplasm utilization 8.1 Genetic bottleneck and low pollination rate Most of the widely planted yellow pitaya varieties are derived from a few introduced materials and have a high degree of homogeneity. Some main varieties (such as the Vietnamese white-fleshed variety) account for too large a proportion of the planting area. Once they encounter an unfavorable environment or a new pathogen, they may fail as a whole. For example, many places use red-fleshed pitaya varieties introduced from Vietnam. These varieties are highly similar in genetics and have similar disease resistance spectra. Therefore, when stem blight or other diseases break out in the region, all plots are often infected at the same time, resulting in heavy losses. The narrow genetic base also limits the space for further breeding improvements. For some traits (such as cold resistance), the currently available allelic variation is limited, which slows down breeding progress. Therefore, it is necessary to introduce and create more germplasm variation, including distant hybridization of wild relatives, new alleles obtained by mutagenesis, etc., to broaden the genetic background (Ding et al., 2024).
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