Tree Genetics and Molecular Breeding 2024, Vol.14, No.6, 295-303 http://genbreedpublisher.com/index.php/tgmb 300 5.3 Lessons learned and future applications The case studies highlight the importance of genetic diversity in breeding programs, DGF4 exhibited significant advantages in total phenolic, flavonoid, and β-carotene content, with particularly high antioxidant activity in the peel. DGF2 excelled in antioxidant capacity and xanthophyll content, while DGF3 stood out for its high accumulation of carotenoids and xanthophyll. These findings provide a scientific basis for evaluating the nutritional value and functional properties of dragon fruit genotypes, offering insights into varietal selection and breeding strategies to meet market demands for highly nutritious and antioxidant-rich fruits. 6 Discussion 6.1 Key findings from the meta-analysis The meta-analysis of genetic markers for yield and quality traits in dragon fruit has revealed significant genetic diversity among different genotypes. Studies utilizing Inter-Simple Sequence Repeat (ISSR) markers have demonstrated high polymorphism, with polymorphic bands ranging from 25% to 100% and an average polymorphism information content (PIC) of 0.85, indicating substantial genetic variation (Saini et al., 2021). This diversity is crucial for breeding programs aimed at improving yield and quality traits. The genetic differentiation coefficient (Fst) of 0.26 further supports the presence of considerable genetic diversity within dragon fruit populations, which is essential for developing genotypes with superior traits (Salazar et al., 2020). 6.2 Challenges in applying genetic markers to breeding Despite the promising findings, several challenges exist in applying genetic markers to dragon fruit breeding. One major challenge is the discrepancy observed between morphological traits and ISSR loci, which complicates the accurate assessment of genetic relatedness (Lin et al., 2024). Additionally, the limited number of genetic studies in certain regions, such as Colombia, highlights the need for more comprehensive research to fully understand the genetic architecture of dragon fruit (Morillo et al., 2022). The integration of genetic markers into breeding programs also requires significant resources and expertise, which may not be readily available in all breeding contexts. 6.3 Comparison with other crops When compared to other crops, such as Indian mustard, the genetic analysis of dragon fruit is still in its nascent stages. In Indian mustard, meta-QTL analysis has identified robust and stable meta-QTLs for yield and quality traits, with significantly reduced confidence intervals, facilitating more precise breeding strategies (Saini et al., 2021). In contrast, dragon fruit research is primarily focused on genetic diversity and structure, with less emphasis on identifying specific QTLs for targeted breeding. This highlights the potential for dragon fruit breeding programs to benefit from methodologies applied in more extensively studied crops. 6.4 Future prospects for marker-assisted breeding The future of marker-assisted breeding in dragon fruit looks promising, with the potential to significantly enhance yield and quality traits. The high genetic diversity observed provides a rich resource for selecting desirable traits (García-Gómez et al., 2019). Future research should focus on identifying specific QTLs associated with key traits, similar to the approaches used in Indian mustard, to enable more targeted breeding efforts (Salazar et al., 2020). Additionally, advancements in genetic engineering and genome editing technologies could further accelerate the development of improved dragon fruit varieties, offering resistance to biotic and abiotic stresses and meeting market demands for high-quality produce. 7 Conclusion The meta-analysis of genetic markers for yield and quality traits in dragon fruit has provided significant insights into the genetic diversity and potential for breeding improvements in this economically valuable fruit. The study synthesized data from various genetic analyses, highlighting the substantial genetic variability present in dragon fruit populations, as evidenced by the high percentage of polymorphic loci and genetic diversity indices observed in studies from different regions. This genetic diversity is crucial for breeding programs aimed at enhancing yield and quality traits, as it provides a broad genetic base from which to select superior genotypes.
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