Tree Genetics and Molecular Breeding 2025, Vol.15, No.1, 1-8 http://genbreedpublisher.com/index.php/tgmb 5 2024). Selecting cultivars with elevated DzARF2A expression could lead to varieties that ripen more quickly and produce higher yields, as observed in the fast-ripening Chanee compared to the slower-ripening Monthong. Additionally, the differential expression of Dof transcription factors (DzDofs) during fruit development suggests potential targets for enhancing auxin biosynthesis and fruit yield (Nawae et al., 2023). 5.2 Application of hormonal regulation techniques in yield enhancement Modulating key phytohormones, including auxin and ethylene, provides another approach to increasing durian yields. The upregulation of DzARF2A and its role in activating ethylene biosynthesis genes highlight the potential of applying exogenous auxin to accelerate fruit ripening and enhance production (Husin et al., 2018). This technique could be particularly effective in fast-ripening cultivars like Chanee, where higher auxin levels correlate with increased DzARF2A expression. Similarly, enhancing DzDof2.2 expression, which is associated with auxin biosynthesis, may further boost auxin levels and initiate the ethylene response earlier, potentially improving fruit yield and consistency (Santoso et al., 2017). 5.3 Future prospects for molecular breeding in durian The integration of genomic and transcriptomic data is paving the way for advanced molecular breeding in durian. The identification of regulatory genes such as DzARF2A and DzDof2.2, both of which play essential roles in auxin and ethylene signaling, provides opportunities for developing improved durian cultivars with enhanced fruit quality and yield (Huang, 2024). With advancements in gene-editing tools like CRISPR/Cas9, targeted modifications to these genes could lead to varieties with optimized ripening characteristics and greater resistance to environmental stress. As research continues to uncover the genetic foundations of tree size and fruit yield, breeders will be better equipped to cultivate high-yielding, resilient durian varieties suited to both producer needs and consumer preferences (Huy et al., 2023). 6 Future Research Directions 6.1 Further elucidation of auxin and cytokinin regulatory networks in durian Auxin and cytokinin play essential roles in durian tree development and fruit ripening, but their precise regulatory mechanisms remain insufficiently understood. Research has linked auxin response factors (ARFs), particularly DzARF2A, to ethylene biosynthesis, which accelerates ripening in some cultivars. Future studies should focus on mapping the complete auxin and cytokinin signaling pathways and their interactions, which could reveal new targets for genetic improvement aimed at optimizing fruit yield and quality (Lin, 2020). 6.2 Advances in durian genomics and precision breeding technologies The identification of key transcription factors, such as DzDofs, associated with auxin biosynthesis and cultivar-specific ripening characteristics, underscores the potential of genomic research in durian breeding. With developments in genomic tools like CRISPR/Cas9, researchers have the opportunity to create improved durian varieties with enhanced traits (Cheng et al., 2021). Future efforts should focus on integrating genomic data with phenotypic traits to refine breeding strategies, ultimately leading to cultivars with higher yields and improved fruit quality (Tang et al., 2024). 6.3 Strategies for enhancing durian yield and quality by hormonal balance regulation Achieving a balance between auxin and cytokinin is crucial for maximizing durian fruit yield and quality. Auxin-ethylene crosstalk, as demonstrated by the role of DzARF2A in ethylene biosynthesis regulation, offers a framework for adjusting hormonal pathways to control ripening and enhance fruit development (Desta and Amare, 2021). Future research should explore genetic and agronomic techniques to fine-tune hormonal levels, aiming for an optimal balance that improves yield consistency while preserving fruit quality (Ngoc et al., 2024). 7 Concluding Remarks The genetic factors influencing durian tree size and fruit yield are closely tied to hormonal signaling pathways, particularly those involving auxin and cytokinin. Auxin plays a fundamental role in fruit ripening, as indicated by the identification of auxin response factors (ARFs) that regulate ethylene biosynthesis, a key hormone in the ripening of climacteric fruits. Specifically, DzARF2A has been found to upregulate ethylene biosynthetic genes,
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