Tree Genetics and Molecular Breeding 2025, Vol.15, No.1, 18-24 http://genbreedpublisher.com/index.php/tgmb 20 al. (2019) and Qi et al. (2023) also found that wild species have significant genetic differences in fruit sugar content, carotenoid content, chlorophyll content, etc. These characteristics are of great value for improving fruit quality and stress tolerance. 4.2 Case study: incorporating disease resistance traits from wild relatives Researchers often choose wild varieties in kiwifruit breeding projects because they value their genes for strong disease resistance. The varietal kiwifruit is regarded as an excellent breeding material due to its particularly strong resistance to canker disease. Its disease resistance comes from some special gene families, which have undergone positive selection to help it better resist diseases (Liu et al., 2017). The combination of interspecific hybridization and molecular marker selection can introduce useful traits into common commercial varieties. Scaglione et al. (2015) and Oh et al. (2018) demonstrated that techniques such as SNP markers and GBS can quickly identify plants with target traits from hybrid offspring, not only saving time but also enabling more accurate selection of the desired traits. Nazir et al.’s research in 2024 found that some new kiwi varieties with stronger disease resistance and better fruits were developed using this method (Figure 1). Figure 1 Integrative omics framework in kiwifruit breeding and trait enhancement (Adopted from Nazir et al., 2024) The research by Liao et al. (2017) and Hu et al. (2022) demonstrated that introducing wild kiwifruit varieties into the breeding system not only cultivated new varieties that are more adaptable to external pressure and have better taste, but also expanded the genetic basis of cultivated varieties, making them more resilient to climate change or new diseases. Shu et al. (2023) hold that this indicates the significance of protecting wild species, as these wild resources are crucial for enhancing the stability and competitiveness of the entire kiwifruit industry. 5 Challenges in Harnessing Genetic Diversity 5.1 Narrow genetic base in cultivated varieties Kiwifruit began to be commercialized on a global scale relatively late, and the breeding work was not systematic enough. Many varieties originated from very few genetic lineations (Zhang et al., 2015). This makes it difficult for
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