Plant Gene and Trait 2024, Vol.15, No.6, 275-284 http://genbreedpublisher.com/index.php/pgt 278 of sweet potato accessions from Brazil showed a high level of genetic variability, which is crucial for breeding programs aiming to improve sweet potato traits (Ghebreslassie et al., 2016). These findings underscore the importance of molecular approaches in enhancing our understanding of sweet potato genetic diversity and guiding conservation and breeding efforts. 5 Genetic Diversity in Sweet Potato Germplasm from Asia 5.1 Genetic diversity analysis of sweet potato germplasm in Asia The genetic diversity of sweet potato germplasm in Asia has been extensively studied using various molecular markers. For instance, a genome-wide assessment of 197 sweet potato accessions, primarily from China, utilized 62 363 SNPs to evaluate genetic diversity and population structure. This study identified three distinct genetic groups and highlighted significant genetic variation within the accessions, with a mean genetic distance ranging from 0.290 to 0.311 (Figure 1) (Su et al., 2017). Another study employed retrotransposon-based insertion polymorphism (RBIP) markers to analyze 105 sweet potato germplasm resources from China, Japan, and America. This analysis revealed high polymorphism (91.07%) and significant genetic variation among the accessions, which were divided into three groups (Meng et al., 2021). Figure 1 Location of the sweet potato accessions from around the world, highlighting China (Adopted from Su et al., 2017) 5.2 Research background and data sources The research on sweet potato genetic diversity in Asia has been driven by the need to enhance breeding programs and conserve genetic resources. The studies have utilized germplasm collections from various national and international gene banks. For example, the National Agrobiodiversity Center (NAC) in South Korea has been a significant source of germplasm for genetic diversity studies. One study analyzed 558 sweet potato accessions from the NAC using chloroplast SSR markers, revealing low genetic diversity among the female parents and the need for more diverse collections (Lee et al., 2019). Additionally, the International Potato Center (CIP) has contributed to the understanding of genetic diversity by maintaining a vast collection of sweet potato accessions from around the world, including Asia (Zhang et al., 2000). 5.3 Key findings and their significance for global sweet potato diversity conservation The key findings from these studies underscore the rich genetic diversity present in Asian sweet potato germplasm. The identification of distinct genetic groups and high levels of polymorphism suggests that Asian germplasm can significantly contribute to global sweet potato breeding programs. The low genetic diversity observed in some collections, such as those from the NAC, highlights the importance of expanding germplasm collections to include more diverse accessions (Figure 2) (Lee et al., 2019; Luo et al., 2023). The development of core germplasm sets, as seen in the study using SNP markers, provides valuable resources for future breeding efforts. Furthermore, the use of advanced molecular markers like RBIP and SSRs has proven effective in characterizing genetic diversity and can be applied to other regions to enhance global conservation strategies (Monteros-Altamirano et al., 2020). These findings are crucial for the conservation of sweet potato genetic resources, as they provide insights into the genetic structure and diversity of germplasm collections. By identifying areas with low genetic diversity, researchers can prioritize these regions for new germplasm collection efforts. Additionally, the development of core germplasm sets ensures that the most genetically diverse and representative accessions are preserved and utilized in breeding programs, ultimately contributing to the sustainability and improvement of sweet potato crops worldwide.
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