JTSR_2024v14n4

Journal of Tea Science Research, 2024, Vol.14, No.4, 202-214 http://hortherbpublisher.com/index.php/jtsr 205 genotypes. For example, SSR markers have been used to analyze the genetic diversity of tea accessions in Korea, revealing significant genetic variation within populations (Lee et al., 2019). Similarly, SSR markers have been applied to study the genetic structure of ancient tea plant germplasm in China, providing valuable data for conservation and breeding programs (Zhao et al., 2021). SNP markers, identified through advanced sequencing technologies, offer high-resolution genetic information. They are useful for investigating the genetic background and breeding history of tea germplasm. For instance, Yamashita et al. (2019) analyzed the genetic structure of Japanese tea germplasm and landraces using ddRAD-seq technology, identifying over 10,000 SNP markers. The study revealed the genetic background and systematic structure of 167 tea samples, as well as the unique genetic background of the ‘Yabukita’ lineage, indicating that its genetic components are highly concentrated in Japanese tea breeding (Figure 1). Additionally, SNP markers have been employed to analyze the genetic diversity of oolong tea germplasm, aiding in the identification and selection of parent plants for breeding (Lin et al., 2019). Figure 1 Genetic structure among worldwide 167 tea accessions (Adopted from Yamashita et al., 2019) Image caption: . Inference of optimal K value by plotting of ΔK (A) and mean likelihood±S.D. (ten replicates) at each K (B). Estimated genetic structure at K = 2 and K = 3 (C). Plot of first and second principal components by PCA (D). Dendrogram of Ward’s hierarchical clustering based on Euclidean distance (E). Comparisons of distributions of three ancestral components among subgroups of Japanese var. sinensis, exotic var. sinensis, and Assam hybrids (F). Different letters above boxplots indicate significant differences (Steel-Dwass test, P< 0.05). Population analysis was performed with 13,715 SNPs among worldwide 167 tea accessions (Adopted from Yamashita et al., 2019)

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