Journal of Tea Science Research, 2024, Vol.14, No.4, 202-214 http://hortherbpublisher.com/index.php/jtsr 206 4 Genetic Diversity Study of Tea Germplasm Resources 4.1 Overview of genetic diversity in tea germplasm resources Genetic diversity is crucial for the adaptability and resilience of tea plants (Camellia sinensis) to various biotic and abiotic stresses. It provides a pool of genetic traits that can be utilized for breeding programs aimed at improving tea quality, yield, and resistance to diseases and environmental stresses. For instance, the study of tea germplasm in Wuyishan revealed significant genetic diversity, which is essential for the effective protection and utilization of these resources (Liu et al., 2022). Similarly, the genetic diversity of oolong tea germplasms has been shown to be vital for breeding and quality control (Lin et al., 2019). Several factors influence the genetic diversity of tea germplasm, including geographical location, cultivation practices, and natural selection. For example, the genetic diversity of tea plants in Ningde and its adjacent regions is shaped by the interaction of local landraces with wild-type plants (Zhu et al., 2023). Additionally, human activities and environmental conditions can lead to genetic differentiation, as observed in the tea germplasm of Wuyishan, where population differentiation has occurred due to geographical isolation (Liu et al., 2022). 4.2 Research methods and techniques for genetic diversity Phenotypic methods involve the assessment of observable traits such as leaf size, shape, and biochemical composition. For instance, the phenotypic diversity of ancient tea plant germplasm in Sandu County was evaluated using traditional methods, revealing high levels of diversity (Zhao et al., 2021). These methods are often complemented by molecular techniques to provide a comprehensive understanding of genetic diversity. Genome-based techniques, such as the use of single nucleotide polymorphism (SNP) markers, simple sequence repeats (SSR), and amplified fragment length polymorphism (AFLP), are widely used to analyze genetic diversity. SNP markers were employed to study the genetic diversity of tea germplasm in Wuyishan and Ningde, providing insights into population structure and genetic relationships (Liu et al., 2022; Zhu et al., 2023). SSR markers have been used to assess the genetic diversity of tea germplasm in Korea and Russia, revealing significant molecular variability (Lee et al., 2019; Samarina et al., 2022). AFLP markers have also been utilized to distinguish between different tea cultivars in South India, highlighting the need for preserving genetic resources (Balasaravanan et al., 2003). 4.3 Research progress in genetic diversity of tea germplasm resources Recent studies have made significant progress in analyzing the genetic diversity of various tea germplasms. For example, the genetic diversity of 137 tea germplasms from Wuyishan was analyzed using SNP markers, revealing rich genetic diversity and population differentiation (Liu et al., 2022). Similarly, the genetic diversity of 100 oolong tea landraces was assessed using high-throughput SNP technology, providing valuable information for breeding programs (Lin et al., 2019). In Russia, SSR markers were used to analyze the genetic diversity of tea germplasm, identifying distinct genetic clusters (Samarina et al., 2022). Conservation efforts are crucial for maintaining the genetic diversity of tea germplasm. The development of core collections, such as the target-oriented core collection (TOCC) in tea germplasm, helps retain genetic diversity and various phytochemicals, facilitating effective utilization in breeding programs (Hyun et al., 2020). In Korea, the genetic diversity of tea germplasm has been assessed to inform conservation strategies, emphasizing the need for collecting new individuals to broaden genetic variation (Lee et al., 2019). Additionally, the identification of unique tea germplasms, such as the albino tea plant Menghai Huangye, highlights the importance of preserving special traits for future breeding efforts (Pang et al., 2021). The study of genetic diversity in tea germplasm resources is essential for the sustainable development and improvement of tea cultivation. Various research methods and techniques have been employed to analyze genetic diversity, and significant progress has been made in understanding and conserving these valuable resources.
RkJQdWJsaXNoZXIy MjQ4ODYzNA==