Journal of Tea Science Research, 2025, Vol.15, No.1, 12-20 http://hortherbpublisher.com/index.php/jtsr 15 4 Advantages and Limitations of Traditional Breeding 4.1 Advantages: Stable genetic base and strong adaptability Traditional breeding tools such as phenotypic selection and clonal multiplication have established a solid genetic base in tea cultivars. These tools take advantage of local adaptation and natural genetic variability and yield cultivars with superior adaptability to diverse environments and capacity for withstanding local stresses. The use of elite local germplasm ensures that new varieties well fit specific regional conditions, which is a factor in sustainable tea production (Vavilova and Korzun, 2023). 4.2 Limitations: Long breeding cycles and low efficiency One of the major limitations of traditional tea breeding is its lengthy breeding period, usually over 16 years from choice to release of a cultivar. The process is tiresome and time-intensive, involving poor selection efficiency due to tea being a perennial crop and needing intensive field testing. It decelerates the rate of genetic advancement and delays the release of new varieties with desirable traits (Mukhopadhyay et al., 2015; Tuwei and Corley, 2019; Lubanga et al., 2022). 4.3 Insufficient understanding of complex trait genetic mechanisms Traditional breeding relies heavily on phenotypically expressed characters, which are often influenced by complex genetic and environmental interactions. The lack of in-depth understanding of the genetic mechanisms governing key agronomic and quality traits limits the precision of selection. The recent advances in genomics and multi-omics are now bridging these gaps, but traditional methods alone cannot yet stringently analyze complex trait inheritance (Xia et al., 2020; Yamashita et al., 2020). 4.4 Challenges in the conservation of genetic diversity in cultivars Whereas natural variation has been exploited by traditional breeding, recurrent selection and vegetative propagation have the potential to narrow the genetic base, which results in enhanced disease, pest, and environmental stress susceptibility. Conservation of genetic diversity is also constrained by limitations in utilization of wild relatives due to cross-incompatibility and genetic drag. Conservation of genetic diversity is being necessitated increasingly by including broader germplasm resources and newer molecular tools to conserve and enhance genetic diversity in tea breeding programs (Mukhopadhyay et al., 2015). 5 Integration Strategies of Traditional Breeding with Modern Molecular Breeding Technologies 5.1 Combining precise phenotyping with marker-assisted selection (MAS) Integration of phenotypic evaluation in detail with marker-assisted selection (MAS) enhances the precision and efficiency of selection in desirable characteristics in tea breeding. Molecular markers such as SNPs and SSRs are more and more used for the detection and tracing of genes related to yield, quality, and resistance against stresses, allowing breeders to make more precise decisions earlier in the breeding process and reduce the application of time-consuming field trials (Ranatunga, 2019). Bioinformatics software and massive databases also facilitate better genotypic and phenotypic data integration for MAS (Xia et al., 2019). 5.2 Complementary application of traditional hybrid breeding and genomic selection (GS) Traditional hybridization remains crucial for generating genetic diversity, whereas genomic selection (GS) employs genome-wide marker data to predict breeding values and propel genetic gain. Simulation experiments show that GS can greatly improve genetic gain as well as reduce breeding cycles relative to phenotypic selection alone, and is hence an effective complement to traditional hybrid breeding, especially in limited environments (Kumar et al., 2016; Yamashita et al., 2020). GS is most beneficial when applied early at seedling stages, thus making the selection more precise and affordable (Lubanga et al., 2022). 5.3 Collaborative innovation in utilizing traditional germplasm and functional gene mining The integration of traditional germplasm resources and emerging gene mining technologies, such as pangenomics and multi-omics, enables us to uncover new alleles and functional genes for key agronomic traits. The
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