Molecular Plant Breeding 2024, Vol.15, No.4, 187-197 http://genbreedpublisher.com/index.php/mpb 192 Figure 3 Schematic overview of the phenotypic selection breeding program (PS) (Adopted from Lubanga et al., 2022) Image caption: the dashed line represents the stage at which the 5 or 20 new parents are selected based on phenotypic information. PT, Preliminary Trial stage; ACT, Advanced Clonal Trial stage and ECT, Elite Clonal Trial stage (Adopted from Lubanga et al., 2022) These case studies underscore the impact of MAS in overcoming traditional breeding challenges and achieving significant advancements in Camellia breeding programs. By leveraging the power of genetic markers, breeders can continue to develop innovative and high-performing Camellia varieties that meet the demands of both ornamental horticulture and the tea industry. 5 Advances in Genomic Technologies and Their Impact on MAS 5.1 Next-generation sequencing (NGS) and genotyping-by-sequencing (GBS) Next-Generation Sequencing (NGS) technologies have revolutionized the field of genomics by providing high-throughput, cost-effective, and accurate sequencing of DNA. Genotyping-by-Sequencing (GBS) is a specific application of NGS that allows for the rapid and simultaneous discovery and genotyping of single nucleotide polymorphisms (SNPs). These technologies enable the identification of thousands of genetic markers across the genome, providing high-resolution genetic maps for MAS (Abebe, 2019). Furthermore, NGS and GBS significantly reduce the cost and time required for genotyping compared to traditional methods, facilitating the precise mapping of quantitative trait loci (QTL) and the identification of markers closely linked to desirable traits. In Camellia sinensis, NGS and GBS have been employed to identify SNPs associated with important traits such as tea quality and disease resistance. These markers are now being used in MAS programs to select for superior tea cultivars. The dense marker coverage provided by these technologies enhances trait mapping and enables breeders to make more informed selections, ultimately improving the efficiency and effectiveness of Camellia breeding programs. 5.2 Genome-wide association studies (GWAS) Genome-Wide Association Studies (GWAS) involve scanning the entire genome of a population to identify genetic variants associated with specific traits. GWAS relies on the high-density marker data generated by Next-Generation Sequencing (NGS) and Genotyping-by-Sequencing (GBS). This approach provides detailed insights into the genetic basis of complex traits by identifying multiple loci that contribute to trait variation, enabling the discovery of novel genetic markers associated with economically important traits, which can be directly used in Marker-Assisted Selection (MAS). By utilizing markers identified through GWAS, breeders can achieve higher selection accuracy and genetic gain (Luo et al., 2023).
RkJQdWJsaXNoZXIy MjQ4ODYzMg==