Molecular Plant Breeding 2024, Vol.15, No.5, 269-281 http://genbreedpublisher.com/index.php/mpb 272 2021). These economic and labor-intensive challenges underscore the need for modern breeding techniques and technological advancements to improve the efficiency and cost-effectiveness of sugarcane cultivation. By addressing these challenges through modern breeding techniques and sustainable cultivation practices, the potential for improving sugarcane yield and resilience can be significantly enhanced. 5 Advances in Sugarcane Breeding 5.1 The Transition from traditional breeding to modern techniques The transition from traditional breeding to modern techniques in sugarcane has been driven by the need to overcome the challenges posed by the crop’s genetic complexity and low fertility under natural conditions. Traditional breeding methods, which involve visual clonal selection and manual screening for traits such as cane stalk weight and sugar content, are laborious and time-consuming, often taking 10 to 12 years to complete a breeding cycle (Luo et al., 2023). The advent of genetic engineering and molecular marker-assisted selection (MAS) has revolutionized sugarcane breeding by enabling more precise and efficient selection processes. Techniques such as electroporation, Agrobacterium tumefaciens-mediated transformation, and biobalistics have been developed to introduce desirable traits like herbicide resistance, disease resistance, and improved tolerance to environmental stresses. Despite these advancements, the genetic transformation of sugarcane remains a technical challenge due to the need for optimized tissue culture and plant generation procedures for each genotype (Budeguer et al., 2021). 5.2 Hybridization and the development of high-yield varieties Hybridization has played a crucial role in the development of high-yield sugarcane varieties. Modern sugarcane cultivars are interspecific hybrids derived from crosses between Saccharum officinarum and Saccharum spontaneum, resulting in highly polyploid and aneuploid genomes (Yang et al., 2018; Luo et al., 2023). This genetic complexity has been harnessed to introduce agronomically useful traits such as high sucrose content, disease resistance, and stress tolerance. The use of molecular markers, such as simple sequence repeats (SSR) and single nucleotide polymorphisms (SNP), has facilitated the identification and selection of desirable traits in breeding programs (Thirugnanasambandam et al., 2018; Wu et al., 2019). For instance, SSR markers combined with high-performance capillary electrophoresis have been used to genotype sugarcane parental lines, aiding in the selection of the best parents for crossing and the evaluation of progeny (Wu et al., 2019). Additionally, genomic selection (GS) using SNP markers has shown promise in improving traits like cane yield and sugar content by providing a more robust estimation of genetic merit (Luo et al., 2023). 5.3 The role of polyploidy and genetic complexity in breeding programs Polyploidy and genetic complexity are defining features of sugarcane that present both challenges and opportunities for breeding programs. The large, complex polyploid genome of sugarcane, with chromosome numbers ranging from 100 to 130, complicates traditional breeding efforts but also offers a rich source of genetic diversity (Luo et al., 2023). Advances in genomics and sequencing technologies have enabled the detailed characterization of sugarcane’s genetic makeup, revealing the contributions of different progenitor species and the extent of linkage disequilibrium (Lu et al., 2004). These insights have informed breeding strategies aimed at leveraging the genetic diversity within sugarcane populations to develop improved cultivars. For example, the sequencing of sugarcane germplasm accessions has identified candidate genes associated with environmental adaptation and selection, providing valuable resources for breeding programs (Yang et al., 2018). Furthermore, the integration of genomic data with phenotypic information through high-throughput phenotyping and genomic selection holds the potential to accelerate the development of high-yield, stress-tolerant sugarcane varieties (Mahadevaiah et al., 2021; Luo et al., 2023). 6 Genomic and Molecular Breeding Approaches 6.1 Integration of genomic selection and marker-assisted breeding in sugarcane The integration of genomic selection (GS) and marker-assisted breeding (MAB) has shown significant promise in accelerating genetic gains in sugarcane breeding programs. Traditional breeding methods in sugarcane are time-consuming, often requiring 10~14 years for varietal identification due to the complex polyploid nature of the
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