Animal Molecular Breeding, 2025, Vol.15, No.2, 91-101 http://animalscipublisher.com/index.php/amb 96 four algorithms (gBLUP, rrBLUP, BayesA, BayesC) under different conditions and found that the average AUC value was between 0.547 and 0.548, and the predictive ability of each method was similar (Ma and You, 2020). In C. macrochirus, the heritability estimates for these traits were moderate (0.29-0.31), while GS models such as GBLUP and BayesB showed high prediction accuracy when using GWAS-screened SNP datasets (Cui et al., 2024). GS also supports the use of low-density SNP marker combinations for prediction while maintaining high prediction accuracy, making it more cost-effective in large-scale breeding. Combining GWAS with GS can further improve selection accuracy, even in strains with diverse genetic backgrounds, thereby accelerating the promotion and application of GS in aquaculture breeding (Cui et al., 2024). 5.3 Hybridization and strain improvement inChanna Interspecific hybridization of Channa spp., such as the mating of Channa argus and Channa maculata, has produced hybrids that are superior to their parents in growth rate, survival rate, and stress resistance. The all-male hybrids obtained through sex control and cross breeding have an average daily weight gain of up to 17% and show a significant male-biased sex ratio, thereby maximizing economic benefits (Ou et al., 2018; Zhao et al., 2021). Hybrid strains combine the excellent traits of both male and female parents, like rapid growth, strong feed adaptability and low temperature tolerance, making them of great application value in diversified breeding environments. Ou et al. (2018) showed that the average weight of the hybrid NBS (C. argus ♀× C. maculata ♂) at six months of age was (421.3 ± 72.9) g, which was 124.6% and 71.5% higher than the maternal NS (187.6 ± 42.8) g and the paternal BS (245.6 ± 52.5) g (P<0.05), respectively, showing obvious hybrid vigor. The study also found that the hybrid inherited the easy training of BS and could quickly adapt to artificial formula feed; in the wintering experiment, even if the water temperature dropped to 0 °C-2 °C, the hybrid showed a similar high survival rate as NS, indicating that it has strong low temperature tolerance. 6 Case Studies 6.1 Genetic analysis of growth traits and breeding recommendations inChanna In the process of Channadomestication and breeding, growth traits are key indicators affecting economic benefits. However, molecular breeding research on this genus is still in its infancy, especially in terms of genetic variation and candidate gene screening. Liu et al. (2024) conducted the first genome-wide association study (GWAS) of growth-related traits by whole-genome resequencing and growth trait measurement of 500 Channa maculata, and identified 51 significant SNP loci and 13 candidate genes. The study found that the HS6ST1 gene is associated with body weight, body length, and total length, and may play a core role in muscle development and growth regulation (Figure 2) (Liu et al., 2024). The significant association between key traits (such as WT, TL, BL) and multiple chromosomal loci indicates the genetic diversity of this species in growth traits. This provides a powerful reference for subsequent molecular marker-assisted selection and breeding of superior strains in other species of the genus Channa. Another study systematically evaluated the feasibility of genomic selection (GS) for the first time around two key growth traits of Channa maculata, weight and total length, and optimized the marker screening strategy in combination with genome-wide association analysis (GWAS) (Cui et al., 2024). A total of 790 individuals were subjected to SNP typing in the study, and 45 695 high-quality SNPs were screened for GS model construction, with estimated trait heritabilities of 0.32 and 0.30, respectively. Among the four GS models, BayesA and GBLUP performed well, especially when the 3K SNP panel screened by GWAS was used, the accuracy of weight prediction increased by up to 94.59%. The results of the study show that in the process of snakehead domestication, the integration of GWAS and GS can achieve efficient and low-cost genetic improvement of growth traits. 6.2 Research on the application of probiotics inChanna breeding With the successful domestication of Channa sp., breeders have gradually incorporated it into the commercial breeding system. However, in the seedling stage, it often faces the problems of slow growth and low survival rate,
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