Genetic Evaluation of Local Strain BRAJA 001 Tilapia Resulting from Crossbreeding (Kekar × Jatimbulan Strains)

Improving aquaculture productivity in Indonesia requires the development of locally adapted, high-performance tilapia strains, particularly for saline water environments. This study aimed to genetically evaluate a hybrid tilapia strain, namely BRAJA 001, derived from crossbreeding between the Kekar and Jatimbulan tilapia strains, using the mitochondrial cytochrome oxidase subunit I  (co1) gene as a molecular marker. A total of ten individuals were sampled, and co1 sequences were amplified, sequenced, and analyzed using BLAST, nucleotide composition profiling, phylogenetic tree reconstruction, and genetic distance estimation. BLAST results confirmed the identity of BRAJA 001 as Oreochromis niloticus with 100% similarity. Nucleotide composition showed a consistent base pattern (T: 28.9%, C: 29.8%, A: 24.4%, G: 16.9%) across BRAJA 001 and its parental strains, indicating mitochondrial stability. Phylogenetic analysis grouped BRAJA 001 with its parental lines and other O. niloticus populations from different regions, revealing high genetic similarity. Genetic distance values between BRAJA 001 and other Oreochromis species remained low (0.051–0.073), supporting its close relationship within the genus. These findings demonstrate that BRAJA 001 maintains genetic integrity while combining desirable traits from both parental strains, establishing a strong foundation for its further development as a superior, saline-tolerant local tilapia strain for sustainable aquaculture.