KARAKTERISTIK FENOTIPE DAN GENOTIPE IKAN GURAMI, Osphronemus goramy, STRAIN GALUNGGUNG HITAM, GALUNGGUNG PUTIH, DAN HIBRIDANYA

Abstract

Persilangan antara dua populasi yang berbeda secara genetik lazimnya menghasilkan kombinasi genetik baru. Penelitian ini dilakukan untuk mengevaluasi karakteristik fenotipe dan genotipe ikan gurami strain Galunggung Hitam, Galunggung Putih, dan Hibridanya. Perkawinan dalam galur (GP X GP dan GH X GH) dan persilangan dua arah antara betina GH dan jantan GP (GH X GP), dan resiprokalnya (GP X GH) telah dilakukan di BPBIGN Singaparna. Fenotipe dianalisis berdasarkan metode truss morfometrik dan meristik, sedangkan karakteristik genotipe diamati menggunakan metode PCR-RAPD. Hasil analisis menunjukkan berdasarkan 21 karakter truss morfometrik, centroid hibrida GH X GP lebih tinggi dari centroid ketiga populasi lainnya pada PC-1 yang dicirikan oleh karakter B3, B4, B5, A3, A4, dan A6, dan bersifat intermediate pada PC-2, PC-3, dan PC-4. Berdasarkan delapan karakter meristik, centroid hibrida GH X GP lebih tinggi dari kedua tetua dan hibrida GP X GH pada PC-1 yang dicirikan oleh karakter SPR dan SDA, lebih rendah dari kedua tetua, tetapi lebih tinggi dari populasi GP X GH pada PC-2, dan lebih rendah dari ketiga populasi lainnya pada PC-3 dan PC-4. Polimorfisme dan heterozigositas pada populasi hibrida GH X GP dan GP X GH lebih tinggi daripada kedua tetuanya GH X GH dan GP X GP. Hibridisasi yang dilakukan meningkatkan variasi genetik yang dapat berguna dalam peningkatan produktivitas budidaya.

Hybridization between two genetically different populations is expected to generate a population carrying new genetic combinations which may be expressed in both phenotypes and genotypes. This study was carried out to explore the phenotype and genotype characteristics of reciprocal hybrids of goramy of Galunggung black (GH) and Galunggung white (GP) with respect to their parental lines. Matings within the same line producing GP X GP and GH X GH, and reciprocal mating producing hybrids GH X GP and GP X GH, were conducted at BPBIGN Singaparna. Samples representing the four populations were analyzed for their morphology using truss morphometric and meristic methods, while genotypes were analyzed using PCR-RAPD method. The results showed that based on the 21 morphometric characters, the centroid of hybrid GH X GP was higher than those of the other three populations at PC-1, which was marked by the characters B3, B4, B5,A3, A4, and A6, and was intermediate at PC-2, PC-3, and PC-4. Based on the eight meristic characters, the centroid of GH X GP was also higher than those of their parents and hybrids GP X GH at PC-1, which was marked by the characters SPR and SDA, lower than those of their parents but higher than that of hybrid GP X GH at PC-2, and lower than those of the other three populations at PC-3 and PC-4. The genetic diversities in terms of polymorphism and heterozygosity levels in hybrids GH X GP and GP X GH were higher than those found in the pure-line (GH X GH and GP X GP). Hybridization conducted in this study had resulted in the enhancement of genetic variations which could be useful in increasing aquaculture productivity.