| Summary: | Gynogenesis is a chromosome set manipulation technique to accelerate inbred lines used for genomics analysis and genetic breeding. Groupers are hermaphroditic fish whereby they sexually mature as females and subsequently change sex to male. Production of the homozygous inbred lines of groupers will take a prolonged period with the traditional method. This study presents the meiotic gynogenesis induction of the commercially cultured grouper Epinephelus fuscoguttatus, using a combination of ultraviolet-irradiated heterogenous sperm of E. lanceolatus and recovering second polar body by cold-shock treatment. DNA ploidy verification by flow cytometry showed that the haploid larvae exhibited abnormalities and diploids developed normally. The results indicated that UV irradiation doses at 150 mJ/cm2 produced 100% haploid larvae. The high percentage (52.1% ± 8.50%) of gynogenetic diploidy was induced by cold shock at 5–7 °C for 10 min, initiated 6 min after fertilization. The gynogenetic offspring presented 48 chromosomes (2n = 48t) and were morphologically identical to maternal chromosomes. Cytological and morphological evidence suggested that gynogenetic individuals were successfully obtained. Histological examination revealed that the gynogens gonads could develop into ovaries. Summarily, the gynogenesis technique was very representative of creating inbred lines in groupers. The successful production of this inbred lines is of great significance in grouper genetic breeding and genomic analysis.
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