Meiotic gynogenesis inducing in Caspian Sea salmon (Salmo trutta caspius) using gamma irradiation followed by sex determination using SDY gene

Caspian Sea salmon (Salmo trutta caspius) is a valuable fish species in the Caspian Sea and its surrounding basin, which is considered as a suitable species in our country's fishing industry. Caspian salmon ovums and sperms were extracted from Caspian salmon. To perform gynogenesis, the sperms were irradiated with a gamma ray (60Co) at doses of 450, 600, 750, 900, and 1050 Gy. In the next stage, fertilization was performed by mixing the ovum and the irradiated sperm. To induce ploidy, a water bath with a temperature of 26-28 ˚C was established. The tail fins of different treatments were sampled and the DNA was extracted and its sex was determined using primers E1S1 and E2AS4 related to SDY gene. After salmon reached the appropriate weight, its sex was studied using classical histology. The results showed that in the 900 g group of fertilization, the survival larval was significantly higher than other gynogen groups (p < 0.05). Gender determination using molecular methods showed that in the treatment of female with a dose of 450 Gy, there is still one male determined. (1 sample out of 5 samples), this happened in a case that there was no male in other doses. But in all histological samples, there is no sign of male gonad. According to these results, it can be concluded that the gynogenesis of Caspian Sea salmon has been done successfully using this gamma irradiation method and a dose of 900 Gy is recommended as a suitable dose for using this method in this species.