Induction of triploidy in Puntius Gonionotus (Bleeker) by cold shock

Abstract

The experiment on induction of triploidy in Puntius gonionotus was done by using cold shock technique. Eggs stripped from 2 females were fertilized with sperm from defferent males and subsequently dipped in cold water (15^oC) at 0 and 5 minutes after fertilization with shock durations of 15 and 30 minutes. It was revealed that only cold shock at 0 minute after fertilization with shock durations of 15 and 30 minutes produced triploid fry with the average percentages of 95.45 and 90.45 respectively. Their average hatching rates decreased considerably to 4.96 and 33.87% as well as survival rates which were 46.53 and 16.01% respective to shock durations of 15 and 30 minutes. At maturity gonads of triploid fish tremendously reduced in size when compared with their diploid counterpart. Histological study showed few previtellogenic oocytes and spermatozoa in ovaries and testes respectively.