GENETIC-STUDIES WITH TENCH, TINCA-TINCA L - INDUCED MEIOTIC GYNOGENESIS AND SEX REVERSAL

Carp sperm with genome inactivated by gamma irradiation (Co-60; 1400 G Y dose) was used to induce gynogenetic development in tench (Tinca tin ca). The non-participation of paternal genome in tench female X carp m ale ''hybrid'' diploidized with cold shock was confirmed morphological ly, karyologically and biochemically. Consistent yields of 5-21% viabl e gynogenetic fry were obtained when eggs were incubated at 20 degrees C and cold-shocked (30 min at 0 to + 2 degrees C) 2, 5 (P < 0.1) and 10 min (P < 0.05) after gamete activation. When expressed in terms of tau(0) (duration of one mitotic cycle of synchronous cell division rel ated to water temperature) times after activation were 0.069, 0.173 an d 0.346 tau(0), respectively. In a preliminary study of sex reversal, sex was reversed with tench. The greatest effect of treatment appears to lie in the range of a 0.102 g/kg dose of 17 alpha-methyltestosteron e (MT) starting at 40-60 days after activation.