Tetraploidy induced by heat shocks in the rainbow trout (Salmo gairdneri R.).

In this study, I attempted to induce tetraploidy in the rainbow trout by means of 28 degrees C-heat shocks applied to fertilized eggs. Variations in the parameters of treatment resulted in large differences in survival rates between the batches, and varying proportions of tetraploid, diplotetraploid and diploid embryos were obtained with shocks beginning between 6 h 30 min and 9 h after fertilization and lasting more than 14 min. Tetraploidy was always associated with high mortality rates.