Productive Traits and Triploid Rate Stability in Triploidy-Induced 'Haida No. 2' Strain of the Pacific Oyster, Crassostrea gigas

In order to evaluate the effects of triploidy induction on a selected strain 'Haida No. 2' of the Pacific oyster Crassostrea gigas, which is characterized with golden shell color and high growth rate, the growth, survival rate and stability of triploid rate were analyzed at different development stages in the present study. Three different conditions inhibiting the release of polar body II or polar body I were tested: (A) Cytochalasin-B (CB), 0.5 mg L-1 at 10 min post-insemination for 15 min; (B) CB, 0.5 mg L(-1)at 15 min post-insemination for 20 min; and (C) CB, 0.7 mg L-1, at 15 min post-insemination for 20 min. The triploidy induction treatments significantly reduced the D-larvae and survival rates at the larvae stage but not at the juvenile and adult stages. Triploid rate dramatically decreased at the larval stage and did not significantly change at the juvenile and adult stages. Regarding the stability of the triploid rate, there was a significant difference between the three treatment groups. Larvae from the treatment A and control groups exhibited higher growth rates in shell height than those from the other two treatment groups at day 27. Triploid juveniles and adults from the treatment A group exhibited a higher wet weight than diploids from the control group and triploids from the other treatment groups. Triploidy induction did not affect the shell color of the progeny. The results obtained in the study demonstrate that triploidy induction has the potential to be used to increase the production of C. gigas variety 'Haida No. 2' without modifying its golden shell color.