COMPARISONS OF THREE TRIPLOID INDUCTION METHODS IN CRASSOSTREA SIKAMEA

To obtain an efficient C. sikamea triploid induction scheme, we compared 6-DMAP, low salinity and high salinity on C. sikamea triploid induction in terms of cleavage rate, hatching rate and triploid rate. The effects of different concentrations (salinity), initial induction times and induction duration were also studied. At the same time, the growth, survival rate and triploid rate of larvae obtained by the three methods were compared. In the 6-DMAP induction group, the triploid rate and induction efficiency reached 37.97%—58.01% and 34.30%—42.50%, respectively; during the cultivation period, the average survival rate of larvae was 27.19%, the growth rate was 13.03 μm/d, and the triploid rate reduced by 24.94%. In the low-salt induction group, the triploid rate and induction efficiency reached 7.32%—42.25% and 2.17%—31.41%, respectively; during the cultivation period, the average survival rate of larvae was 33.92%, the growth rate was 12.71 μm/d, and the triploid rate reduced 20.64%. In the high-salt induction group, the triploid rate and induction efficiency reached 7.47%—63.03% and 6.58%—49.41%, respectively; during the cultivation period, the average survival rate of larvae was 31.66%, the growth rate was 13.08 μm/d, and the triploid rate was reduced by 17.64%. In general, high salinity induction is the best triploid induction method for C. sikamea, and the optimal induction condition was induced for 20min start at 15min post fertilization using 55 salinity water. This study provides technical support for C. sikamea triploid induction and has important theoretical guiding significance for polyploid breeding of C. sikamea.