Induction of Triploidy in Indian Edible Oyster Crassostrea madrasensis (Preston) Using 6-Dimethylaminopurine

Abstract

Triploidy was induced in the Indian edible oyster Crassostrea madrasensis, by treating the newly fertilized eggs with 6-Dimethylaminopurine.The effect of different concentrations and durations of treatment on triploidy induction and survival of embryos were examined. The optimum condition was found to be 100 μM concentration of 6-DMAP for 8 minutes when 50% of the freshly fertilized eggs have extruded the first polar bodies. This yielded 67±1.7 % of triploid on the first day and 62±1.5% on the D-stage larvae as determined by examination of the metaphase chromosomes. Survivability among the different treatment groups at D stage were not significantly different. This is the first demonstration of induction of triploidy in Crassostrea madrasensis using 6-DMAP and since edible oyster farming is becoming increasingly popular in India, application of this technique in the production of culture stock assumes importance.