[Induction of polyploid in the Pacific abalone by caffeine-heat shock treatments]

Polyploid of Pacific abalone, Haliotis discus hannai Ino, was induced by blocking Polar body I with caffeine-heat shock treatments. Fertilized eggs were treated with caffeine concentrations at: 2.5 mmol/L, 5 mmol/L and 10 mmol/L; heat shock temperatures at 24 degrees C, 26 degrees C, 28 degrees C, lasting for 10 min to 30 min, total 5 periods of time, beginning at 10 min post-fertilization. Both fertilizing and incubating at 21 degrees C sea water. The results of studies showed that the effective procedure for inducing triploid appeared to be 5 mmol/L and 10 mmol/L Caffeine concentration, heat shock temperature 26 degrees C, duration 10 min to 15 min, all beginning at 10 min after insemination. The percentage of triploid was 64.6%-77.8%, Comprehensive efficiency index of polyploid induction was 0.57-0.61. Under the condition of 5 mmol/L caffeine concentration and the temperature 26 degrees C for 30 min duration at 10 min post-fertilization, 2.8%-3.6% tetraploid embryos could be produced.