A study on thick pearls produced by the third generation shell color lines of pearl oyster(Pinctada martensii)

Two experiments were designed to evaluate the pearl production traits of the third generation red(RS3),yellow(YS3),white(WS3)and black(BS3)shell colored lines.Different colored lines were used as host and donor oysters respectively.The pearl in Experiment Ⅰ,16 combinations were established by sampling the RS3,YS3,WS3 and BS3 lines as honor and donor oysters.Another combination was established by using the common cultured stock and YS3 as honor and donor oysters,respectively.And a total of seventeen combinations were established.The pearls were harvested after the honor oysters were cultured for twenty-four months.In Experiment Ⅱ,sixteen combinations were established by sampling the RS3,YS3,WS3 and BS3 lines as honor and donor oysters.The pearls were harvested after the honor oysters were cultured for eighteen months.After harvesting pearls,shell height growth and survival of the RS3,YS3,WS3 and BS3 lines were compared in both experiments.Retention rate,commercial pearl rate,better quality pearl rate and pearl thickness of each combination in Experiment Ⅰ and Ⅱ were compared.The results showed that there existed significant differences in mean shell height and survival among the RS3,YS3,WS3 and BS3 lines in Experiment Ⅰ and Ⅱ(P0.05).The BS3 line had the largest mean shell height compared with the RS3,YS3 and WS3 lines in Experiment Ⅰ and Ⅱ.The YS3 line had the largest survival in Experiment Ⅰ and the BS3 line had the largest survival in Experiment Ⅱ.In Experiment Ⅰ,there were significant differences in retention rate,commercial rate,perfect quality pearl rate and pearl performance values among the 17 combinations(P0.05);There were insignificant differences in pearl thickness among the 17 combinations(P0.05);The BW combination had the highest retention rate,commercial pearl rate,pearl thickness and pearl performance value,and the RB had the highest perfect quality pearl rate.In Experiment Ⅱ,there were significant differences in retention rate,commercial rate,pearl thickness,perfect quality pearl rate and pearl performance values among the 16 combinations(P0.05).A combined analysis on host or donor oysters showed that the BS3 line is desirable for host oyster to produce better quality pearl and is promising in the commercial pearl production.