The study on phenotypic traits of different shell color strains F₁ and F₂ (C:the control strains; Tr; twoband red strain; Tw:twoband white strain; Ab:agateblack strain; Or:oceanred strain; Pw:pearlwhite strain; Z:zebra strain; W:wave strain.)of Manila clam was conducted in September 2007.The results showed that the shell length of Pw F₁ was the greatet,and significantly greater than others except Tr (P<0.05),the shell length of Z was the smallest,and significantly smaller than others(P<0.05),there were no obvious differences in shell length among C,Or,W,between Tr and Tw,among Tw,Ab,Or,among Ab,Or,W(P<0.05).Both fresh weight and fecundity of Pw F1 were the greatet,that of Tr were the second greatet and significantly greater than others(P<0.05),those of Z were the smallest,and significantly smaller than others(P<0.05),there were no remarkable differences between C and W,among Tw,Ab,Or in fresh weight and between C and Z,among Tr,Ab,Or,W in fecundity(P<0.05).No significant differences in eggdiameter,the fertilized rates and size of D larvae were observed among all strains(P<0.05),the hatching rate of C was significantly lower than those of other strains except Tw(P<0.05).By end of pelagic period(9 d),the shell lengths of W and Z were significantly greater than those of other strains(P<0.05),there were no remarkable differences in shell length among Tw,Ab,Or,Pw,Z,W(P>0.05); the sequences of survival rates were following:Ab,Z>Or,W>Tw,Pw>Tr>C,there were significant differences among them(P<0.05).No remarkable difference in both metamorphic time and metamorphic size among all strains was observed(P >0.05).There were such a sequence in metamorphic rates as follows:Ab>Z>Tw >Or>Pw>W>Tr>C,there were significant differences among them(P<0.05).By the end of indoor rearing period(240 d),the shell length of Ab were significantly greater than those of other strains except Or,Tr(P<0.05),the shell length of Z were significantly smaller than those of other strains except C,W(P<0.05),there were no remarkable differences in shell length between C and Pw,W,Tr,Tw,Or,and between Tw and Pw; the survival rate of Z was remarkably higher than those of other strains except Ab(P<0.05),the survival rate of C was remarkably lower than those of other strains except Tr,Tw(P<0.05).On day 360,both shell length and fresh weight were the greatet and remarkably greater than those of other strains(P<0.05),the shell length of Ab and Z were significantly smaller than those of other strains(P<0.05),the survival rate of Ab and Z were significantly higher than those of other strains except Or,Pw(P<0.05),the survival rate of Or was significantly higher than that of C(P<0.05),there was no remarkable difference in survival rate among other strains(P<0.05).The order of relative yields was as follows:Z(678.63%±56.80%)>Ab(554.88%±69.42%)>Or(527.23%±76.21%)>W(475.97%±90.25%)>Pw(405.90%±55.19%)>Tw(224.89%±47.85%)>Tr(178.50%±34.50%)>C(100.00%±22.10%).