Comparisons of growth and development of hybrid and backcrossing progenies between Crassostrea hongkongensis and Crassostrea ariakensis

Hybridization and backcrossing between Crassostrea hongkongensis and Crassostrea ariakensis were conducted in this study,and consequently,the experimental groups HH(C.hongkongensis),AA(C.ariakensis),HA(C.hongkongensis ♀×C.ariakensis ♂),AH(C.hongkongensis♂×C.ariakensis♀),HAHA(HA♀×HA♂),HHA(HH♀×HA♂),HAH(HA♀×HH♂),HAA(HA♀×AA♂),AHA(AH♀×AA♂)were produced using the method of diallel cross.The results showed that C.hongkongensis eggs can be fertilized by C.ariakensis sperm(47.33%±2.52%),but not vice versa.The fertilization can occur between HA and HH or AA.The fertilization rates of backcrossing groups were lower than those of inbred groups HH and AA.The hatching rates of the backcrossing between HA and AA were lower than those of the other groups,which were 20.33%±2.08%(AHA),55.67%±2.52%(HAA)respectively.The larval survival rate of the AHA and HAHA was 0;The survival of HA larvae was lower than HH and AA.The hybrid larvae grew faster than C.ariakensis larvae,but grew slower than C.hongkongensis.The survival rates of HA,HH,and AA juveniles were not significantly different(P0.05).The hybrid juveniles grew faster than C.hongkongensis larvae,but grew slower than C.ariakensis.In addition,the larval and juvenile growth of HHA and HA was not significantly different(P0.05).The larval survival rate was not significantly different in HHA and HA.The juvenile survival rate of HHA was lower than HA,but was higher than that of the other backcrossing groups.The results provide a basis for study on the hybridization and backcrossing between C.hongkongensis and C.ariakenis.