| Oyster is delicious in meat and has extremely high nutritional value and economic value.It is an important marine aquaculture shellfish in coastal countries of the world.C.hongkongensis is the main economical cultured shellfish in China's oyster and even shellfish industries.C.ariakensis,C.angulata and C.hongkongensis belong to the giant oyster genus.The three are distributed in the southern coastal area of China with overlapping areas.To solve the problem of germplasm degradation of C.hongkongensis in recent years,high salt resistance is poor,mortality is high and the market demand,this research conducted on C.hongkongensis and near the C.ariakensis,C.angulate interspecific hybridization studies,in order to improve the quality of the C.hongkongensis germplasm and economic value.The results are as follows:(1)Firstly,the interspecific hybridization of C.hongkongensis(HH)and C.ariakensis(AA)was carried out using the gradient salinity method.The early table of the hybridization of the salinity(8,14,20 and 26)to the hybrid progeny was studied under the conditions of water temperature 28?32°C.Effects of type traits.The results showed that C.hongkongensis and C.ariakensis could only be fertilized in one direction,in the cleavage stage,the hybrid group had different degrees of heteros is(H > 0),the maximum heterosis was 22.52%.In the hatching stage,the hybrid group showed all significant heterosis(H > 0,hp <-1 or hp > 1)except the salinity 8,in terms of survival rate,the hybrid group showed survival advantages at salinity 20 and 26(H > 0),and the hybrid survival advantages were 17.03% and 30.46%,respectively.In terms of growth,the hybrid group always showed salinity conditions of 20 significant heterosis(H > 0,hp <-1 or hp > 1).Compared to the inbred group,the hybrid group showed certain growth and survival advantages,and had the characteristics of high salt tolerance.(2)In order to determine whether surviving hybrid progeny or even heterosis can be obtained in the case of distant hybridization,inter-species cross between C.hongkongensis(HH)and C.angulate(NN)was carried out using gradient salinity.The effects of salinity(8,14,20 and 26)on the early phenotypic traits of hybrid progeny were compared at a water temperature of 28?32°C.The results showed that: in the cleavage and hatching stage,the cleavage and hatching rate of hybrid larvae was much lower than that of the inbred group larvae,showing a significant hybrid disadvantage(H < 0,hp <-1 or hp > 1),in the growth and survival stage,the hybrid group in terms of growth rate and survival rate Compared with the inbred group,a heterosis was produced under a high-salt environment,especially at a salinity of 20,the heterosis was more significant(H > 0,hp <-1 or hp > 1).(3)Finally,in order to improve the germplasm quality,survival rate and growth rate of C.hongkongensis,interspecies hybridization experiments of C.hongkongensis with C.ariakensis and C.angulata under different salinities(8,14,20 and 26)were carried out.The results showed that in this experiment,during the cleavage and hatching stage,the cleavage rate and hatching rate of the hybrids of C.hongkongensis ? × C.ariakensis ? were significantly higher than those of C.hongkongensis ? × C.angulata ?(P < 0.05).In terms of survival rate and growth,the suitable growth salinity of the hybrids of C.hongkongensis ? × C.angulata ? is 20-26,which is a significant increase in tolerance of high-salinity compared to C.hongkongensis(14-20)(P < 0.05).In terms of growth rate,the two hybrid progeny produced a lot of eye spots around 16 days,but the shell height is C.hongkongensis? × C.ariakensis? hybrid is significantly longer than C.hongkongensis? × C.angulata? hybrid(P < 0.05).It provided a direction for the cross breeding of C.hongkongensis. |
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