Study On The Improvement Of The Strains Of Shell Color And Shell Shape In R. Philippinarum For Different Generations

Study on the improvement of the strains of shell color and shell shape in R. philippinarum for different generations was conducted, the main results are as follows:1. Control of growth and development between Zebra and orange strain nested- diallel families48 nested diallel hybrid families between zebra calm and orange strain of Raditapes philippinarum were established. The results showed that fertilized rates were a little different among each family with a mean of 90%. The hatching rate was significantly different between selfing group and hybrid group. The hatching rate level of hybrid group was higher than selfing group. The average SGR of planktonic larvae and juvenile stage were 2.20% and 5.08%. The distribution of shell length and height were in line with the typical normal distribution. The highest metamorphosis rate of these families was（58.26±0.98） %（p<0.05）. The sequence of average survival rate（ASGR） was ASROZ>ASRZO >ASROO>ASRZZ.Analysis on the effects of egg original（EO） and mating strategy（MS） showed that the interaction of EO and MS had a significant effect on shell growth during planktonic stage（5-15 day）. The main influence was from EO in juvenile stage（30-60 day）, while hatching rate was influenced by EO significantly（p<0.05） and there was not significant influence caused by the interaction or MS on hatching rate（p<0.05）. The interaction or MS significantly influenced the metamorphosis rate and survival rate. Overall, the growth performance of hybrid group was better than selfing group. 2. Establishment of zebra clam core selection families15 nested zebra families were built as the core selection families in our experiment. Families were used to analyze the heritability. Results showed that hatching rate, metamorphosis rate and survival rate of family were significantly different（p<0.05）. The lowest hatching rate was 61.16±1.17%, average metamorphosis rate interval（11.24 ± 0.87） % ^{59.88 ± 0.14} % and the average family survival interval（16.50 ± 1.44） % ^{68.06 ± 1.12} %. The relationship between hatching rate and metamorphosis rate or survival rate was negatively correlated. The results of correlation analysis showed that metamorphosis and survival rate were significantly positively correlated（p<0.01）, the Pearson correlation coefficient was 0.928. The relationship between shell length and shell heigth AG was also positively correlated, the Pearson correlation coefficient was 0.937. 3. The family selection of width shell clamWe established 9 families for selecting wide shell calm strain by using width shell clam “F1”. The results showed that the highest and lowest fertilized rate was（93.13±0.56） % and（89.91±1.59） %. The average SGR was 4.16±0.25% and family A2 had the highest SGR（4.58±0.23） % in planktonic stage. The sequence of maternal average SGR was SGRC<SGRB<SGRA in planktonic stage. The sequence of maternal average SGR was SGRC<SGRB<SGRA in juvenile stage. Metamorphosis and metamorphosis time was positively correlated, metamorphosis and survival rate was also positively correlated. 4. Selection and breeding of fast-growing strainThe calms used in this experiment were selected from the calm population which was moved from south china and be cultured in north china. We filtered out two fast growing lines（FGL） by the size and height, named as long shell group（LS） and heavy class（HC）. The surface data of broodstock met the normal distribution tested by SPSS Kolmogorov-Smirnov. Seed rate were 2.86%（LS） and 9.52%（HC）. After domestication, the increase value（IV） showed that the IVHC was significantly larger than other grups（p<0.05）, and the shell length of IVLS was larger than other grups. The hatching rate, metamorphosis rate and survival rate of CG were significantly higher than the two FGL group（p<0.05）, and there was no significantly different between the two FGL group.Analysis on the selection reaction and heritability showed that the shell length of CG was larger than the ther groups（3-9 day）, while the shell length of LS and HC grew fast during juvenile stage and the growth dvantage showing gradually（40 day）.