Study On The F₄ , F₅ Generation Of Four Colors Of Pinctada Martensii Shell

According to the genetics theory and utilizing closed breeding methods of the group generation, this study focuses on the breeding and purifying the color of Pinctada martensii shell as well as selecting the economic characters (shell length, shell height, shell width, growth rate)of every shell color. Four shell color breeding categories——black shell color , white shell color, red shell color and yellow shell color was built after four generations. Compared the differences of parameters of the livability, growth rate and the economic characters between F₄ generation and groups of common culture, Investigated differences of survival rate and growth rate of the four Shell Color Line in different culture conditions, evaluated the environmental effects on the Line of survival and growth; took the four Shell Color Line F₄ as parents, cultivated 16 families by the diallel cross, studied in fertilization rate, hatching rate, survival rate, growth rate differences of every family and inheritance regular of the four shell colors.Findings are as following:1,Through the compared study of production performance between four Shell Color Line F₄ and the groups of common population, assess the progress of breeding and the differences of the performance among each breeding lines, provide a theoretical basis for the following generations of breeding results .as a result, the analysis of variance showed that there were significantly differences among the breeding lines as well as between the breeding lines and the general population on livability, the four Shell Color Line were higher than normal population. The differences among black, red and yellow shell are not marked and all much higher than the white ones, it shows the shell color is related with the livability in some degree. The height growth rate of the four color shell of the breeding lines is: white>black>yellow>=red>common groups. The height growth rate of the four color shell of the breeding lines is: white>black>yellow>=red>common groups.,The breeding line of white has the highest growth rate of shell length and height. The width growth rate of the four color shell of the breeding lines is: white>=black>yellow>=red>common groups. The weight growth rate of the four color shell of the breeding lines is: white>=black>red>=yellow>common groups.,the black and white shell ones have a better growth performance. 2,Through the compared study of parameter of the economic characters between the F₄ generations of breeding lines, evaluate the characters of each breeding lines, provide a theoretical basis for the future utilization of the hybrid vigor among the breeding lines. The result shows: the height parameters in order are : red> yellow>= black>= white> common group; the body weight parameters in order are: yellow> red> white>= common group> black; the shell weight parameters in order are: red= yellow> white> black >common group; the shell thickness parameter in order are: red> black>= yellow >=white >=common group; the red shell breeding line has not remarkable advantage in growth rate but largest parameters in shell width and shell thickness, which are the main characters in pearl breeding for cultivating large scale posterior layer pearls.3,Through the comparative analysis of the economic characters of the F₄ generations of the four shell color breeding lines in two different sea areas after 12 months cultivation, evaluate the environmental effect and provide a reference for the presentation of the excellent genetic characters of new lines and the choice of breeding environments. From the result, the F₄ generations of four shell color breeding lines in Maichen sea area of Xuwen are much better than the one in Liusha sea area of Haikang both in livability and growth rate (shell height).The former is 18.63% and 19.34% higher than the latter. It indicates that the Maichen sea area of Xuwen is mre suitable for the Pinctada martensii breeding than Liusha sea area of Haikang, and also indicates there are serious cultivation problems in the Liusha sea area of Haikang, there are need to strengthen the investigation of the sea environment, carry capacity assessment and disease control, and conduct deep-sea pearl research, to reduce pressure on coastal aquaculture to address the North Bay Pinctada martensii culture of sustainable development.4,Took the four Shell Color Line F₄ as parents, cultivated 16 families by the diallel hybridization, studied in fertilization rate, hatching rate, survival rate, growth rate differences of every family and inheritance regular of the four shell colors. The results show that, there is no difference among each families, the hatching rate is highest in group BB,RB,YY,WY,BY,BR, and is much different from other groups; the shell length, shell height, growth and survival rate are remarkably different in the early breeding period( first two months) on the sea, in survival rate, BR, RY are highest, WR,YB,BB are higher, RY,RW,YW,WB and BW are lower. In growth rate of shell length, BB,WB,YB,BW are highest ;in shell width, WB,BW,BY,YB,WW,BB,YW,YY,WY are largest; In growth rate of body weight, WB,WW,YW,YY,BB,WY,RY are largest, and with notable difference from other groups;each group has its advantage, RW,BR,WR,RR,YR,RB whose father or mother is red are lower in growth rate.5,Took the four shell color line F₄ as parents, studied the inheritance of the four shell colors by the diallel cross. The results show that, the inheritance of the four shell colors of Pinctada martensii are complex, from the hybridization of shell color it shows that the four shell colors are not remarkable allele, and they are not in a dominant or recessive relationship. from the self-breed of shell color it shows that the four shell colors are almost purification, the purification rate of the black, white, red and yellow are 97.5﹪,93.5﹪,99.5﹪,99.0﹪, from the bottom shell color of the filial generation of yellow, white, red and black shell color, yellow and white could be the shell bottom color, yellow is dominance when compare with white, the color analysis of the color areas shows: black is dominance when hybrid with red, and red shell color is paternal inheritance; white is maternal inheritance when hybrid with yellow; Yellow is paternal inheritance when hybrid with black.