Correlation And Path Analysis Of Major Quantitative Traits Of Winged Pearl Oyster, Pteria Penguin Before And After Cutting Off The Black Periostracum Edge

Based on the observation, winged pearl oyster, Pteria penguin changed greatly in morphology, while the shell without black periostracum edge probably had less changing.In order to make better research about the growth and nacre color formation of P. penguin,we measured 300 randomly chosen individuals with 6 morphological traits [shell height(SH), shell length (SL), shell width (SW), maximum diagonal length(MDL), hinge length(HL), byssus diameter(BD)]and 3 weight traits [total weight(TW), left shell weight(LSW),right shell weight(RSW)] to investigate the correlation of growth parameters of P. penguin(normal group and cut off black periostracum edge group). After cutting off the black shell periostracum edge, we measured 10 morphological traits and 1 weight trait. All the morphological traits were measured by taking pictures and using photoshop 2016 on the computer except BD (by vernier caliper) and weight traits (by electronic balance). The correlation coefficientand path coefficient were estimated by path analysis via SPSS 19.The result showed that①The shell peak made a vertical line to a plane and the pedal point T was exactly on the DVM line. The CT/CM trend line R2=0.0533, which concluded that CT/CM might be a fixed value as 0.34 ±0.025 and the value wouldn’t change as the shell length changed.② The angle of MDL and hinge(R1) is 37.42°± 3.55°,whose value was relatively stable, did not vary with the SH(Trend line R2 =0.0188). The angle of DVM(CM) and hinge(R2) is 42.61°±3.25°,whose value was relatively stable,had a similar result with SH and R1 (line R2 =0.0099). But an interesting result showed that the trend line of R1 and R2 was y=-0.6186x+65.53, R2=0.3857, which included R1 related very closely with R2. As the shellfish grew up, most observed traits increased as SH and total weight changed, while we paid less concern on any fixed values among the living process. Therefore, we could make a preliminary view that R1, R2 and CT/CM could describe a special shape of P. penguin and were also important labels that separated from other shellfish species.③The correlation coefficient of the shell without periostracum edge was higher than normal shell, which concluded that morphological traits of the shell without periostracum edge changed more regularly, had better research significance and value.④There were significant correlation among most quantitative traits except BD and R1 .The multiple regression equation of right shell weight (X18),SH (Xi) and SL (X2) to the TW was built to estimate TW(Yi),Yi= -88.969+2.629X18+8.321Xi+15.3X2. This work shall provide a theoretical method to measure P. penguin for breeding purposes. The result provided important reference for the selective breeding of P. penguin.