Effects of Shell Shape Traits on Body Weight of Crassostrea angulata Diploid and Triploid at Different Months of Age

The effects of shell shape traits on body weight of diploid and triploid populations of Crassostrea angulata at 18 and 27 months of age were studied. The relationship between shell shape traits and body weight was clarified, which provided basic data for artificial breeding of polyploid oysters. A total of 50 individuals of diploid and triploid populations of Crassostrea angulata at 18 and 27 months of age were randomly selected to measure the four quantitative traits of shell height (SH), shell length (SL), shell width (SW) and body weight (TW), respectively. Then, the correlation analysis, multiple regression analysis, path analysis and determination coefficient analysis were used to analyze the effect of shell shape traits on body weight. The results of correlation analysis showed that the correlation coefficient between shell height and body weight of 18-month-old diploid and 27-month-old triploid populations of Crassostrea angulata was the largest, while the correlation coefficient between shell width and body weight of 18-month-old triploid and 27-month-old diploid populations of Crassostrea angulata was the largest. The results of path analysis showed that shell height was the main factor affecting body weight in the 18-month-old diploid and triploid populations, while shell width was the main factor in the 27-month-old diploid population, and shell height was the main factor in the 27-month-old triploid population. The result of coefficient of determination analysis was consistent with the result of the path analysis. According to the results of multiple regression analysis, four optimal regression equations of shell shape traits on body weight were established, and their correlation index R² was less than 0.850, indicating that there might be other factors that had a greater impact on body weight.