Path Analysis of Quantitative Characters for Mactra veneriformis with Different Ages in Geligang

Abstract

Mactra veneriformis is a common economic benthic shellfish with high nutritional value and is widely distributed in the Shandong and Liaoning provinces. Geligang is located in the northern part of Liaodong Bay. It is formed by the water impact of Shuangtaizi and Liaohe River. It has an area of approximately 10 000 hm2 with a fertile substrate. It is an important habitat of beach shellfish, such as M. veneriformis. Studies on the influencing factors of wild population quality traits and their correlation with morphological traits are helpful for developing genetic breeding of marine shellfish. To analyze the effects of morphological traits on quality traits of M. veneriformis at different ages in Geligang, the shell length (SL), shell width (SW), shell height (SH), body weight (BW), and soft tissue wet weight (RW) of 1–3 years old M. veneriformis were analyzed using correlation analysis, path analysis, and multiple regression analysis. The M. veneriformis used in the experiment was obtained from the Geliang in Liaodong Bay in September 2022. A total of 80 1-year-old, 104 2-year-old, and 168 3-year-old M. veneriformis were obtained. The results showed that the morphological traits of M. veneriformis at different growth stages had different contributions to quality traits, and there were significant differences (P 0.05) and was eliminated. The optimal regression equation of quantitative traits to qualitative traits of 1–3 year-old M. veneriformis was established. The results showed that when BW was the target trait, SW was the main selection trait and SL was the auxiliary selection trait for 1–3 year-old M. veneriformis. When RW was the target trait, SW should be the main selection trait for 1-year-old M. veneriformis, supplemented by SL. The SL should be the main selection trait for both 2- and 3-year-old M. veneriformis, but the SW was the auxiliary selection trait for 2-year-old M. veneriformis, while the SH was for 3-year-old M. veneriformis. In this study, correlation analysis, path analysis, and multiple regression analysis were performed on the morphological traits and quality traits of 1–3 years old M. veneriformis to determine the key morphological traits affecting the quality traits of M. veneriformis at different ages. In this study, the R2 values of the morphological traits of 1- and 2-year-old M. veneriformis (0.898 and 0.859, respectively) were greater than 0.850, indicating that the main factors affecting the body weight of living M. veneriformis were found. However, the R2 value of the morphological traits of 3-year-old M. veneriformis (0.815) was below 0.850, indicating that there may be other influencing traits in addition to the traits analyzed in this study. The reason may be that with the growth of M. veneriformis, the thickness of the shell and the effect on the weight of the living body gradually increase. In this study, the R2 values of morphological traits of 1–3 years old M. veneriformis (0.738, 0.648, and 0.538, respectively) on the wet weight of soft tissue were all below 0.850, indicating that there were other key factors affecting the wet weight of soft tissue. The age of sexual maturity of the M. veneriformis is at 1 year. The development of the gonad in the soft part may be closely related to the size of the wet weight of the soft tissue. The sampling period is mainly in the proliferation to depletion period of the gonad development of M. veneriformis. The gonad development is simultaneously affected by the environment. These results can provide reference for breeding M. veneriformis and the selection of parent shellfish.

Keywords

• mactra veneriformis
• morphological character
• path analysis
• correlation analysis