Objective The study was carried out to explore the morphological differences among three Paphia textile populations, which was of great importance for germplasma resources conservation, geographical populations identification and artificial breeding of P. textile populations along the coast of Beibu Gulf.

Method Based on 5 multivariate analysis methods(morphological characteristics analysis, variance analysis, principal component analysis, discriminant analysis and cluster analysis) were used to compare and analyze the morphological differences among three wild populations of P.textile in Beihai, Zhanjiang and Dongxing.

Result The Beihai population in Guangxi had the most round shell, thicker shell and fuller soft part. The average shell height coefficient was 0.585, shell thickness coefficient was 0.033, shell weight coefficient was 0.388, and soft part weight coefficient was 0.134. The Dongxing population in Guangxi had thin and light shell with the flattest shell type. The average shell height coefficient was 0.571, shell thickness coefficient was 0.032, and shell weight coefficient was 0.135. The Zhanjiang population in Guangdong had thick shell with the lowest shell uplift degree.The shell width coefficient was 0.366, shell thickness coefficient was 0.035, and shell weight coefficient was 0.325. Three principal components were obtained by the principal component analysis method, the contribution rates of principal component 1, principal component 2 and principal component 3 were 37.366 22.205% and 12.718%, respectively; and the cumulative contribution rate was 72.289%. Then, the discrimination functions of the 3 populations were set up, the identification accuracy was 94.00%-100.00%(P₁) and 92.11%-100.00%(P₂) and the total discriminate accuracy was 97.56%. The results of cluster analysis indicated that the morphological characteristics of Zhanjiang population were similar to those of Beihai population, but quite different from those of Dongxing population. In addition, Dongxing population had the highest degree of divergence.

Conclusion Compared with the Beihai population in Guangxi and the Zhanjiang population in Guangdong, the Dongxing population in Guangxi has the largest differences in morphology, and among individuals within the population, while the morphology of the Beihai population in Guangxi is more similar to that of the Zhanjiang population in Guangdong.