Correlation and Path Analysis of Phenotypic Traits in Different Geographical Groups of Manila Clam Ruditapes philippinarum

The shell length(SL), shell height(SH), shell width(SW), live body weight(mL), wet soft part weight(mM) and dry soft part weight(mF) were measured and their correlation coefficients analyzed among Manila clam Ruditapes philippinarum from southern group farming in the north(SN), northern indigenous group(NN) and southern indigenous group(SS) by correlation and path analysis to provide theoretical basis and measurement index for selection and breeding of Manila clam. It was found that the correlation coefficients between each shell morphological trait and mL or mM were all very significant in different geographical groups of Manila clam(P 0.05). The analysis of determinant coefficient showed that the main phenotypic traits affecting WM were not the same among different geographical groups, with the maximal direct effect of SW, and the secondary indirect effect of SW through SH in SN population;SL being the main factor through SH in NN population;the main direct effect of SH, and the indirect effect of SL through SH in SS population.The independent variables with inconspicuous test of the path coefficient were deleted, and the optimal regression equation of the mM of the clams was established by using the stepwise regression method: SN group mM1=-4.276+0.211SH+0.116SW;NN group mM2=-2.806+0.088SL+0.087SH;SS group mM3=-3.101+0.290SH.