Effects of morphological traits on body mass of Procambarus clarlii at different ovarian maturity rates

【Objective】To determine the effects of morphological traits on body mass in Procambarus clarlii populations with different ovarian maturation rates,and to provide reference for P.clarlii selection and breeding.【Method】Obtained crayfish populations with different ovarian maturity rates by means of environmental stress in the sunfield,and measured 11 morphological traits such as total length(X₁),body length(X₂),cephalothoracic armour length (X₃) and body mass (Y) of the populations with different ovarian maturity rates;and investigated the relationship between the body mass of the P.clarlii populations with different ovarian maturity rates and the main morphological traits through the correlation analysis,pathway analysis and multiple regression analysis.【Result】Three populations of P.clarlii with different ovarian maturation rates51.67%(S₁+S₂),76.67%(S₃) and 96.67%(S₄)were identified by environmental stress in the sunfields.The results of correlation analysis showed that there were significant (P<0.05) or extremely significant (P<0.01) differences in each morphological trait and body mass among the populations with different ovarian maturation rates,and the coefficients of variation for body mass were all more than 25.00%,resulting in a high potential for selection and breeding.The results of the pathway analysis showed that the total coefficient of determination of the three ovarian maturity rate populations was≥0.850,51.67%ovarian maturity rate populations’body mass (Y) was jointly determined by the total length (X₁),chelicerae length (X₅) and total abdominal length (X₈);76.67%ovarian maturity rate popula-tions’body mass was jointly determined by cephalothoracic armor length (X₃),cephalothoracic armor width (X₄) and chelicerae length (X₆);96.67%ovarian maturity rate populations’body mass was jointly determined by the total length(X₁) and chela width (X₇).The multiple regression equations of morphological traits and body mass of the three ovarian maturity rates P.clarlii populations were as follows,Y_S1+S2=-34.028+0.301X₁+0.320X₅+0.256X₈；Y_S3=-34.142+0.645X₃+0.835X₄+0.261X₆；Y_S4=-45.899+0.553X₁+1.493X₇.【Conclusion】With the increase of sunning time,the ovarian maturation rate of P.clarlii increases,and when the ovarian maturation rate is 51.67%,the main morphological traits that signifi-cantly affect the body mass are chelicerae length,and the abdominal full length and the whole length as the supplementary ones.When the ovarian maturation rate increases to 76.67%,the main morphological traits that significantly affected body mass are cephalothoracic armor length,supplemented by cephalothoracic armor width and chelicerae length;when the ovarian maturation rate increases to 96.67%,the main morphological traits that significantly affected body mass are full length,supplemented by chelicerae width.