ARTICLE
P > 0.05). As shown in Table 3, the phenotypic and genetic correlation between BW and BL were as high as 0.9408 ± 0.0040 and 0.9562 ± 0.0551, respectively, which were significantly different from zero (P < 0.01). These results indicated that growth traits (BW and BL) were highly correlated. Genetic parameters of cold tolerance, namely TAD and CDH, are shown in Table 2. The estimates of heritability for TAD and CDH were 0.265 ± 0.091 (P < 0.01) and 0.077 ± 0.058, respectively. There was no significant difference between CDH and TAD (Z = 1.74, P > 0.05). Correlation analysis indicated the phenotypic correlation between TAD and CDH was -0.5470 ± 0.0174, and the genetic correlation was -0.6707 ± 0.3635 (Table 3).
Genetic and phenotypic correlations between growth traits (BW and BL) and cold tolerance traits (TAD and CDH) are shown in Table 3. Phenotypic correlation coefficients ranged from -0.1055 to 0.1098. Phenotypic correlation coefficients between growth traits (BW and BL) and cold tolerance traits (TAD and CDH) were low. The genetic correlation coefficients between growth traits and TAD were low also, whereas the genetic correlation coefficients between growth-related traits and CDH were comparatively high. The genetic correlation coefficient between BL and CDH was the highest (0.9914 ± 0.7010), while the genetic correlation coefficient between BL and TAD was the lowest (-0.0526 ± 0.4664). In this study, the phenotypic and genetic correlation
coefficients between growth and cold tolerance traits of F. chinensis had a wide floating range.
Discussion Results showed that heritabilities for body weight and body length of F. chinensis juveniles were low (0.078 ± 0.124 and 0.131 ± 0.133, respectively). This agreed with those of body weight of shrimp at 150 days, as estimated by means of intra group correlation of full-sibs in prior research, whereas it was lower than the heritability of body length (0.36 ~ 0.51). Heritabilities for growth traits obtained in prior studies were higher than those obtained in this study. Several reasons may account for the results. First, heritability estimates are affected by different varieties or by different growth pe-
The coefficient variation of body weight was the greatest (59.919%), indicating that there was great variance in body weight between different families, while the coefficient of variation of body length was the smallest (18.226%), indicating that there was comparatively small variance in body length between different families.”
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