壳白长牡蛎家系幼体生长存活比较及生长性状遗传参数评估

GENETIC PARAMETERS AND GROWTH TRAITS IN WHITE SHELL FAMILIES OF PACIFIC OYSTER (CRASSOSTREA GIGAS)

  • 摘要: 研究以经过连续7代人工选育壳白长牡蛎品系为素材, 通过巢式设计, 成功构建了12个半同胞家系和29个全同胞家系, 同时以未经选育的个体子代为对照组, 评估了各家系和对照组幼体在不同日龄下的生长和存活差异。结果显示, 不同日龄, 壳白长牡蛎家系幼体生长和存活率均高于对照组, 壳高和存活率分别提高3.65%—14.58%和1.11%—19.26%; 生长和存活性状在不同壳白家系间差异显著(P<0.05), 其中G11、G15和G35家系在生长和存活率方面均有较大优势, 在19日龄, 与壳白家系平均值相比, 其壳高的累积生长量分别增加11.87%、17.03%和30.32%, 存活率分别提高38.35%、33.41%和51.07%; 与对照组相比, 其壳高的累积生长量分别增加34.09%、28.18%和49.31%, 存活率分别提高65.00%、59.11%和80.18%。同时对壳白长牡蛎幼体壳高和壳长的遗传参数进行了评估。壳白长牡蛎幼体壳高和壳长的遗传力变化范围分别为0.28—0.81、0.42—0.88, 均属于中高遗传力; 壳白长牡蛎幼体不同日龄壳高和壳长的遗传相关和表型相关均为正相关, 相关系数的范围分别为0.35—0.81、0.57—0.85。研究为培育生长性能优良和存活率高的壳白长牡蛎品系提供了基础资料。

     

    Abstract: Pacific oysters (Crassostrea gigas), the most widely cultivated shellfish over the world with advantages of fast growth and strong environmental adaption, are suitable materials for selective breeding due to the characters of high fertility, short reproductive cycle and large genetic variation. Broodstocks from white shell strain of C. gigas that had undergone four-generation family selection and three-generation mass selection were used to establish 29 full-sib families and 12 half-sib families by nested design. Random selected individuals were utilized as parents to generate the control families. Phenotypic traits such as growth and survival rate of different periods in larval stage were analyzed. Results showed that the growth performance and average survival rates of white shell families were significantly higher than those of control group with the augmentation of 3.65% to 14.58% and 1.11% to 19.26% in a family dependent pattern, respectively. The G11, G15 and G35 families represented remarkable superiorities in shell height and survival rates. At the age of 19 days, the increased shell heights of G11, G15 and G35 families were bigger than the average values of white shell families by 11.87%, 17.03%, and 30.32%, respectively, and were greater than the average values of the control by 34.09%, 28.18%, and 49.31%, respectively. Besides, the survival rates of G11, G15 and G35 families at 19d were higher than the average values of both white shell by 38.35%, 33.41%, 51.07%, and control families by 65.00%, 59.11%, and 80.18% (G35), respectively. Results of genetic parameters of larvae shell height and shell length of white shell strain indicated that the variation of heritability was ranged from 0.28 to 0.81 in shell height and from 0.42 to 0.88 in shell length, representing the heritability at medium to high level. The genetic and phenotypic correlations were positive between the two growth traits with the correlation coefficients ranging from 0.35 to 0.81 and from 0.57 to 0.85, respectively. This study provides optimum breeding strategy for white shell strains ofC. gigas to improve performance in growth and survival.

     

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