Two year classes of the Pacific oyster (Crassostrea gigas) from the Oyster Selection Breeding Program were compared. Oysters were harvested at 360 days of age in 2009 and in 2010 and comprised 24 and 32 full-sib families, respectively. All oysters in both year classes were reared under the same conditions. Shell height, shell length, shell width, total weight, shell weight, meat weight and meat ratio (100% × meat weight/total weight) were measured in 30 oysters from each family. Growth-related traits showed significant differences between the two year classes (P<0.05). There was a tendency for oysters sampled in 2009 to have lower shell heights, meat weights and meat ratios than in 2010, but their total weights were higher in 2009. Except for the meat ratio, there was a significant positive linear correlation between shell height and the other growth-related traits in both year classes (P<0.05). Shell height and total weight showed higher heritabilities: 0.35 ± 0.15 (SE) and 0.27 ±0.13, respectively. All phenotypic and genetic correlations between two growth-related traits were positive. There was also a difference in the degree of correlation between two traits. The use of growth-related traits in breeding programs designed to improve growth is discussed.%在长牡蛎( Crassostrea gigas)的选择育种工作中,于2009年和2010年分别获得24个和32个全同胞家系.根据长牡蛎360日龄的壳高、壳长、壳宽、总重、壳重、肉重和出肉率参数,利用ASREML软件的REML方法计算表型变量的方差组分,估算r长牡蛎成体阶段生长性状的遗传参数.结果表明,不同年份长牡蛎家系的生长存在显著差异,2009年家系的壳高、肉重和出肉率显著低于2010年家系(p＜0.05),2009年家系的总重则显著高于2010家系(P＜0.05).除出肉率外,2009年和2010年家系的壳高与其他生长性状均存在显著的正相关性(P＜0.05).壳高和总重具有较高的遗传力,分别为0.35±0.15和0.27±0.13.长牡蛎成体阶段各生长性状间的遗传相关和表型相关均为正相关,但相关性的大小不同.本研究估测的长牡蛎成体阶段生长性状的遗传参数,可以为合理制定长牡蛎的育种方案和选择反应预测提供参考依据.
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