A comparison of communal and separate rearing of families in selective breeding of common carp (Cyprinus carpio): Estimation of genetic parameters

The objective of this study was to investigate ways of improving the selective breeding program for growth related traits in common carp in Vietnam. A base population was established from six carp stocks following a single pair mating scheme. In the next two selected generations (G1 and G2) a total of 135 full-sib families were produced in G1 (107 selection families, produced by 58 sires and 58 dams using a partial factorial mating scheme; and 28 control families, using a single pair mating scheme) and 93 full-sib families produced in G2 (77 selection families, produced by 33 sires and 40 dams using a partial factorial mating scheme; and 16 control families, using a single pair mating scheme). Each family in G1 and G2 was split and reared using communal early rearing (CER) or separate early rearing (SER) methods. Seven microsatellite loci were used for parentage assignment in the CER groups: 96.8% of the offspring (1284 individuals) and 96.2% offspring (1342 individuals) were unambiguously assigned to 113 families in the G1 and 92 families in the G2 generations, respectively. Restricted maximum likelihood was used to estimate genetic parameters. The estimated heritability values were 0.25 for both weight and length at final harvest using CER. Higher heritability estimates were obtained in the SER groups, ranging from 0.29 for length to 0.32 for weight at final measurement. The maternal and common environmental effects were consistently close to zero in CER, whereas they ranged from 0.11 to 0.30 in SER. Note that CER conditions are more similar to typical farming practice than SER. The high genetic correlations of growth related traits between the third (one year old, mature) and second (seven months old) measurements could allow selection to be based on the earlier assessment, reducing handling stress close to spawning.

► We estimated genetic parameters for weight from two generations of common carp.
► We compared separate early rearing (SER) and communal early rearing (CER) of families.
► Higher heritability estimates were obtained from SER.
► Maternal and common environmental effects were close to zero in CER.
► CER conditions were closer to farming practice and allowed a shorter generation time.