Effects of the individual rearing stage on the growth traits of candidate giant freshwater prawns (Macrobrachium rosenbergii)

In most breeding programs of Macrobrachium rosenbergii, the candidate parents will go through an overwintering period of individual rearing stage (IRS) after the communal rearing stage (CRS). To study whether environmental differences affect the growth traits of candidate parents, the heritability (h2) and genotype by environment (G × E) interaction were estimated for harvest body weight (HBW) and average daily weight gain (ADG) in CRS and IRS. The HBWs and ADGs of 3,242 candidate parents from 111 families were recorded at the two stages. The h2 estimated for the HBW and ADG in the CRS were medium to high (0.333 ± 0.205 and 0.284 ± 0.173) and decreased to a medium magnitude in the IRS (0.158 ± 0.032 and 0.171 ± 0.034). The heritabilities for HBW and ADG were higher in females than that of males in CRS, but the situation reversed in IRS. No significant differences were found in heritabilities of HBW and ADG between males and females in the two stages (P > 0.05). For HBW, the genetic correlations between the two stages were 0.32 ± 0.18 for all candidates, 0.98 ± 0.021 for females and 0.073 ± 0.24 for males. For ADG, the genetic correlations between the two stages were − 0.37 ± 0.16 for all candidates, − 0.079 ± 0.20 for females and − 0.51 ± 0.18 for males. The IRS had an obvious influence on the growth traits of candidates, especially for males. To select parents more accurately, growth in the IRS should also be taken into consideration in parent selection and mating schemes in breeding programs of M. rosenbergii.