Genetic analysis of progeny performance through diallel crosses in common carp Cyprinus carpio cultured in varying inland saline water

A founder stock for creating synthetic population of common carp ( Cyprinus carpio ) was generated using a 3 × 3 diallel cross (Central India-CI, South and North East India-SI, and North India-NI) in a selective breeding program of common carp for inland saline aquaculture in India. Geographical stocks belonging to various locations were assembled at the CIFE Rohtak Centre. About 328 families (9 cross-types) were produced from 315 sires and 328 dams, with an average of 36 families per cross-type. A total of 4085 progeny (150 days old) were PIT tagged and further reared for seven months (210 days) communally in ponds at two salinity levels (S1:2–4 ppt and S2:6–8 ppt). Growth-related traits, viz., body weight (BW), standard length (SL), and body height (BH), were measured at tagging and at harvest age (seven months of pond rearing). The mean BW, SL, and BH at stocking and at harvest were 11.95 g, 6.97 cm, 2.56 cm, and 484.77 g, 23.40 cm, 9.28 cm, respectively. There was no significant difference for BW 210 across salinities (S1: 487.00 ± 4.22 g and S2: 427.71 ± 4.46 g), however, sex-wise, females (529.63 ± 3.66 g) outperformed males (384.36 ± 3.77 g). Among nine F1 cross-types, the CI×CI demonstrated the highest performance (496.53 ± 6.38 g) compared to the CIxSI (409.06 ± 11.97 g). The heterosis was non-significant indicating limited scope for cross breeding. Heritability estimates for BW, SL, and BH at stocking were not significantly different from zero viz., 0.08 ± 0.15, 0.12 ± 0.17, and 0.15 ± 0.14, and at harvest, the traits exhibited moderate heritability viz., 0.30 ± 0.05, 0.24 ± 0.06, and 0.26 ± 0.05 respectively, indicating scope for selective breeding. Strong and positive genetic correlations were observed across growth traits (r g = 0.73–0.98). The G × E interaction for body weight at two salinity levels was moderate (r g = 0.79). The growth performance of sibs evaluated under high salinity may serve as a useful indicator trait for indirect selection for salinity tolerance. • A founder stock of common carp comprising 328 families was established and evaluated. • Common carp exhibited body weight (range: 427–487 g) across two salinity levels. The female fish (529.63 ± 3.66 g) outperformed male (384.36 ± 3.77 g). • Marginal differences for growth traits were observed among 9 cross-types; however, the heterosis was not significant. • The growth traits exhibited moderate heritability (h²: 0.24–0.30) and strong genetic correlations (r g : 0.73–0.98). • The G × E interaction for body weight at two salinity levels was moderate (rg=0.79), indicating limited reranking of genotypes across environments.