A complete diallele crossing experiment involving the Bohai, Denmark, Donaldson, Norway, and Californiastrains as well as self-breeding within each strain was carried out to evaluate general combining ability,specific combining ability, and reciprocal, maternal, and line-bred effects for body length and body weight inrainbow trout at four time points. The comparative analysis showed that the 20 corresponding cross combinationsand five strains from self-breeding were significantly different (P<0.05). Only a few genetic effects were significant,but the genetic effect was not the same among the different traits and time points. The Bohai and Donaldsonstrain cross combination had the fastest increases in body weight and body length, and length was significantlydifferent when compared with the self-breeding results. Combining the Donaldson strain with other strains lead tosignificantly higher body weights at 249 and 397 days of age. A significant maternal effect of the Denmark strainoccurred at 249 days of age. The maternal effect of the Donaldson strain on the length trait was significantly thelargest at 249 and 397 days of age. The cross combination of the Bohai and Donaldson strains was the most efficientamong all cross combinations, particularly for the weight trait. The effects of cross combination of the Bohaiand Donaldson strains on the length trait were positive (0.30, 0.03, 0.17, and 0.30) with a maximum at 771 days ofage. In conclusion, the Donaldson strain showed the highest growth performance of the rainbow trout offspring.The combination of the Bohai and Donaldson strains was the best and should be used as the basis for a breedinggroup.