The study was conducted to evaluate the combining abilities of the growth traits resulting from a complete diallel crosses of the three strains of Oreochromis macrochir from Chambeshi, Kafue and Luapula rivers conducted at Misamfu Aquaculture Research Station in Zambia.
A complete diallel cross was used to evaluate combining abilities, reciprocal effects and maternal effects in a randomized complete block design. The fry from the diallel cross were held in 1m x 1m x 1.3 m hapas installed in 600m2 earthen pond, stocking density of 250 fry/hapa. Fry were stocked at mean weight of 0.04g (± 0.001) across all treatments, and the study lasted for 70 days.
Note: FBW – Final body weight; SL – Standard length ; SGR – Specific growth rate; CH – Chambeshi; KA – Kafue; LU - Luapula
The results showed significant differences (P <0.05) in FBW , SGR% and SL . Best general combining ability (GCA) of strains on final weight was Luapula (0.180±0.022) followed by Chambeshi (-0.009±0.009 ) lastly Kafue with a highest negative value (-0.172±0.018 ).
The best specific combining ability (SCA) for final body weight was Chambeshi x Kafue or Kafue x Chambeshi (-0.350±0.028 ) followed by Chambeshi x Luapula or Luapula x Chambeshi (-0.379±0.013). The reciprocal effects and maternal effects were not significantly different (P >0.05) for the three strains. The Luapula strain is recommended for genetic improvement program for it showed better growth and general combining ability.
Key words: Oreochromis macrochir, diallel, general combining ability, specific combining ability, reciprocal effects, maternal effect.