Heterosis was calculated as the difference between
the mean performance of the hybrids and the mean
performance of their parent lines.Mid-parent heterosis
was expressed as a percentage of the mean performance
of the parent lines. Mid-parent heterosis was
estimated using the formula MPH (%)5100
(F1 MP)/MP where F1 is the mean performance of
the hybrid and MP is mean value of both parents.
MPH was calculated for weight, speci¢c growth rate
and CF.