The inclusion of genetic groups in the pedigree has
decreased the heritability estimate for harvest body weight, implying that there are strain additive genetic effect and heterosis in the base generation.
Heritability estimate for the harvest body weight
in the present study was in general lower than
those reported in other selection breeding programmes
for shrimp growth. The lower heritability
estimate was most likely caused by low genetic
variation in the population, as the strains have
been domesticated and selected for multiple generations
before they were introduced. Even so,
higher genetic gain for growth could be obtained
in future by cross-breeding and selective breeding
by increasing the selection intensity.