Abstract:
Crossbreeding is one of the tools for exploiting genetic variation. The main purpose of crossing chickens is to produce superior crosses (i.e. make use of hybrid vigor),
improve fitness and fertility traits.This study was carried out at the University of Limpopo
Experimental Farm located in Limpopo, South Africa. The objective of the study was to
evaluate the growth performance of differentpurebred and crossbred chicken
genotypes. A 3 x 3 complete diallel mating system involving two indigenous breeds
namely Venda (V) and Naked Neck (N) and one commercial broiler breed, Ross 308
(R), were used to produce three purebred (V x V, N x N, R x R), three crossbreds (R x
V, R x N, V x N) and three reciprocals (V x R, N x R, N x V).The nine genetic groups
were rearedfrom hatch to 13 weeks of age in a deep litter open house. Body weights of
180 chicks (20 chicks per genetic group), recorded at 0, 3, 5, 7, 9, 11, and 13 weeks of
age, were used to estimate heterosis, general (GCA) and specific (SCA) combining
abilities, maternal ability and reciprocal or sex-linked effects on body weights. Results
showed that the Ross 308 had the heaviest body weight at all weeks of measurement
except for hatch. With respect to crosses, the reciprocal V x R and the cross R x V had
the heaviest body weights at 13 weeks (2448.40 and 2131.50 grams, respectively),
although N x R had heavier body weight than R x V at all weeks of measurement except
for hatch and 13th week. Results of heterosis estimates indicated that crossing between
Venda male and Ross 308 female as well as between the Venda male and Naked Neck
femalegave the highest heterotic effects for body weight(11.01% and 10.33%,
respectively).General Combining Ability was significant (P≤0.01) for body weight from
hatch to 13 weeks of age while SCA and Reciprocal effects (RE) were both significant
(P≤0.05) for body weight at all ages of measurement except for hatch weight. The Ross
308 chicken gave the highest positive effect of GCA for body weight except for hatch
weight. Venda sire crossed with Naked Neck dams gave the highest and positive effects
of SCA for body weight. Naked Neck sire crossed with Venda dams had the highest
positive estimate of RE for body weight except for the 13th week. Results show that
using Venda chickens as a paternal breed in crossing with Naked Neck and Ross 308
females may improve growth performance of indigenous chickens.
