Genotype x ecological region interaction in the Nguni cattle breed

Author: M. van Niekerk, F.W.C. Neser and J.B. van Wyk
Year: 2004
Issue: 6
Volume: 34
Page: 116 - 118

Weaning weight (WW) records were used to investigate the presence of a genotype x ecological region interaction as well as the magnitude and significance of such an interaction. Records from herds were allocated to one of three veld types that described the specific region in which each herd was situated, i.e. sweetveld (Region 1), sourveld (Region 2) and mixed veld (Region 3). The data set consisted of 2136 records for Region 1, 3984 for Region 2 and 11432 for Region 3. Weaning weight data from each region was considered as separate traits and two trait analyses of the three different regions were carried out to determine (co)variance components. Weighted direct heritability estimates for WW ranged from 0.23 to 0.45. Direct genetic correlations of Regions 2 and 3 with Region 1 were significant and were 1.00 and 0.71 respectively. This indicates that no G x E occurred between Regions 1 and 2, but indeed between Regions 1 and 3. The genetic correlation between Regions 2 and 3 (0.60) were not significantly different from 0.

Keywords: beef cattle, genotype x environment interaction, growth traits
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