Genotype by environment interaction in Nellore cattle from Amazon Legal region

Abstract

Genotype-environment interaction was studied by two different procedures in productive and reproductive traits of Nellore cattle. Data from adjusted weights at 120 (P120), 210 (P210), 450 (P450) days of age, scrotal circumference at 450 days of age (PE450) and age at first calving (IPP) for 211,744 records from Nellore herds located in the Legal Amazon region were used in the analysis. The effect of genotype-environment interaction was studied through heritability estimates and rank correlation, comparing the Legal Amazon animals with the general basis of animals – PMGRN Nellore Brazil. Bi-trait analyses considered P120 as anchor-trait with P210, P450 and PE450 as another one. IPP has been analyzed separately in single-trait analysis and considering GCIPP as fixed and additive and residual effects as random. Estimates of heritability for P120, P210, P450, PE450 and IPP on the data of the Legal Amazon were: 0.20 to 0.49; 0.21; 0.48; 0.45; and 0.21, respectively, and in general data of PMGRN – Nellore Brazil were: 0.23; 0.25; 0.34; 0.43 and 0.11, respectively. Correlations between rank for P120, P210, P450, PE450 and IPP were equal to 0.77; 0.79; 0.82; 0.78 and 0.38, respectively. The analysis of the genotype-environment interaction, through the heritability estimates, showed larger effects on maternal, weight at 450 days of age and age at first calving, whereas the rank correlations showed strong evidence in almost all traits studied.