Interação genótipos-ambientes e parâmetros de adaptabilidade e estabilidade para características de crescimento em bovinos de corte compostos no Brasil

Abstract

CINTRA, D. C. Genotype-environmental interactions and adaptability and stability parameters for growth traits in composite beef cattle in Brazil. Data from 111,101 weaning weight adjusted to 205 days (WW), 50,860 yearling weight adjusted to 390 days (YW) and 47,462 weight gain from weaning to yearling (WG) were analyzed to evaluated the genotype-environmental interactions and estimates adaptability parameters for seven genotype combinations of crossbreed beef cattle, raised in three environment of the Brazil.. The genotypeenvironmental interation effect was significative (P<0.01) for all de traits analyzed. The sum squares decompositions of genotype-environmental interations, were accomplishment by regression method for each trait analyzed. Were verified, through the slopes of the regression lines that, for WW, the animals considered as wide adaptability were genotype composition 7. The genotype compositions 2, 3 and 6 were considered of specific adaptability for favorable environments, and genotype compositions 1, 4 and 5 were classified as combinations with specific adaptability for unfavorable environments. For YW, the animals considered as wide adaptability were genotypes compositions 1 and 3. The genotype compositions 2, 6 and 7 were considered of specific adaptability for favorable environments and genotype compositions 4 and 5 were classified as combinations with specific adaptability for unfavorable environments. For WG, the animals with genotype composition 4 and 5 were considered as wide adaptability, while the genotype compositions 1, 2 and 3 were considered of specific adaptability for favorable environments and genotype compositions 6 and 7 were classified as combinations with specific adaptability for unfavorable environments.

Comparação de estimativas de diferenças esperadas de progênie por três metodologias em touros da raça Nelore

“…Segundo Lee e Bertrand (2002), em estudos envolvendo populações da raça Hereford, o ganho de peso pós-desmama mostra-se afetado pelo efeito da interação genótipo x ambiente. Cintra (2007) e Ribeiro (2005) também relatam o efeito da interação em estudos envolvendo bovinos compostos e Nelore, respectivamente. Além disso, a alta correlação genética encontrada entre peso a desmama e tamanho corporal, da ordem de 0,97, indica que a seleção para peso à desmama estará promovendo um aumento no tamanho por resposta correlacionada (CARDOSO et al, 1998).…”