Parâmetros e tendências genéticas para características de interesse econômico em linhas puras de frangos de corte

Abstract

In breeding programs, the continuous estimation of genetic parameters, as well as the identification of genetic changes during the selection process, are essential for the validation and adjustment of the selection indices used. Thus, the present study was developed with the objective of obtaining estimates of heritability and genetic correlations, as well as genetic gains over the years, for the traits Breast Measurement Index (IMP), body weight at 35 days of age (P35), and total number of eggs produced until 64 weeks of age (NO) in purebred broiler lines (KK, TT, and PP) of Embrapa Swine and Poultry breeding program belonging to the genetic improvement program. The estimated heritability for the growth traits (IMP and P35) showed moderate magnitudes, ranging from 0.41 to 0.50, while for the reproductive trait (NO), the values were low, between 0.29 and 0.31. Genetic and phenotypic correlations between IMP and P35 were positive in the KK and PP lines and negative in the TT line. For the relationship between IMP and NO, the KK and PP lines showed negative correlations, whereas the TT line showed a positive correlation. Between P35 and NO, a possible genetic antagonism was observed in all three lines, with negative genetic correlations. Analyses of additive genetic trends indicated positive and significant increases over the years for all evaluated traits in the three lines. The findings reinforce the effectiveness of the selection process adopted and provide relevant support for future research, especially in the development of more comprehensive selection indexes that integrate multiple traits, aiming to maximize genetic gains in a sustainable manner.