Genetic and phenotypic response in Vanaraja male line chicken under short term selection experiment

Abstract

The genetic and phenotypic response for 6 weeks shank length (SL6) and correlated response for body weights at 2, 4 and 6 weeks of age were evaluated in short term selection experiment in Vanaraja male line (PD-1) utilizing the data collected for the last 6 generations in a pedigreed mating. The direct response in SL, the primary trait was 2.01±0.85 mm on genetic scale and 2.35±0.36 mm on phenotypic scale. The SL was 68.07±0.004 mm in first generation of study (S4) which gradually improved to 81.01±0.002 mm over the last 6 generations. The correlated genetic response in body weight at 2, 4 and 6 weeks of age was in positive direction though not significant. The body weights improved as correlated response to the primary trait. The phenotypic response in body weights was in positive direction and significant at 6 weeks of age; however at 2 and 4 weeks, it was not significant. The effective population size (Ne) ranged from 150 to 167, the selection intensity (i) between 0.24 to 1.09 and rate of inbreeding from 0.0029 to 0.0033 in the last 6 generations. The realized and estimated heritability estimates were 0.17 and 0.12 for 6 week shank length, respectively. The study concluded that, the genetic and phenotypic responses were positive over the generation with a gradual improvement in the primary trait as well as the juvenile body weights in PD-1 line. The improvement trend was also reflected in Vanaraja, a terminal cross produced for rural/backyard poultry using PD-1 as male line.