DIVERGENT SELECTION FOR DELAYED-TYPE WATTLE REACTION OF DOMESTIC-FOWLS TO BCG ANTIGEN

1. Two-way selection for delayed-type hypersensitivity wattle reaction (DWR) competence to BCG antigen was carried out over 4 generations, u sing a flock of White Leghorn chickens. DWR was measured by intraderma l injection of BCG into the wattle of chickens. 2. Selection for DWR w as effective. The generation means of average selection differential, selection response and realized heritability were 1.15 mm, 0.77 mm and 0.70 respectively. Correlated responses were found in body weight, eg g weight and hatchability. In all of these traits, the L line (selecte d for low wattle reaction) showed higher values than the H line (high reaction). 3. Specific trends in gene frequencies were observed at the major histocompatibility B and alkaline phosphatase Akp loci. 4. Sign ificant line differences were found in graft-versus-host reaction comp etence and Marek's disease resistance. In both characters, the L line was higher than the H line. No line differences were found in phytohae magglutinin reponse, phagocytic activity or immune responses.