Abstract
Genetic resistance to MD was examined by using two lines, H and L, selected for high and low competences in GVHR, and two B genotypes, B9B9 and B11B11. MD virus was inoculated at one day (Experiment I) or at 2 weeks (Experiment II) of age of chicks.
Although the L line seemed to be more resistant than the H line, the differences were generally small. The differences between the B genotypes were signiflcant statistically and the B11B11 chicks were resistant ones. Among the four groups of the GVHR-line and B genotype combination, L-B11B11 was extremely resistant to MD compared to the other three groups. The interaction of the GVHR-line and the B genotype was highly signiflcant statistically.
The correlation coefflcients of the GVHR competence with the post-inoculation days at MD incidence or MD death were all negative but not significant except one case.
