Abstract
In order to analyze the mode of inheritance of the resistance to the infection with the virus (Yamanashi isolate), some experiments were carried out by using N124 as a resistant race and C124 as a susceptible race.
F1 and F2 hybrids were slightly more susceptible than C124. The backcrossed progeny of C124 to F1 hybrids showed a susceptibility similar to that of C124.
On the other hand, the backcrossed progeny of N124 to the F1 was highly resistant. In the relationship between log dosage-probit infectivity, the curve drawn on the basis of the experimental data coincided with the theoretical curve, on the assumption that one major gene controls the resistance.
As mentioned above, it is suggested that the resistance to the Yamanashi isolate is controlled by one recessive major gene.
