Abstract
The interplant variation of plant height within plot was analyzed in relation to the variation of flowering time using a set of F1 diallel crosses between six inbred lines of rustica tobacco grown in two environments, the early and late transplantings. The interplant variation of plant height in a genotype was partitioned into two components ; the one dependent on flowering time and the residual one independent of flowering time. The former was mainly due to the additive effect of genes and the genetic effects on it were not consistent to the environmental changes. The latter was due to the additive and non-additive effects of genes which were relatively stable against the environmental changes. There was no genetic relationship between the two components in both environments. From these results, it was suggested that the two components of the interplant variation of plant height were controlled by different genetic factors. Neither the dependent nor the residual interplant variation was correlated with the phenotypic plasticity, which was estimated in terms of the ratio of phenotypic difference to the mean value between the environments.
