Abstract
1. This experiment is one of the studies in which the authors intended to make clear the occurrence and mechanism of competition among genotypicaliy different plants. Five barley varieties (Table 1) were sown separately and mixed together in a randomized bfock design with three replications in the field experiment. Additionally, each variety was grown in pots to find. intervarietal difference of root development. The young plants of the varieties were measured in respect to their assimilative activity by the weighing method or the electroconductivity method (Fig.3), The intervarietal difference of top weight and number of tillers or heads was significant in the mixed 'plot, though not in the separate plot, while in other characters the difference was little in degree between the two sowing methods (Table 2 and 3). Such warp of normal pheno types of the variable characters, which seemed to be caused by the comp.etition among the varietie, s, occurred in the early growth stage and the variation became enlarged as the plants gew (Table 4). At the young stage the varieties were clearly different in their physiological and morphological characteristics such as assimilative activity, plant height, root growth and recumbence-habit. These genotypical differences seemed to act as an ihternal factor upon the occilrrence of competition (Table 6-11).
