Studies on the geographical variatiou of some characters of Renge, Astragalus sileicus L.,

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The place of origin of Renge, Astragalus sinicus L., was probably in China. It is believed that Renge was introduced into Japan from China as early as the 5 th century A. D., though it is uncertain. This exotic plant spread throughout Japan, because the natural environmental conditions were suitable for its growing. Nowadays, Renge grows all over Japan except Hokkaido-area as valuable manure and forage crops or wild plants. The authors collected numerous strains of Renge growing under various environments and studied the geographical differentiation among them. The results obtained are summarized as follows : ( 1 ) In both cultivated and wild strains, strains collected from cooler climates tended to flower somewhat earlier, to be shorter in plant height, smaller in leaf size and more prostrate in plant type than those from warmer climates. The degree of these variations with latitude is greater in wild strains tban in cultivated ones. For example, in regard to the flowering date, an increase of 1° in latitude resulted in a promotion of 1.5-1.9 days in wild strains as compared with 0.2∼0.8 days in cultivated strains. ( 2 ) Not only in the mean value mentioned above, but also in the within-plot-standard deviation, an apparent geographical trend was found in some characters, that is, a continuous gradual decrease in standard deviation was recognized according as the latitude increases. It was fcund in wild strains that correlation coefficients between the latitude and the within-plot-standard deviation were -O. 508** in plant type index, -0.373** in plant height, -O.358** in leaf length and -0.403** in leaflet area index (*'* indicating the significance at the 1% level. ). Contrary to these results, in flowering date and number of stems a positive correlation was calculated, but the values themselves were small and not significant. These results rhay be useful in considering how Ito introduce Renge plants into our country. ( 3 ) Cultivated strains have generally more valuable characteristics as fcrage crops than wild strains as expected. Namely those of more erect plant type, taller plant height, Iarger leaf size, and so on are recommended.