Domestication of plants during the Jomon period

Abstract

This paper compiles archaeobotanical size data of soybean, azuki, and Echinochloa (barnyard grass) and discusses the process of morphological domestication (seed enlargement) of these three plants during the Jomon period. The archaeobotanical records of soybean and azuki increased from 6000 to 4000 years ago in the Chubu and western Kanto regions (Moroiso-Katsusaka Pottery grope), and the records include seeds larger than modern wild species. This trend was linked with the population growth in this region, and morphological domestication probably started from this period. However, small seeds have also been seen in this stage ; gathering of wild species by the people probably still continued, or large seed species were not fixed. Large seed species disappeared in the Chubu region 4000 years ago ; however, the large seeds can be seen in Kyushu and western Japan. Probably the large seed species were fixed from this stage, and cultivation of these large species at least had started in this period. In the case of Echinochloa (barnyard grass), the seed size temporally enlarged 6000 years ago in the northern Tohoku, and 4500 years ago in the southern Hokkaido region (Ento pottery group). This seed enlargement was also linked with population growth in each period and region. There are some possibilities that morphological domestication temporally occurred in these periods ; however, large seeds were not seen until the 10th century. Since the small seeds of Echinochloa were not seen after the 10 th century, it seems that the large seed species have been fixed since this period.