Variation in phenological and morphological traits of cultivated and wild populations of Arthraxon hispidus collected from Hachijo Island and Kinki district [Japan]

Arthraxon hispidus (Thunb.) Makino (Poaceae) is an annual weed in arable and ruderal sites in Japan. It is used for dying silk fabric, and has been brought into cultivation in Hachijo Island for this purpose. Three accessions from farmers' seed-stocks, 11 wild accessions collected in Hachijo Island and 5 wild accessions collected in the Kinki district (Table 1) were grown under uniform conditions, and 26 traits were compared. A retmarkahlv high variahility was observed in the phenological and morphological traits among wild and cultivated accessions. The cultivated accessions showed a typical domestication characteristics such as synchronous branching and heading, larger leaves, enlarged spikes and spikelets and longer internodes, and uniform maturation compared with the wild accessions. Two wild accessions from Hachijo Island showed the same characteristics as those of the cultivated accessions (Fig. 1 and Table 2). The first and second principal components, which were derived from 16 quantitative traits, illustrated the morphological and phenological differences among the cultivated accessions from Hachijo Island, wild accesions from Hachijo Island and wild accessions from the Kinki district (Fig. 2). It is likely that the presence of the adaptive characteristics in the cultivated accessions was due to unconscious selection under cultivation and partly to conscious selection for higher yield or better quality of the dye.