Abstract
A total of 234 strains of tartary buckwheat (Fagopyrum tataricumGaertn.) cultivars from the world were examined to analyse the geographical differences in nine agroecological traits related to flowering and plant type. As for the relationships between the latitude, altitude of the collecting sites and each trait, a significant correlation was found in Chinese, Western Nepal and Eastern Himalayan strains, but not in strains for other areas.
To analyse the relationships among the strains, cluster analysis (Ward's method) and principal component analysis (PCA) using nine characters were carried out, and six agroecological groups were classified as follows; G-I: “compact slender type”with early flowering and short plant height; G-II: “bush type”with early flowering, short plant height and very large number of clusters; G-III: “slender type”with medium flowering, tall plant height and long main stem length; G-IV: “vigourous type”with late flowering, tall plant height and many branches. G-III and G-IV were subdivided into G-III-a and G-III-b, and G-IV-a and G-IV-b, respectively. The lack of significant relation between the agroecological traits and geographical factors was caused by the presence of several the landraces with different traits in the same area. On the other hand, when geographical differences were represented by the proportion (%) of six agroecological groups in each region, three characteristic areas were distinguished as follows; 1) G-I dominant area: at high latitude (>40°N) and altitude (>3000 m), 2) G-III dominant area: in central and southern China, and eastern part of Himalayas, 3) G-IV dominant area: western and midwestern Nepal.
Thus it was assumed that tartary buckwheat cultivars were affected not only by geographical conditions such as latitude and altitude, but also by human factors such as farming systems.
