1) Institute of Food Crops, Jiangsu Academy of Agric. Science, Nanjing, 210014, China
2) Faculty of Agric., Miyazaki University, Miyazaki, 889-21 Japan
Research workers in Nanjing Museum excavated the vestige site of Caoxie Hill
in Wu county, Jiangsu province, in 1972 and 1973. A series of materials
including fossil rice were unearthened, which represented different periods
ranging from Ma iaban (4,000 BC) to Warring-States period (400 BC). These
fossile rices were authenticated as remains of Japonica cultivars. The types
of rice planted in those ancient periods would be significant in studying the
origin and evolution of cultivated rice.
The present study was conducted by excavation and survey at the vestige site of Caoxie Hill. Three survey pits each 5 x 5 m
2 were excavated. Examining the materials from different layers, the first layer was determined as the modern one, the second as the layer of Song Dynasty, the third as of Warring-States period, the fourth as of Songze, and the fifth as the late Majiaban period; the 6th and 7th layers are due to the middle and early periods of Majiaban, respectively. As an example, various cultural layers observed in a survey pit 92WCT0406 are shown in Fig. 1, in which the fourth layer is absent.A total of 15 soil samples were taken from this pit and 50 plant opals from each sample were examined. Lengths at the top (a) and bottom (b), width (c)
1. Layer of present time
2. Layer of Song Dynasty
3. Layer of warring-States period (40OBC)
5. Layer for Majiabin late period (3,70OBC)
6. Layer for Majiabin middle period
7. Layer for Majiabin early period
and thickness (d) were measured in each opal under microscope. For
distinguishing between Japonica and Indica types of an opal, a function was
constructed as follows: Z=0.049(a+b)-0.019c+0.197d-4.79(b/a)-2.614 (Sato et
al. 1989). The results showed that more than 90% of plant opals belonged to
the beta type and were of Japonica type. This suggests that Japonica types were
planted at the beginning of rice culture around the Caoxie Hill site.
References
Sato, Y. I., H. Fujiwara, T. Udatsu and H. Morishima, 1989. Plant opal
analysis as a method of distingsuihing between subspecies indica and japonica
of O. sativa. RGN 6: 67-69.