4

We found that: 1) The carbonized grain differed in size according to layers, as shown in Table 1.
The grain from the 4th layer were significantly longer than those from other layers. They also had
larger mean values of width and thickness. This was due to an addition of large grains to the
population increasing interplant variations.

The 8th to 4th layers showed at increasing trend of coefficient of variation for grain thickness.
In grain length and width, grains from the 4th layer showed larger variability than those from the
8th layer, although the 6th and 7th layers in the middle had almost the same variability (Table 1).
This suggests that the rice grains in the oldest age were relatively uniform, and variability increased
later, particularly in the latest neolithic age.

2) The dimensions of carbonized grain were compared with those of present local varieties grown
in Nanjing area. In length/width ratio, the ancient rice generally had greater values than the present
varieties. The volume of grain as estimated by (length x width)^ 1/2 and (length X width X thickness)
1/3 was smaller than corresponding values for the present local varieties (Table 2). The grain from
the 4th layer showed comparable values with some of present varieties.

Table 2. Dimensions of carbonized grain as compared with present local varieties

The silica bodies or plant opals were examined in the soil samples. The beta type
representing the Japonica grains were found in all layers except for the 8th layer (cf. Sato
et al. 1990).

It may be inferred that with the initiation of rice cultivation, the variability within populations
increased. The development of rice culture was slow in the early stages, but was faster in the
later period, say. 6300 to 5500 years before present. Conscious artificial selection would have
been practiced in this period. According to the shape of plant opal in the ancient site, the earliest
cultivars seem to be of Japonica type.

Sato, Y. I., H. Fujiwara and T. Udatsu. 1990. Morphological differences in silica body derived
from motor cells of indica and japonica rice. Japan. J. Breed. 40: 495-504.

Table 1. Mean value, standard d deviation and coefficient of variation for dimensions of carbonized rice excavated at a vestige site of Gaoyou
Layer:		4	6	7	8
Number of grains sampled:		118	48	65	14
.Length Mean (mm)		5.8	4.6	4.7	4.8
S.d.		0.89	0.51	0.58	0.47
Coef. variation	(%)	11.9	11.1	11.9	9.7
Width Mean (mm)		2.6	2.3	2.3	2.2
S.d.		0.45	0.30	0.31	0.23
Coef. variation	(%)	17.9	13.1	13.6	10.2
Thickness Mean (mm)		1.78	1.65	1.69	1.65
S.d.		0.41	0.29	0.23	0.21
Coef. variation	(%)	23.0	17.6	13.7	12.7

		L-length	W-width	T-thickness
Material		L/W	(L-W)^½	(L-W-T) ^1/3
Carbonized grain	4th layer	2.31	3.85	2.97
	6th layer	2.03	3.22	2.57
	7th layer	2.07	3.29	2.64
	8th layer	2.19	3.28	2.61
Present Local variety	Ai Huang Zhong	1.94	3.96	3.00
	Chang Jing Uu Nuo	1.82	3.78	3.01
	Hei Zhong	1.78	3.91	3.06
	Huang Zhong	1.96	3.88	2.98
	Carbonized	2.07	3.91	2.88