A Preliminary Study oF Ancient Excavated Rice from

Yuchanyan SITE, Dao COUNTY, Hunan Province, PR CHINA

Zhang Wenxu l & Yuan Jiarong 2

(1China Agricultural University, Beijing 100094; 2Archaeology Institute of Hunan, Changsha, Hunan 410008)

 

(Acta Agronomica Sinica, 1998(24-4):416-420. July report. Formatted/scanned by G. W. Leir, ed. by B. Gordon & Weier Zhou)

 

 

Abstract. Four 12,000-14,000 year-old rice grains were found in 1993 and 1995 in Yuchanyan site, Dao County, Hunan Province. Their length resembles O. rufipogon, width is between japonica and indica, while L/W ratio, glume hair length and glume shoulder angle are between O. rufipogon and indica. The bi-peaked-tubercle is like japonica but the rice is awnless. As this original cultivated rice has O. rufipogon, indica and japonica traits, its name "Yuchanyan ancient cultivated rice" is proposed.

Key words Ancient cultivated rice; Yuchanyan; Dao County, Hunan

1 Discovery of ancient cultivated rice at Yuchanyan

 

        Yuchanyan is in Shouyan Town, Dao County, Hunan Province, China. 2530'N. Lat. & 11130'E. Long. It is in a karst limestone crag surrounded by planted pine forest and rice paddy. This crag site dates to the Palaeolithic (Fig. 1).

        Team vice-leader Yuan Jiarong of the Hunan Culture and Archaeology Institute excavated in 1993 and 1995, finding 10,000 year-old (C14) rice grain with potsherds, animal bone, spiral & freshwater mussel shells and plant seed. Two grains found Nov. 17, 1993, in washed T1-3H soil supplement two found Nov. 18, 1995, in a thick calcareous layer in T9-2b6-3b1. This layer also had a bone hairpin (Fig. 2), while T9-3E layer had ancient potsherds (Fig. 3).

2 Yuchanyan excavated rough rice grain length, width and L/W ratio

        For reference, length of 8 local indica grains range 7.22-8.74 mm (mean 8.30), 10 japonica range 6.81-8.18 mm (mean 7.46) and 9 common wild rice from Dongxiang, Jiangyong, Chaling, Guangdong and Guangxi range 7.94-9.39 mm (mean 8.74). The trend is from common wild rice to indica to japonica. As Yuchanyan grain length ranges 8.67-9.33 mm (mean 9.0 mm), it surpasses japonica to between common wild rice and indica, but on average, it resembles common wild rice.

        Width of 8 indica grains range 2.70-3.20 mm (mean 2.92), 10 japonica range 2.94-3.62 mm (mean 3.40) and 9 common wild grains range 2.04-2.96 mm (mean 2.58). The trend is from japonica to indica to common wild rice. As Yuchanyan grain width ranges 3.10-3.25 mm (mean 3.18), it is wider than common wild rice, reaching the upper limit of indica but within japonica. On average, it is wider than common wild rice and indica, but its narrowness resembles japonica.

        L/W ratio of 8 indica range 2.58-3.18 (mean 2.76), 10 japonica ranges 2.02-2.38 (mean 2.19) and 9 common wild rice range 3.03-3.89 (mean 3.39). The trend is from common wild rice to indica to japonica. As Yuchanyan L/W ratio ranges 2.80-2.87 (mean 2.84), it surpasses japonica, follows common wild rice and slightly higher than the indica mean.

        The above suggests Yuchanyan grain is larger, slowly evolving from common wild rice in width, a variation possibly altered via human choice (Fig. 4).

Figures 1 - 4

 

 

3 Yuchanyan rice glume hair length and shoulder angle

        Glume hair length of 7 indica samples range 262.0-453.3m m (mean 348.2), 8 japonica range 510.4-810.0m m (mean 605.4) and 7 common wild rice range 396.7-617.4 m m (mean 507.9). The trend is japonica to common wild rice to indica. Existing glume hairs in the broken 1993 sample are unmeasurable, but mean 1995 hair length is 452.0 m m; i.e., between japonica lower limit and indica upper limit, and midway in the common wild rice range. Mean is between common wild rice and indica, but nearer common wild rice. As glume hair range size was not chosen by farmers but natural, its shows Yuchanyan glume hair evolved from common wild rice to indica.

        Glume shoulder angle of 7 indica range 61-102 (mean 84.3), 8 japonica range 80-111 (mean 102) and 7 common wild rice range 59-81 (mean 73. 4). The trend is japonica to indica to common wild rice. Yuchanyan 80 angle is near common wild rice upper limit, japonica lower limit and midway for indica. Its mean between common wild rice and indica shows an evolution from wild rice to indica.

 

4 Yuchanyan rice bipeaked tubercle on lemma

        It was difficult recognizing 1993 Yuchanyan rice bipeaked tubercle due to its poor grain surface, but those of 1995 were clear and complete. Fig. 5 compares bipeaked tubercles, with Yuchanyan's bipeak straighter, like Jiangyong common wild rice and white shell rice, a local japonica variety. But it differed from Xiangzhongxian No.2 whose bipeak was V-shaped.

Figure 5

 

Table 1. Yuchanyan rice bipeaked tubercle on lemma traits

Material

Bipeak distance m m

Col depth m m

b. d/c. d

Peak angle

Col angle

Yuchanyan rice

32.0

2.4

13.3

80.5

163.0

Jiangyong (wild rice O. rufipogon)

32.5

3.5

9.3

70.8

155.7

White shell rice (japonica)

32.4

1.8

18.0

88.0

167.0

Xiangzhongxian No.2 (indica)

23.3

5.1

4.6

62.5

132.8

        Table 1 compares bipeaked tubercles, with shallow Yuchanyan col depth (2.4 m m) and high distance/depth ratio (13.3) and peak (80.5) and col angles (163). The "obtuse" bipeaked tubercle traits resemble Jiangyong wild rice and japonica white shell rice. But Xiangzhongxian No.2 (indica) col depth is deeper (5.1 m m), with smaller distance/depth ratio (4.6) and peak (62.5) and col angles (132.8). Its "sharp" bipeaked tubercle is very different from Yuchanyan rice.

        The distinguishing function of bipeaked tubercles are: Yuchanyan (-2.62), Jiangyong (-2.50) and white shell rice (-3.56); all "obtuse". But Xiangzhongxian No.2 is 9.06 or "sharp". Yuchanyan and japonica bipeaked tubercle are similar, but this may be an inherited form of wild rice, like Jiangyong county wild rice.

 

5 Yuchanyan 1993 initial distinction of "spore group" on the surface of lemma

 

        1993 Yuchanyan rice lemma surface has a "spore group", its size even, identical, round or elliptical, with surface pits and mean diameter 2.850.3m m (Fig. 6).

        Compared to paddy rice pollen, mean diameter of indica pollen is 33.142.47 m m, japonica is 32.781.4 m m, or 10x larger than the spore. As it is also round with one germinating hole, we may affirm this "spore group" is not paddy rice pollen. Its size and shape differs from lotus, Bluka and aquatic plant pollen [4, 5] .

        As spore diameters of 12 moss varieties range 15-20 to 100-200 m m and bryophytes are l0-20 m m, samples could not possibly be moss spores.

        Comparison was also made with fungus spores and paddy rice bacterium[6,7]. In diseases like rice blast, dry grain, flax spot, etc., common fungus spore shape differs, while diameter is much bigger. In dry white leaf and strip & brown spot bacterium, mycelia differ and diameter is much smaller. Paddy rice dry grain disease conidia are oval or elliptical and smaller and can squeeze out. Their ties are belt-shaped and survive the winter on diseased seed, invading grain the following year to infect flower and glume. "Spore group" shape, ecology and traits resemble 1993 Yuchanyan rice lemma surface, possibly belonging to one kind of dry grain mycelium, but thorough research is needed.

Figure 6

     

     

6 Opinions of Yuchanyan ancient rice traits

        Yuchanyan rice shape and trait analysis show length resembles common wild rice, width between japonica and indica (trend to japonica) and L/W at indica upper limit. Yuchanyan glume hair length is within range of common wild rice and indica, but nearer common wild rice. As glume shoulder angle is between common wild rice and indica, there was an evolutionary reduction.

        Yuchanyan bipeaked tubercle shape and other traits resemble japonica, while Jiangyong common wild rice initial state is maintained.

        As Yuchanyan top surface of lemma is awnless, completely unlike common wild rice, cultivation had begun.

        The above suggests Yuchanyan rice has concurring wild, indica and japonica traits of very primitive cultivated rice, which evolved from common wild rice, its most remarkable trait being "large grain". As a food source, ancient gatherers planted paddy rice to increase grain size, a variation worth attention. They did not care about adult plant shape and yield per unit area, only grain size. Wild rice grain length and width inevitably received attention, with intentional or unintentional choice an evolutionary factor in changing primitive cultivated rice to longer wider rough grain. As Yuchanyan rice expresses this evolutionary stage, it has important status and function in research on the origin and evolution of cultivated rice, a reference coordinate in its different periods. Thus, we propose the name "Yuchanyan ancient cultivated rice" for academic discussion.

References

1 Ding Ying, 1957, Agriculture Journal, 8(3):243-257

2 Chief Editor: Ying Cun Shan, 1993, China Rice Seed Resources, China Agriculture Science and Technology Publishing House, Beijing

3 Zhang Wen Xu, 1995, Beijing Agricultural University Journal, 21(2):143-146

4 Chief Editor: Ni Xue Ming, 1987, China Lotus, Scientific Publishing House, Beijing

5 Zhao Zuo Cheng, 1988, China Sieves (Bluka) Plant System Classification, Wuhan University Publishing House, Wuhan

6 China Crops Plant Disease Editorial Board, 1979, China Crops Plant Disease, Agriculture Publishing House, Beijing

7 Wei Jing Chao, 1982, Fungus Appraisal Handbook, Shanghai Science and Technology Publishing House, Beijing

8 Ten New Important Archaeological Finds in 1995: (2) Yuchanyan Site, Dao County, Guangming Daily. 5th ed., Mar. 26th, 1996

9 Zhang Wenxu, Tang Shengxiang, 1995, Chinese Research Newsletter, 3(3), 2-3