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TWO PROBLEMS ABOUT THE ORIGIN OF CHINESE RICE CULTIVATION
ZHANG, Kaisheng
Editorial Dept., Cultural Relics of Central China Journal, Henan Museum,No.8 Nongye Road,Zhengzhou,
Henan, PR CHINA (Agricultural Archaeology 1998(1):228-231,254. Translated by Yu Chen, edited by B. Gordon)
Not only is China a world origin of agriculture, it is also the central source of rice cultivation. As rice is its
crop used continuously for the longest time, its origin has been discussed for almost 50 years, and is important both
for research on social growth and agricultural progress. Ding Ying presented the theory of a south China origin in
the 1950's, while a Yunnan-Guizhou Plateau origin was popular in the 1970's. Post-1980 comments are always
evolving; e.g.s, origins on the lower or middle Yangtze, lower Yellow, Yangtze-Huai, etc. New archaeological finds
not only enrich study materials and add insight to research, but impact and test different theories at different levels,
so that research proceeds. There are ca.100 Neolithic rice sites, some in the Yellow and Huai Basins, but most on the
middle and lower Yangtze, the earliest being 10,000 year-old Yuchanyan Cave in Daoxian, Hunan Province[1].
8,000 year-old carbonized domestic rice in Peiligang culture Jiahu sites in the Huai Basin and south to the Yangtze
extend ancient and modern wild rice north, raising interest to discuss and understand problems on rice cultivation
origin. In this paper, we give some short comments on the second problem related to the origin of Chinese rice
cultivation.
1. Origin of Rice Cultivation and Origin of Rice Grain
Rice origin and its cultivation are different concepts, but co-relationships exist. Cultivation origin includes
rice biology and social sciences like history, anthropology, etc., while rice origin focuses on biology and genetics in
the natural sciences. As both mix imperceptibly in origin discussions, an understanding of rice cultivation origin
must not be hindered because it is an important problem which some scholars recognize. Liu Zhiyi mentioned this in
his paper on rice cultivation origin: "some scholars blend three different concepts, origins of rice, rice cultivation
and agriculture because they think solving rice origin solves cultivation origin and agriculture, but cultivation origin
is when and where rice was first planted, while origin means where rice came from and how it evolved from grass".
The so-called Assam-Yunnan, hillside zone and south China theories were all based on wild rice distribution[2].
As the main base for rice origin is a suitable ecotone, its ancestor is generally common wild rice, and we
may find the origin of cultivated rice once we know the origin of common wild rice. A central origin of cultivated
rice may exist where ancient conditions for common wild rice are good.
Besides a suitable ecotone, humans are the heaviest involved in cultivated rice origin because social
conditions in wild rice communities exist to satisfy food demands; i.e., cultivated rice origin is a cultural activity
only occurring when society grows to a certain level, while wild rice origin depends on nature and restricted only by
ecology. If only wild rice existed without cultivation, rice agriculture would be meaningless.
Common worldwide properties exist between cultivated rice and agricultural origins. Rice agriculture is a
passive activity acted upon by people under food stress. Doubtless those with extensive gathering experience had
advantages in rice cultivation, but if people lived comfortaby on hunting and gathering, complex cultivating activity
would be unnecessary.
We know people began cultivating rice after the Late Paleolithic because of its glaciations and widespread
low temperature. In particular, northern hunter-gatherers were threatened by greatly decreasing food, when
warmth-loving plants moved south and berries decreased, while grasses with their seed spread and became the main
object of southern gatherers. As the relationship between northern people and plants strained, southern people
familiarized themselves with plants, gradually cultivating them for food. But glacial climate restricted seed plant
cultivation, even more so with warm wet-loving rice. As rising Holocene temperatures met external conditions for
rice cultivation, more experienced southern gatherers gradually became agriculturists. South of the glaciers where
their effects were minor, tropical people retained conventional hunting-gathering and did not adopt planting for
many years. Even good wild rice conditions couldn't stimulate the origin of agriculture without pressure. On the
contrary, some harsh environments were centers for many agricultural inventions. As the English historian Arnold
Toynbee concluded in Study of History, the growth of civilization always resulted from challenge and resistance, the
earliest civilizations rising in poor areas; e.g., where equatorial and southern hemisphere people like aborigines in
Australia, Pacific Islands, south Africa, etc., were full-time hunter-gatherers. Compared to the central plain, a
comfortable lifestyle was delayed in several south China minority areas under warm climate. As we must consider
positive and negative effects of the natural environment when discussing rice origin, ecological and genetic
interpretations must be rethought. It is absurd that a crop mutation centre in a major environment be considered a
rice origin. Kent Flannery’s Fringe Zone Theory on agriculture origins, referred to Harland's wild wheat study that
"cultivation didn't occur with wild seed, but in its surroundings under worse conditions"[3]. Simultaneously,
"highland wild plants move to valleys with plentiful water, just like Chevalier? Valley and south Sahara broom and
pearl millet, being drought-resistant, moved from dry meadow far from its centre. As the dry highlands north and
west of the valley where millets were cultivated were only marginal to the center"[4], it is obvious these places were
not origins of cultivated crops.
Biologically, the tropics and subtropics are the most complicated ecotones with maximum plant mutation.
Early Holocene studies of the 7-10,000 year-old Early Neolithic reveals a tropical or subtropical climate in several
south China provinces. With their large tropical rainforests it was ideal for different crops among the many plant
species in Guangdong, Guangxi, Fujian, Yunnan, etc. In fact, the >15,000 species in Yunnan gave it the name
Kingdom of Plants. Almost 3,000 types of rice exist, distributed from 40 m to 2800 m ASL, yet its earliest rice sites
are only 4,000 years-old. That it also had several common wild rice, but no Early Neolithic cultivated rice, must
relate to the wet warm south China climate. As this good environment provided sufficient animal and plant
resources, hunting-gathering persisted without grass family grain cultivation. Later grass family cultivation began
when tropical and subtropical people were in the so-called horticultural period, growing only asexual root plants
like potato and taro. Hence, this area may be the origin of wild rice, but not the origin of rice agriculture.
1. Differentiation between japonica and indica
Rice experts recognize a close relationship between climate change and japonica-indica variation based on
japonica-indica distribution. When discussing this variation, Chinese agronomists say cultivated indica evolved
from common wild rice, while cultivated japonica is a variety of japonica which spread from south to north and
from lowland to highland, adapting to colder environment after entering the temperate or mountain zone[5]. In the
1950's, Ding Ying considered biology, geography, climate and japonica-indica environment, thinking indica was
the earliest domesticated rice because its traits and shape are closest to common wild rice. As japonica and wild rice
have very different traits and shape, japonica might have been chosen artificially from single indica plants or wild
rice in different conditions[6]. In sum, humans cultivated indica from common wild rice and cultivated japonica
from indica under low temperature.
But it seems that new finds don't support this view completely, as genes also caused variation of japonica and
indica, their evolution worth further discussion on single or separate origin theories. The latter says japonica began
in India, indica in China, followed by propagation. The former says common wild rice is the ancestor of japonica
and indica, despite their differences. Traditional comments say of japonica-indica differentiation happened in
different environments after wild rice was cultivated. Wild rice evolved into japonica and indica types naturally,
becoming japonica and indica after cultivation. Regarding different rice origin involving one or more centers, Zhou
Xiaolu illustrates differences on japonica-indica origin in models A,B and C below:
(A type) wild rice --(man's effect)-->indica------(man's effect)--->|indica
|japonica
(B type) wild rice ------(man's effect) ----->|japonica
|indica
(C type) early wild rice---(natural effect)---->|japonica wild rice(man's effect) ----->|japonica
|indica wild rice(man's effect) --------> |indica
In addition, a model shows the theory about separate japonica and indica origins:
Indian type (indica) wild rice---(man's effect)--->indica
japonica type wild rice------------------------------>japonica
We prefer model C which can be explained in 3 aspects.
1. Generally, there were different types of China wild rice.
Wild rice includes common, warty and medical types. The common type is usually recognized as ancestral
to cultivated rice. If it evolved naturally into different species of diverse ecotype, it might be possible for them to
evolve to japonica and indica. It is distributed from Yak Ian, Hanna Ado to Dongxiang, Jiangxi Province; and from
Yinjiang; Yunnan Province to Taoyuan; Taiwan[8]. Wang Xiangkun said it didn’t obviously evolve into japonica
and indica due to divergent climate, but a continuous distribution between them occurs, with most japonica-hybrid,
indica-hybrid or japonica-indica-mixed type. Most common wild rice is japonica-hybrid types in Dongxiang,
Jiangxi Province and Chaling Jiangyong, Hunan Province. Both japonica and indica are in Guangxi Province, with
mostly japonica and japonica-hybrid types. Indica-hybrid common wild rice is mainly in Guangxi, Guangdong and
Hainan in south China[9]. Many papers used to say Jiangsu Agriculture Academy found japonica type wild rice;
e.g., the Chinese Agriculture Genetics research group and Jiangsu Agriculture Academy signed a common
identification report in 1973 of ancient rice in Jiaozhuang, East China Sea, saying "the academy collected wild rice
in Yuntai Shan before the Cultural Revolution and identified as japonica"[10]. Careful fieldwork showed some
annual japonica type common wild rice in 29 places in Yuntai Shan, Lianyungang. Zhou Shilu also found japonica
type common wild rice in Chaohu, Anhui Province. These are enough to prove common wild rice evolved naturally
to indica-hybrid type or japonica-hybrid type. As there are japonica type and indica type common wild rice, some
common wild rice are so inclined. In sum, cultivated rice at first might include japonica type or indica type, with
japonica and indica later cultivated in different places.
2. Common wild rice evolution to japonica and indica is proven.
To assess original wild rice potential to evolve into two types, Hikoichi used a wild strain to hybridize with
typical japonica and indica strains. Results show an indica-like strain from the japonica-wild rice combination, with
a japonica-like strain from the other group[11]; i.e., wild rice has genes for japonica or indica. Yo-Ichiro Sato
used molecular genetics to show DNA genes in rice chlorophyll, finding strict differences between macromolecules
compiled by indica and japonica genes. They analyzed various systems like combined wild and cultivated rice, with
no trait distinguishing wild and cultivated rice groups. On the contrary, they easily divide into two groups
resembling japonica and indica, but these are not rigid cultivated rice types. The biological rice class includes wild
rice before cultivation[12]. Sato showed japonica- indica differentiation began long ago, before cultivation,
agreeing with Hikoichi's analysis. Results don't disprove cultivation accelerated evolution from wild rice to
japonica-indica.
3. Mixed growth of indica, japonica and wild rice in ancient rice sites.
Identification showing the distribution of most southern rice as indica and northern as japonica also applies
to Neolithic rice. Indica, japonica and wild rice co-exist in many early sites; e.g.s, >100 8,000 year-old carbonized
grains in Jiahu site, Henan, where phytolith, kernel and length: width ratios show mostly japonica, some indica and
little common wild rice[13], 70% of Luojiajiao site rice in Tongxiang town, Zhejiang Province, is indica, the rest
japonica[14]; and rice in Hemudu site identified and counted by Zhou Jiwei from Yunan Agriculture Academy, who
found 60.32-74.59% indica, 20.59-39.68% japonica and 3.6-4.4% intermediate[15]. The latter exists because
indica and japonica traits can be differentiated into a combined group of Asian cultivated rice. Later SEM
separation of these grains lead researchers to believe "common wild and original cultivated rice grew in
proximity...that Hemudu’s mixture was not artificial but represents early rice evolution where all co-existed...to
conserve species". Doubtless, different indica and japonica types, plus a few wild rice co-occur in 7,000 year-old
sites because rice cultivators still supplemented with wild rice, allowing cultivated rice to be sown with wild rice, as
both grew well in the same place. This agrees with the abovementioned results of Sato and Hikoichi, where it is
possible for wild rice evolution to japonica and indica. Such capacity perseveres even under artificial cultivation.
That indica and japonica exist together in Hemudu and Jiahu epitomizes wild rice diversification.
As common wild rice trends to japonica and indica, gene analysis of modern and ancient cultivated rice
show their differentiation occurred before wild rice was cultivated. It can be imagined that thousands of conditions
could cause many modern rice varieties, yet only one wild species existed in different ecotones. Although rice likes
warm wet environments, different wild rice ecotones changed with world climate change. As widespread Late
Paleolithic glacial climate greatly promoted species variation, including rice, indica-japonica differentiation
separated cold-resistant and warm-loving rice. Wild rice may have its own bi-directional japonica-indica gene, with
the capacity to differentiate cold-resistant species in cold or wet conditions. In contrast, it kept its warmth-loving
indica-type traits in the original ecotone under good temperature and humidity. The survival of the fittest suggests
rice multi-type traits appeared because of gene tendencies in warm and cold climates. As cold-susceptible common
wild rice is eliminated in cold conditions, the survivor gradually evolved into japonica or hybrid japonica. That
some perennial wild rice gradually became annuals under low temperature and seasonal change reflects the slow
unbalanced evolution of cultivated and wild rice in China from south to north, from lowland to mountain. Natural
variation is especially slow, even though cultivation accelerates it. We conclude that the capacity to vary in the
common wide rice gene is the base of indica-japonica differentiation, which climate is a necessary condition and
that cultivation accelerates differentiation.
References:
[1] New important evidence from Yuchanyan Cave. Chinese Journal of Material Culture (1), March 3, 1996
[2] Zhiyi Liu. Note on the origin of rice agriculture. Agricultural Archaeology 1994(3)
[3] Moriki: Theory of the origin of agriculture. Agricultural Archaeology 1989(2)
[4] Yaoli Wu. Opinion on the appearance of agriculture. Agricultural Archaeology 1997(1)
[5] Xiuling You. Several comments on rice found in layer 4 in Hemudu site. Material Culture 1976(8)
[6] Ying Ding. Origin of Chinese cultivated rice and its evolution. Agriculture Journal 1957(8)(3)
[7] Xiaolu Zhou. Archaeology notes on rice origin: Part I. Agricultural Archaeology 1994(3)
[8] Chinese rice agriculture. Chap. 1 (ed. by China Agricultural Academy. China Agriculture Publishing
[9] Xiangkun Wang. Preliminary questions on the study of Chinese common wild rice. Agricultural Archaeology
1994(1)
[10] Zhong Ren. Questions on ancient agriculture on lower Huai River. Agricultural Archaeology 1996(3)
[11] Xiuling You. History of Chinese rice agriculture. p.48, China Agriculture Publishing
[12] Gang Liu. Yunnan theory of rice origin is hard to prove. Yo-Ichiro Sato抯 origin of rice. Agricultural
Archaeology (3) 1994
[13] Xiangkun Wang. Conference notes of rice sites in Jiahu, Henan Priovince. Agricultural Archaeology 1994(3)
Baozhang Chen Carbonized rice Jiahu, Henan Province and its preliminary study. Agricultural Archaeology 1995(3)
[14] Luojiajiao Archaeology Team, Excavation report of Luojiajiao site, Tongxiang. Journal of Zhejiang Institute of
Material Culture and Archaeology, Material Culture Publisher, 1981
[15] Jixiong Zhou. Survey Report of Ancient Rice on mid and lower Yangtze River. Yunnan Agricultural
Technology 1981(6)
[16] Shengxiang Tang, Yo-Ichiro Sato & Weijie Yu. Finding of common wild rice in Hemudu carbonized rice.
Agricultural Archaeology 1994(3)