SPECULATION ON THE ORIGIN OF RICE AGRICULTURE

SUN, Sheng Ru

Political and Law Committee, Hanjiang County, Jiangsu Province, PR CHINA 225100.

(Agricultural Archaeology 1998(1):100-107. Scanned by K. Sui; formatted by G. Leir; trans/ed. by B. Gordon & Li Lin)

        The origin of rice agriculture is a significant research topic in the natural and social sciences, and a very hot subject for Chinese and foreign scholars.

        Many people depend on paddy rice as a main grain crop, China being the world's largest producer. Its vastness, rich resources and superb history have made paddy rice >40% of all grain output, with the most acreage. Paddy rice production holds a pivotal position.

        Rice is an important constituent in agricultural origins, including both plant and animal husbandry. It is far earlier than recorded history, and gives modern researchers enormous difficulty on its origin, but has been strengthened by swift growth in natural sciences. Multi-disciplinary, multi-levelled and multi-angled research has clearly outlined rice origin.

        Modern archaeology has pioneered applications to ancient culture, including satellite remote sensing, C14 dating, thermoluminescence and tree-ring dating. Analysis of carbonized seed, pollen, phytoliths, etc., apply to ancient plants, giving archaeology new techniques like genetics, physics, chemistry, Co60 beam processing of common wild rice (CMR) seed; esterase and peroxidase analysis to differentiate CWR, indica and japonica; chloroplast DNA restriction enzyme for wild and cultivated rice evolution; SEM technology on carbonized rice for microstructure, etc. Modern genetics opened new areas in rice origins. Classical literature, Palaeolithic studies, palaoecology, anthropology, sociology, history, geography, etc., epitomize the multi-disciplinary approach to agricultural origins, especially cultivated rice.

        Humans branched from apes >3 million years ago, and after long exposure, harmonized with the natural environment in the dawn of prehistory. Modern science and technology may take us to the moon, but still depend on earth resources as backup. It is impossible to picture this vitality without people transforming the environment by scientifically using natural resources.

        Pre-agriculturalists were part of nature in a stage of ignorance; gathering, fishing and hunting birds and beasts, drinking their blood, using vegetable fiber and feather clothing instead of wool or silk [1]. Their survival forced them to think, providing experience in natural resource use. When huge Late Pleistocene environmental change extinguished some species, hunter-gatherers limited to berries, birds, animals, fish & shrimp innocently turned to plant stems, tubers, roots and seeds, the first step in agricultural origins, including rice.

        Research on rice origin carefully examines the broader field of natural and social growth. The 7000 year-old bone plow at Hemudu site as one of the earliest paddy cultivation tools fill one's mind, as do its wood mortars and pestles for rice processing, while pottery shows a long-standing wine brewing technology. Wood house balustrades were fastened with mortise and tenon joints. Potsherds depicting the pig not only show esthetic appeal but sculpture, giving knowledge of art history. Henan Province Wuyang's Jia Lake site has 7 full bone flutes not only depicting ancient culture but rewriting certain chapters of musical history. [p.100] 8000 year-old spinning and weaving was done with rotating round perforated stone spindle whorls and needles with 1 mm holes. Faunal and pollen analysis, palaeoclimatology and palaeoecology give needed data in all rice sites, some of which have been converted to museums, enriching travel for young visitors and providing vivid teaching material in their patriotic education. Research on cultivated rice origin not only broadens our agricultural history, but inspires our national spirit and brings honour to our culture, lifting self-confidence in China, with cohesive forces rushing to the new century. Jiangxi Communist Party Committee secretary Huiguo Su's Agricultural Archaeology, Broad and Deep at the 2nd International Symposium on Agricultural Archaeology is not only encouraging, but a significant affirmation and scientific summary.

        The world has two cultivated rice types: one originating in west African Nigeria, and now limited to Niger Basin; another in Asia, including China and East and South Asia.

        India scholars thought Asian rice originated in the east Indian Jiebou area, while 1960's Japanese scholars accepted the area SE of the Himalayas near Darjeeling. In the 1970's, Dubu Zhongshi suggested Assam-Yunnan because it is neither low nor damp, rice's origin supposedly in rough mountains. But Manila's International Rice Research Institute's Taiwan scholar Deci Zhang suggested a west Himalayan belt-shaped source that spread to Yunnan, Guangxi and south Guangdong, then to north Vietnam, Laos and north Burma.[2]

        Chinese research on cultivated rice origin covers three stages:

        First stage: Pre-1970's rice origin research began with famous agronomist Ding Ying who discovered wild rice in 1926 in east Guangzhou's Xiniuwei Marsh. In 1933, his Nurturing a New Guangdong Rice from Wild Rice outlined cultivated rice original habitat. For many years, he charted rice regions, selectively bred seed, cultivated rice, etc., systematically using ecology on cultivated rice origin, evolution and seed classification. In 1949, he suggested "an ancient South China Sea area" origin, repeated again in his 1957 article, but in August, 1961, he finished his China Paddy Rice Cultivation Study, mentioning Neolithic rice grain and plant remains in Yellow and Yangtze Valley potsherds; e.g.s, carbonized grain with Neolithic tools in Anhui's Wu River Haocheng Town site, Yangtze's Jing Mountain Qujialing and Shi River's Tianmen; burnt husks in Wuchang's Fangyin Dong, Wuxi's Xianlidun, Shidun, Anhui's Feidachendun, Nanjing's Miaoshan, Zhejiang Wuching's Xianshanyang and Hangzhou paddies and pottery rice impressions in SE Yunnan sites at Shizaishan, Jianchuan and Haimenkou. Early paddy rice cultivation in Yangtze and Yellow Valleys compare, but more Neolithic rice in the Pearl Basin need excavation. [3]

        Second stage: In the 1970-80's, research on cultivated rice origin broadened, with significant breakthroughs. From winter 1973 to spring 1974, the Zhejiang Province Luodiangong County East is Red commune began Neolithic excavation in Hemudu Village, research reaching a new stage. Hemudu's 10-20 cm to 30-40 cm thick (max. 70-80 cm), 400 sq. m level 4 grain, stalks and leaves kept their shape after carbonization. Their C14 age of 478090 BC or 7,000 years ago aroused enormous domestic and foreign interest. After the 3rd CCP Plenary Conference session 11, the party and nation experienced scientific liberation, agricultural history strongly uniting natural and social sciences, with Hemudu site an historically significant find. Hybrid vigor being a common biological phenomenon and paddy rice being self-pollenating, significent breakthroughs occurred on hybrid rice; e.g.s, (1) increasing hybrid seeds by chemically killing males (during meiosis, Daojiaoqing is sprayed to kill male), while pistil (female) fertility is normal. Then, the male parent is selected for superior advantage to hybridize the female. As main stem and sprouting times differ, a single spraying cannot kill all males, so we only obtain 70-80% hybrid seeds; (2) selecting one breed whose male organ is sterile based on genetic traits and calling it the male-sterile line. [p.101] As it is impossible to obtain hybrid offspring via the male-sterile line, it becomes extinct. There are simultaneous male-sterile b & r-lines. For superior hybrids, the Japanese found the male sterility phenomenon in 1927. A male-sterile line and superior hybrid research began in the 1950's in the Philippines, USA, India, South Korea and Soviet Union. In the 1970's intermediate stage, six male-sterile cytoplasms were found, but could not reproduce. [4] China's hybrid rice research began its mid-stage in the 1960's. Hunan's Qianyang Agricultural School found natural blossomless sterile pollen in 1964 and hybridized it with Nanguang into a C system. In 1970, Longping Yuan found male-sterile Yebai wild rice with aborted pollen in Ya County, Hainan Island. Yebai anther is thin, small, faint yellow and closed, with few individual coloured pollen. Cytologically and genetically, original Yebai was a natural hybrid of CWR and late-ripening local cultivated rice. In 1972, male-sterile line and hybrid research began with testing in 1974 using Yebai as female parent to cultivate a Yebai male-sterile line and corresponding b-line; e.g., 29 Nan #1 & 71-72. Their blend with International #24, #26 & #661forms a large hybrid root system, fast growth, large ears, broad compatibility, better nature and remarkably higher output [5]. Xiangchu He said at the 6th National Hybrid Rice Scientific Conference that a Hunan early and middle hybrid experimental paddy (800 acres in 1977 to 18,830,000 by 1975) used wild rice idioplasm, radically changing production and attracting party leaders. The Agricultural Academy of Science Wild Rice Resources Inspection Group coordinated research in 1978-1980 of several hundred units in 306 counties in 9 southern provinces; and (3) along with open policy reform, academics expanded international exchange, allowing foreign views. Now many academics cover rice origin areas:

        (1) Lower Yangtze River where Shilu Zhou first advocated cultivated rice origin in July, 1948, without academic response. Zongdian Min repeated him in 1979 after Hemudu excavation, with Jiangsu and Zhejiang Provinces as centres [6] supported by Wenming Yan's analysis of rice remains in 70 Neolithic sites. Yan's lower Yangtze origin followed [7] Shiting Yang's assertion that "ancient and modern natural conditions permitted wild and cultivated rice, as seen in ancient records and archaeological finds, especially SE to the coast as an origin area." [8]

        (2) Yunnan-Guizhou Plateau which Ziming Liu explained in 1975 using wild rice records as a Yangtze and Xi downriver spread to Hainan Island, Taiwan, etc. Other advocates are scholars Ningsheng Wang and Kunsheng Li, who stress its unique geography, complex climates and diverse ecotones. In 1979, famous agricultural historian Xiuling You's Discussion of Cultivated Rice Origin, Differentiation and Spread Based on Hemudu Excavated Rice said "paddy rice originated in the SW and gradually spread N in several ways: (1) N through central China to middle Yangtze; (2) N from SE coast; and (3) possibly from Yunnan to Yangtze River, splitting to Sichuan, Shanxi, etc., all more or less supported by archaeology". His Question of Tai Lake Rice Origin, Spread and Development is similar, with a Yunnan-Assam origin and spread down the Yangtze. As the challenge of Hemudu data forced further insight from You, he added "Japanese scholars Zuozuo Mugaoming and Dubu Zhongshi call it the Yangtze series, with rice entering Sichuan via Yangtze, then rapid spread NE to East China Sea (another via Xi River to Guangdong). The author thinks this spread is likely, but cannot explain a Hemudu origin."

        (3) Jiangnan (S China) as proposed by Enzheng Tong: "we conclude Asian cultivated rice originated south of the Yangtze, possibly Zhejiang's Hangzhou Bay, but likely at the latitude of S Yunnan, Guangdong & Guangxi." [10]. In 1989, he said the Early Neolithic Beiqiu cavern and open-air site was Hemudu culture or Early Neolithic. [11]

        (4) Lower Yellow River where Jiangzhe Li's Research on Dafei Cultivated Rice says rice originated on the common border of N Jiangsu and S Shandong, Hebei and Henan 7-8,000 years ago [12]. This caused uneasiness because it lacked scholarship and there are many centers of origin [p.102].

        Third stage. The late 1980's to present saw significant breakthroughs when Chinese and foreign scholars focussed on rice origin, symbolized in 1988 by Hunan's Li County Pengtoushan site, where C14 paddy rice dates of 9100120 and 8200120 years [13] provoked new theories:

        (1) Middle Yangtze River. Anping Pei lists reasons why "middle Yangtze paddy rice origin is likely": (a) Pengtoushan not only has China's but the world's earliest rice; (b) Early Neolithic carbonized husks are common in SW Shanxi's Lijia Village culture, Hubei's Chengbeixi culture, NW Dongting Lake's Pengtoushan culture, Zaoshi lower level culture, extending to Tangjia lower level and Dingjiagang level 1. While not as rich as Hemudu, their remains are earlier; (c) Hemudu agriculture is rich, but Pengtoushan agriculture is undeveloped; and (d) 10,000 year-old impressions occur at middle Yangtze's Dongting Lake. Sufficient 2-3 level Palaeolithic open-air sites or Early Neolithic Qiuling level caverns have stone tools dating before humans moved to the plain edge in Late Palaeolithic. Here, our hunter-gatherer ancestors evolved to primitive agriculturalists, [14] bypassing refining stages. Later, Weisi clarified three conditions for agricultural origin, Xiangkun Wang suggesting four. Progress occurred when many scholars began accepting three standards for cultivated rice origin.

        Weisi's middle Yangtze origin, Xuqiu Zhang's and Daren Kuang's prehistoric origin and growth and Xuqiu Yan's brief analysis of Zhijiang's Guanmiaoshan culture heavily supported a middle Yangtze origin, as seen in China Agricultural History's (1996-3) research seminar.

        (2) Dongting Lake. Liu wrote "as modern excavation shows the world's earliest rice is in the 9000 year-old Pengtoushan site on Dongting Lake, Li County, Hunan, I think Dongting Lake is its origin. This is supported by ancient engravings, construction, pottery, grave types, sacrificial offerings in ashpits, primitive witchcraft, legends, records, etc. Existing data suggest ties between Pengtoushan and Dongting Lake." [15]

        (3) Huai Basin. In 1983-7, Henan Archaeological Institute found the Jia Lake site 22 km from the north end of its village, east Wuyang County, on the NW Yellow-Huai Plain. It is an important 5500 sq. m Peiligang culture site, with excavated tools in early, middle and late levels. In level 3 in spring 1991, Juzhong Zhang et al. found many paddy rice grains, husk impressions and phytoliths of a cultivated subspecies with leaning stem. Baozhang Chen then extrapolated from cultural ecology and archaeology that Huai Basin is an origin center, part of a larger subset on the middle and lower Yangtze [16] [17]. Chen's view was supported by Renzhong, Shalin Ma and Erping Ren in their 2nd Int. Symp. of Agricultural Archaeology paper Reinvestigation of Huai Basin Rice Origin which said "a Huai Basin origin is important and a source for rice passing east to Japan."

        In the 1990's, the cultivated rice origin question became multi-disciplinary, an academic situation where mutual interests bloomed and schools of thought contended, propelling research and enriching the history of agricultural science. Especially worthy were some brave scholars who abandoned and revised former views. At the 1st Int. Symp. on Agricultural Archaeology, Anping Pei said in his paper Dongting Lake Early Neolithic Agriculture "it is time for academics to discuss rice origin on the middle Yangtze's Dongting Lake..." i.e., disseminating its major role as a center of agricultural origin. [18]. Juzhong Zhang found 10 well preserved husk impressions in an oxidized Jia Lake soil block in 1991. He, Zhaochen Kong and Changjiang Liu introduced the possibility of a vast mid-south origin [p.103] in the Yangtze and Pearl Basins [19]. Later, Juzhong Zhang, Xiangkun Wang and Zongjun Cui introduced a central Huai Basin origin, tying Yangtze and Yellow Basins with south China [20]. Both views are alike in having river basin origins, but differ in scale, as south China far exceeds the Pearl Basin. It is noteworthy Anping Pei's Pengtoushan site has both China and the world's earliest rice, as he discretely admits "why he understands this...the middle and lower Yangtze not only have similar latitude and natural conditions, but Hemudu and Pengtoushan have similar environments. Hemudu rice agriculture also suggests ties with Early Pengtoushan culture. Rigorous research and scientific methods show the middle and lower Yangtze have the earliest cultivated rice" [21].

        Despite most archaeologists believing the oldest rice site represents its centre of origin, ancient cultivated rice has 4 requirements from the earliest wild rice domestication to continuous cultivation involving clans and tribes in their core area: (1) widespread wild rice in its ancient ecosystem; (2) contemporaneity of oldest cultivated rice and its wild ancestor; (3) continuous cultivation; (4) and quite large clan and tribal community. Each is expanded below:

        (1) Widespread wild rice in its ancient ecosystem. Wild rice occurs at 30-600 m elevation in an area east to Taiwan's Taoyuan Town (12015'E), west to Yunnan's Jinghong Town (10047`E), south to Hainan Island's Yanglan people's commune (1815'N), and north to Jiangxi's Dongxiang County (2814 ' N). Jiangsu's Lienyungang and Anhui's Chaohu also have wild rice, but agricultural change greatly varied its distribution from 10,000 year-old wild rice. Reclaimed wasteland, huge flatland change due to irrigation, water conservation, harvesting and improved rice varieties, as well as comprehensive social progress, greatly reduced wild rice area. Jia Lake and Hemudu wild rice powerfully depict ancient wild rice distribution not only between Jiangsu and Anhui, but its arrival in the river district.

        (2) Concurrent existence of oldest cultivated rice and its wild ancestor. Archaeologically, You Xiuling said "Hemudu ecologically was a bog", while Anping Pei said "the Early Neolithic Pengtoushan culture typesite is Hunan's Li County Pengtoushan, Hubei's Yidou County Beixi Village, North Zhicheng, etc." This culture centers on NW Dongting Lake with Hubei north of the Yangtze River, a boggy lake basin surrounded by mountains [22]. Quanxi Yang said "paddy rice excels here after silting". Baozhang Chen's analysis of Jia Lake site middle level, upper Huai River, said its "many aquatic plant phytoliths and pollen suggest bog expansion, a good environment for paddy rice growth." [23] There appears to be close environmental correlation between rice origin and bog ecology at this important rice origin site.

        (3) Continuous cultivation. The oldest cultivated rice wild ancestor depends on accurate dating. Widespread use of C14 began in 1949 with Chicago University Prof. W.F. Libby. Anping Pei has China's earliest Neolithic C14 date, despite the usual 100 year error (>1000 years in limestone areas). Pengtoushan site now has 4 published C14 dates on potsherds of 9100120 (BK87002), T11(4) of 8200120 (BK87050), T14(2) of 7815100 (BK89016) and T14(6) of 7945170 (BK89018). >8000 years is credible, with >1000 years time span. Jia Lake site has 3 C14 dates of 7960150, 7920150 & 7561125, with tree-ring correction to 8942-8338 years, or ca. 600 years in Jiangsu. Zhangjiagang Dongshan Village site has (8) tree-ring corrected cultural levels of 806060 years [24]. Hemudu site C14 dates are 6725140 and 6960100 years [p.104]. Dongshan Village age is younger than Pengtoushan and Jia Lake, but its scale and technology of rice and animal domestication suggest long growth. Enzheng Tong estimates it cannot be <2-3,000 years, with initial cultivation 9-10,000 years ago. Hunan's Dao County Shouyan Town- Baizhai Village's Yuchanyan Crag's T9 3B2 level and 3E level C14 ages correspond (8327 & 7911 years B.C.). As archaeological finds are often fortuitous, new discoveries in agricultural archaeology retain the possibility of continuous breakthroughs. I now think the lower limit of rice origin is 10,000 years ago.

        (4) Large clan and tribal community. Ancient people adapted to nature, hunting, fishing and gathering to counter hunger, a blood relationship of cooperating clan and tribe. Population rose 16-18,000 years ago when glaciation brought ecological change where people could not develop plants for food storage, creating deficits in dry cold winters and spring shortages. This enormous struggle for survival sparked innovation like animal domestication, and gathering and storing grain, beans, yams, water chestnut, lotus root and Gorgon fruit. To store and boil water for sanitation, people invented rough, thick, primitive pottery.

        Rice origin is widespread, particularly in low lake wild rice areas. Inadvertently, ancient people imitated nature after seeing wild rice sprouting and earing over the year; e.g., lake bog rice luxuriantly grew in the second year through accidental transplanting, inevitably advancing to cultivation. At first, it could not satisfy demand and was supplemented by hunting, fishing and gathering, whose remains occur in cavern sites with rough rice. Demand was alleviated by taking rough rice grain to new places, causing us to ponder fortuitous finds.

        Paddy rice became a staple with flat land, fertile soil, irrigation, weeding, complete farm tools and organized labour. Hunting, fishing and gathering supplemented the transition to rice culture and established a material base. Anping Pei says: "of 114 ancient rice finds, the middle and lower Yangtze River have 87 (76.3%); upper Yangtze 4 (3.5%); Yellow and Huai Basins 13 (11.4%); Liaodong Peninsula 1 (0.8%); and Guangdong-Guangxi, Fujian Province 9 (7.8%)." Of these, only 7-8 have rough rice remains, but it explains how many middle and lower Yangtze finds support widespread lengthy correlation between tribe and rice agriculture.

        Inevitably, research on rice origin involves indica and japonica, and early & late-ripening paddy, dryland, sticky and glutinous varieties, Ding Ying's Paddy Rice Cultivation Study being the best authority: "Evolutionarily, indica is wet, heat and sunlight-resistant and coherently weaker, with long narrow grain, short glume hair, rough leaf surface, etc., traits approaching wild rice and its relations. Thus, indica is likely the first domesticate to cultivated grain and basic to cultivated rice. Japonica is more drought and cold resistant, less sunlight resistant and coherently stronger, with short wide grain, long dense glume hair, woolly leaf blade, etc., very unlike wild rice and why indica evolved under different environmental conditions (mainly temperature) and chosen for cultivation." Anomalies developed in early and late-ripening varieties: "early season splitting from basic late ripening form, but under long cultivation." While dryland rices also developed anomalies the paddy variety is considered basic, and varied through human selection to cultivated sticky and glutinous varieties: "all wild rice is sticky, with domestication starting as basic sticky rice, but glutinous rice varied in sticky rice evolution." [26] For 30 years I affirmed this, but now seek advice.

        (1) Shengxiang Tang, Shaokai Min and Zuoteng Yangyilang describe japonica & indica subspecies evolution [p.105], stressing unclear earliest coexisting indica and japonica. Of four centers with 109 rough rice remains, "indica and japonica coexist in 9 places, japonica in 21 places, indica in 2 places, and indica and japonica unclear in 77 places". Difficultly identified carbonized indica and japonica grain impressions occur with Pengtoushan tools in oxidized soil. Wenxu Zhang and Anping Pei studied 8-9000 year-old Bashidang site rice bipeaked tubercles in Mengxi Town, Li County,: "if only length and width are compared it is indica, but more analysis is needed to assess japonica and CWR traits in its evolution." [27] Xiangkun Wang et al. said "Jia Lake ancient rice is mostly indica, but leans to japonica on phytoliths (49%), indica being only 22%. [28] Yuyao Hemudu site also is indica and japonica and similar coexisting CWR grain. Cultivated rice is pleomorphic, its wild ancestor perhaps having more types than modern cultivated rice. Xiangkun Wang et al. differentiated indica and japonica in CWR using isozyme, with leaning to japonica...but CWR also has indica". [29] While they compared domestic CWR 571 & foreign CWR 27 later than 10,000 year-old wild rice, it may explain that ancient CWR idioplasm may be more complex than now.

        Distinguishing between indica and japonica is unreliable in excavated carbonized rough rice and depends on grain; e.g., Hemudu rice L/W ratio is 2.62 vs. 2.38 in >3509 modern indica varieties. Using SEM and a computer study of 81 carbonized grains, Hemudu ancient rice is a late-ripening cultivated indica paddy subspecies leaning to japonica and coexisting with CWR. Paddy rice blossoms first as second tillers, then one ear and most upper stems where one stem opens, then tassel, the second opening later, then fertilization 8-10 days later, when endosperm growth begins. After 7-8 days, grain achieves max. length, 8-12 days max. width and 12-18 days max. size. Primitive production was heavy even in the earliest stages, with maturation impossible to differentiate, and full grain not a suitable proportion. After prolonged burial in carbonized soil, grain size changes, with length and width poorly comparable.

        Under plant growth, the leaf blade falls, leaving phytoliths in the soil whose silica motor cell has very stable physico-chemical properties used in botanical research in agricultural archaeology. It distinguishes paddy from other rice, while S-450 SEM analysis of bipeaked tubercles separate indica and japonica, allowing less than perfect technology on their origin.

        (2) Evolution of early and late ripening rices is poorly described academically, the latter a product of low latitude and limited sunshine. Early, medium and late ripening modern paddy rice grows on the Yangtze and lower and upper Yellow Rivers. Over the past 10,000 years, sunshine varied with frequent climatic change, but total duration was quite stable. Pengtoushan, Jia Lake and Hemudu ancient rice was certainly not late ripening.

        (3) Evolution of paddy, dryland and glutinous rices. From an origin perspective, primitive CWR's many gene paths evolved to paddy and sticky rice in different ecotones. Early farmers domesticated CWR on its recessive glutinous gene and had an expression for sticky rice. They performed endless colour and fragrance change until it was >99% glutinous only when they found a glutinous variety in the sticky rice community.

        Late 1990's multi-disciplinary research on cultivated rice origin had breakthroughs, their approximation showing the need for further inquiry under many academic questions and long endeavours. A strong fresh world climate is needed, with a knowledge of ancient clan and tribe as well as prehistoric rice agriculture with its full toolkit, corresponding culture, etc. Personally, we must invite world scholars for assistance on unconditional knowledge on such significant topics. [p.106]

Bibliography:

[1] (Book of Rites - Ritual transport).

[2] Dubu Zhongshi: (Asian rice origin and spread). Translated by Xiong Haitang & Ouyang Yigeng. Agricultural Archaeology 1988(2).

[3] Ding Ying (ed.): (China paddy rice cultivation study), Agriculture Publishing House, Oct. 1961 1st ed. 1964, Shanghai 2nd printing: pp. 16-20.

[4] Jiangsu Province Paddy Rice Cooperative Group: (Paddy rice superior seed blend - three to test supply in research situation, 1976 April. Offprint.

[5] Hunan Province Hybrid Rice Research Cooperative: (Domestic release of hybrid rice), Agriculture Publishing House, Hunan People's Publishing Agency, Dec., 1975 1st. ed; March, 1976, 2nd ed.

[6] Min, Zhongdian: (Research on China cultivated rice origins). Jiangsu Agricultural Science, 1979(1).

[7] Yan, Wenming: (New discussion of Chinese cultivated rice origin), Agricultural Archaeology, 1989(2):72- 83.

[8] Yang, Shiting: (Archaeological probe on the evolution and spread of Chinese cultivated rice), Agriculture History Research, 2nd ed., Agriculture Publishing House, 1982.

[9] You, Xiuling: (Rice archival collection). China Agriculture Science and Technology Publishing House, June, 1993 1st ed., pp. 22, 28, 29.

[10] Tong, Enzheng: (A thousand questions on SE Asian and Chinese agricultural origins), Agricultural Archaeology, 1984(2):28.

[11] Tong, Enzheng: (South China agricultural origin and its traits), Agricultural Archaeology, 1989(2):60.

[12] Li, Jiangzhe: (Research on rice origin), Agricultural Archaeology, 1986(2):232-247.

[13] Anping Pei: (Pengtoushan culture rice remains and prehistoric agriculture), Agricultural Archaeology, 1989 (2):102-108.

[14] Pei, Anping: (Discussion of Early Neolithic agriculture on the middle Yangtze River). Agricultural Archaeology, 1991(1):121-131.

[15] Liu, Zhiyi: (Question on cultivated rice origin), Agricultural Archaeology, 1994(3):54-70.

[16] Chen, Baozhang: (Origin of 8000 year-old Cultivated Rice in Henan's Jia Lake site), Agricultural Archaeology, 1999 (l):55-57.

[17] Chen, Baozhang: (Initial studies on excavated carbonized paddy rice in Henan's Jia Lake site). Agricultural Archaeology, 1995(3):94-95.

[18] Pei, Anping: (Research on the origin of Dongting Lake prehistoric agriculture), Agricultural Archaeology, 1993(1):23-43.

[19] Zhang, Juzhong; Kong, Zhaochen & Liu, Changjiang: (Wuyang prehistoric rice remains in the Huai area of the Yellow River), Agricultural Archaeology, 1994(1):68-75.

[20] Juzhong Zhang; Xiangkun Wang; Zongjun Cui & Wenhui Cui: (Discussion of origin and eastern spread of Chinese cultivated rice), (Special studies collection of Chinese cultivated rice origin and evolution), China Agricultural University Publishing House, Dec., 1996, 1st ed., pp.14-21.

[21] Pei, Anping: (Pengtoushan culture rice remains within Chinese prehistoric rice agriculture), Agricultural Archaeology, 1989(2):102-108.

[22] Yang, Quanxi: (Discussion of Yangzte source of early primitive agriculture). Agricultural Archaeology, 1997 (l):31-35.

[23] Chen, Baozhang & Zhang, Juzhong: (Discovery of 8,000 year-old rice remains and classical literature research on Henan's Jia Lake Neolithic site).

[24] Xiao, Jinye; Qian, Gonglin; Ping, Jinlong & Zhang & Zhaogen Ding: (Ancient paddy rice phytoliths in Jiangsu Province Zhangjia Dongshan Village site), Agricultural Archaeology, 1994 (3) 98-100.

[25] Pei, Anping: (Discussion of rice origin and eastern spread). Quote from paper abstract in 2nd Int. Symp. on Agricultural Archaeology, p. 70.

[26] Ding Ying (ed.): (China paddy rice cultivation study). Agriculture Publishing House. In Oct., 1961, 1st ed., in March, 1964 Shanghai 2nd printing. pp. 23-28.

[27] Zhang, Wenxu & Anping Pei: (Excavated rough rice research at Bashidang site, Mengxi Town, Li County, Hunan). (Special studies on cultivated rice origin and evolution), China Agricultural University Publishers, December, 1996, 1st ed., p. 53.