The Pollination of Manihot esculenta (yuca) and It’s

Importance to Archeology: A Beginning Study

Elizabeth Georgian

Introduction

• Yuca belongs to the family Euphorbiacea and the genus Manihot

• Yuca is one of the world’s most productive crop plants in terms of calories

• There are two types of manioc: the bitter and the sweet

http://www.nationaalherbarium.nl/euphorbs/specM/Manihot.htm

Introduction continued

• Yuca is planted by use of stem cuttings• Most Amerindian cultivators plant

several different varieties of yuca• Why are there so many different

varieties of yuca, if the only method of planting is by use of stem cuttings?

Review of Pollination

http://dbs.umt.edu/courses/sci226/lab4_plantsanimals.htm

Review of Pollination continued

• Pollen from the stamen lands on the stigma

• The pollen grain conveys the genetic material down the style to the ovary

• After fertilization the ovule develops into a seed and the ovary develops into the surrounding fruit

Creating new varieties

• Amerindians have many different varieties of yuca

• Cloning is important for maintaining the stock of one variety

Creating new varieties continued

• New varieties of yuca are created through sexual reproduction

• Thus, when different varieties reproduce together, new varieties are created

• Some varieties will be superior and may continue to be cultivated through stem cuttings

• Other varieties will be inferior and will be lost

Seed dispersal

• Most varieties produce flowers which, after pollination, produce a fruit and three viable seeds (Elias et al 2000)

• The fruit dries in the sun and dehisces, sending the seeds flying to the ground

Seed dispersal continued

• Ants disperse the seeds which have been propelled to the ground

• The ants feed their larvae nutrients from the seed appendage (Elias and Mckey 2000)

• After used, the seed is discarded in a waste pile where it waits until the appropriate germination requirements are met

Spontaneous seedlings

• The spontaneous seedlings are not weeded by Amerindians

• If the spontaneous seedling produces tubers that are deemed desirable, the new variety will be propagated by stem cuttings

Archeology and Paleobotany• Paleobotanists work to recover, identify

and classify plant remains• Paleobotanists and archeologists could

work together to uncover more information about ancient yuca

Why is pollination important to archeology?

• Pollen can be found at archeological sites

• This can help determine where ancient manioc was located

Archeology and Pollen

• Manihot fossil pollen has been found at a number of sites

• A grain of pollen was found in the costal region of Tabasco, Mexico (Bartlett et al 1969)

• Pollen also was found in Panama (Dickau et al 2007)

What other methods could be employed to clarify the

relationships and unknown data on Manihot esculenta?

• Systematics• Microfossils• Macrofossils

Systematics• Systematics is the study of relationships

between species of plants• Systematics could help end some

confusion relating to relationships in the Manihot genus

Microfossils

• Microfossils are fossils that are microscopic

• Examples of microfossils include pollen, phytoliths and starch grains

Macrofossils

• Preserved remains of yuca and artifacts pointing to the domestication of yuca can be considered macrofossils

Remaining Questions

• What is the type of pollinator? Bird? Insect? Wind?

• What is the species of pollinator?• What are the systematic relationships of

the varieties?• What are the exact germination

requirements?

Acknowledgements

• I want to sincerely thank Dr. Robert Carneiro, without whom this great opportunity would not have arisen.

• I would also like to thank the Second Symposium of the Program for Molecular Archaeology, Sciences and Engineering Applied to Studies of the Past committee for welcoming me to their lovely campus and for graciously inviting me to this conference.

Bibliography• Arroyo-Kalin 2008 “Steps towards an ecology of landscape: a geoarcheological

approach to the study of anthropogenic dark earths in the central amazon region, Brazil.” Dissertation. University of Cambridge.

• Bartlett, Alexandra S., Elso S. Barghoorn, and Rainer Berger. 1969 “Fossil Maize from Panama.” Science, Vol. 165 (3891), pp. 389-390.

• Carneiro, Robert L. 1983 “The cultivation of manioc among the Kuikuru of the Upper Xingu.” In Adaptive Responses of Native Amazonians, ed. By Raymond B. Hames and William T. Vickers, pp. 65-111. Academic Press, New York.

• Dickau, Ruth, Anthony J. Ranere and Richard G. Cooke. 2007 “Starch grain evidence for the preceramic dispersals of maize and root crops into tropical dry and humid forests of Panama.” Proceedings of the National Academy of Sciences, Vol. 104, No. 9, pp. 365103656.

• Dufour, Darna. 1988 “Cyanide content of cassava (Manihot esculenta. Euphorbiaceae) cultivars used by Tukanoan Indians in Northwest Amazonia.” Economic Botany, Vol 42, pp.255-266.

• Elias, M. and D. McKey. 2000 “The unmanaged reproductive ecology of domesticated plants in traditional agroecosystems: an example involving cassava and a call for data.” Acta Oecologica, Vol. 21, No. 3, pp. 223-230.

• Elias, M., D. McKey, O. Panaud, M-C. Anstett and T. Robert. 2000 “Traditional management of cassava morphological and genetic diversity by the Makushi Amerindians (Guyana, South America): perspectives for on-farm conservation of crop genetic resources.” Euphytica, Sous presse.

Bibliography continued• Elias, M., L. Penet, P. Berolino, P. Vindry, D. McKey, O. Panaud and T. Robert

N.D. “Unmanaged sexual reproduction and the dynamics of genetic diversity of a vegetatively propagated crop plant, cassava (Manihot esculenta Crantz), in a traditional farming system. Molecular Ecology, in press.

• Murray, Kevin. Science 226. University of Montana-Missoula. <http://dbs.umt.edu/courses/sci226/lab4_plantsanimals.htm>

• Piperno D.R. 1990 “Aboriginal agriculture and land usage in the Amazon basin, Ecuador. Journal of Archaeological Science Vol. 17, pp.665-677.

• Piperno, D. R. 1998 “Paleoethnobotany in the Neotropics from microfossils: new insights into ancient plant use and agricultural origins in the tropical forest.” Journal of World Prehistory, Vol. 12, No. 4, pp. 393-449.

• Piperno, D.R. 2006 “Phytoliths: A comprehensive guide for archaeologists and paleoecologists. Altamira Press: Maryland.

• Ugent, Donald, Sheila Pozorski and Thomas Pozorski. 1986 “Archaeological Manioc (Manihot) from Coastal Peru.” Economic Botany, Vol. 40, No. 1, pp. 78-102.

• Van Welzen, P.C., Q.D. Nguyen and R.C.K. Chung “Manihot.” Nationaal Herbarium Nederland <http://www.nationaalherbarium.nl/euphorbs/specM/Manihot.htm>