Research Guides: Traditional Pacific Island Crops: Yam

Key Web Resources for Yam (Dioscorea spp.)

There are several species in the genus Dioscorea that are known as yams. The two most important ones in the Pacific are Dioscorea alata (greater yam, water yam) and Dioscorea esculenta (lesser yam, potato yam). Both of these species originated in southeast Asia and very early were carried by voyagers into the Western Pacific and brought D. alata as far east as Hawaii.

Yams continue to make an important contribution to nutrition and food security in most Pacific islands. In addition, Dioscorea alata is an important prestige food in Papua New Guinea, Fiji, Tonga, Vanuatu, Samoa and the Federated States of Micronesia.*

There are five other Dioscorea species that are grown to some extent in the Pacific today: D. nummularia, D. bulbifera, D. pentaphylla, D. rotundata, and D. trifida. (For information on the orange-fleshed tuber known as “yam” in the US, see the Sweet Potato section.)

*Regional Meeting on the Production of Root Crops, Suva, Fiji, 24-29 November 1975 : report . (1976).

IN THIS BOX are links to COMPREHENSIVE or OVERVIEW web resources on this crop.

For web resources on SPECIFIC TOPICS, select the appropriate category in the BOX BELOW.

Tropical Yams and Their Potential. Part l, Discorea esculenta
(Franklin W. Martin. 1974. Agriculture Handbook 457, USDA) "This is the first of several Agriculture Handbooks in which the major species of yams are individually treated…" This handbook covers botany, varieties, various aspects of cultivation, pests and diseases, and harvest and post-harvest information for Dioscorea esculenta. This is an historical document made available through the National Agricultural Library Digital Collections. Available as a PDF file.
Tropical Yams and Their Potential. Part 2, Dioscorea bulbifera
(Franklin W. Martin. 1974. Agriculture Handbook 466, USDA) "This is the second in a series of Agriculture Handbooks dealing with the major species of yams." This handbook covers botany, various aspects of cultivation, harvesting, preparation, and chemical composition of Dioscorea bulbifera. This is an historical document made available through the National Agricultural Library Digital Collections. Available as a PDF file.
Tropical Yams and Their Potential. Part 3, Dioscorea alata
(Franklin W. Martin. 1976. Agriculture Handbook 495, USDA) "This is the third of several Agriculture Handbooks in which the major species of yams are individually treated…" This handbook covers botany, varieties, various aspects of cultivation, pests and diseases, harvest and post-harvest information, preparation, and composition for Dioscorea alata. This is an historical document made available through the National Agricultural Library Digital Collections. Available as a PDF file.
Tropical Yams and Their Potential. Part 4, Dioscorea rotundata and Dioscorea cayenensis
(Franklin W. Martin and Sidki Sadik. 1977. Agriculture Handbook 502, USDA) "This is the fourth of several Agriculture Handbooks in which the major species of yams are individually treated…" This handbook covers botany, varieties, various aspects of cultivation, harvest and post-harvest information, preparation, and composition for Dioscorea rotundata and D. cayenensis. This is an historical document made available through the National Agricultural Library Digital Collections. Available as a PDF file.
Tropical Yams and Their Potential. Part 5, Dioscorea trifida
(Franklin W. Martin and Lucien Degras. 1978. Agriculture Handbook 522, USDA) "This is the fifth of several Agriculture Handbooks in which the major species of yams are individually treated…" This handbook covers botany, varieties, various aspects of cultivation, harvest and post-harvest information, preparation, and composition for Dioscorea trifida. This is an historical document made available through the National Agricultural Library Digital Collections. Available as a PDF file.
Tropical Yams and Their Potential. Part 6, Minor Cultivated Dioscorea Species
(Franklin W. Martin and Lucien Degras. 1978. Agriculture Handbook 538, USDA) "This is the last of several Agriculture Handbooks in which the major species of yams are individually treated…" This handbook covers botany, various aspects of cultivation, toxicity, preparation, and composition for less commonly cultivated Dioscorea species. This is an historical document made available through the National Agricultural Library Digital Collections. Available in HTML format and also as a PDF file.

Specific Topics for Yam (Dioscorea spp.)

Practical Guide to Identifying Yams: The Main Species of Dioscorea in the Pacific Islands
(Jill E. Wilson and Linda S. Hamilton. 1988. University of the South Pacific, Institute for Research, Extension and Training in Agriculture (IRETA), Publication 1/88, ) Field guide to identifying cultivated species of yams (Dioscorea); includes key with line drawings and species descriptions. (48 Kb PDF file)
Assessment of Yam Cultivar Diversity in Yap State, Federated States of Micronesia
(Murukesan V. Krishnapillai. 2005. IRFD World Forum on Small Island Developing States) "Yam (Dioscorea sp.) is one of the two main traditional food crops in Yap that shows a remarkable diversity of cultivars... The extent of distribution of various cultivars was studied in seven villages. Twenty-three cultivars of Dioscorea alata and seven cultivars of Dioscorea esculenta were recorded based on farmers’ perceptions and IPGRI descriptors."
Yam in vitro Gene Banking
(Dominique Dumet, Abigael Adeyemi, and Omena Ojuederie, International Institute of Tropical Agriculture (IITA)) This is a best practices manual describing the yam in vitro gene banking process set up by IITA. (700 Kb PDF file)
Regeneration Guidelines for Yam (Crop Genebank Knowledge Base)
(CGIAR) The information on this page was extracted from: G Rossel, C Espinoza, M Javier and D Tay. 2008. Regeneration Guidelines: Yam. In: Crop Specific Regeneration Guidelines. PDF file available for download.
Key Access and Utilization Descriptors for Yam Genetic Resources
Bioversity International, IITA. 2009) This list consists of an initial set of characterization and evaluation descriptors for yam utilization. (151 Kb PDF file)
Descriptors for Yam (Dioscorea spp.)
(IPGRI. 1997) Descriptors used for documenting and managing genebank accessions and germplasm collection. (336 Kb PDF file)
FAO / IBPGR Technical Guidelines for the Safe Movement of Yam Germplasm
(Brunt, A.A.; Jackson, G.V.H.; Frison, E.A., eds. 1989. International Plant Genetic Resources Institute) Provides "crop-specific technical guidelines that provide relevant information on disease indexing and other procedures that will help ensure phytosanitary safety when germplasm is moved internationally." (529 Kb PDF file)

Yam Nutrition and Soil Fertility Management in the Pacific
(Jane O’Sullivan, James Ernest, Marie Melteras, Siosiua Halavatau, Philip Holzknecht and Jimmy Risimeri. 2008. ACIAR) The Australian Centre for International Agricultural Research (ACIAR) funded this project with the overall objective to increase the efficiency and sustainability of yam production through improved crop nutrition. This report provides details on research undertaken by the project, characterization of nutritional disorders in yam species, and country-specific information on soil and farming system amendments for the improvement of yam production.
Yam Nutrition: Nutrient Disorders and Soil Fertility Management
(Jane N. O’Sullivan. 2010. ACIAR) "This book draws together what is currently known about the mineral nutrition of yams. Most of the information on nutrient deficiencies and toxicities has not been published elsewhere. It is intended as a useful reference for agronomists and extension personnel, and also researchers." (5.29 Mb PDF file)
Rapid Multiplication of Yams (Dioscorea spp.)
(Jill E. Wilson, Kim Des Rochers, and Carl I. Evensen. 1989. University of the South Pacific, Institute for Research, Extension and Training in Agriculture (IRETA), Publication 3/88, ) Explains minisett rapid multiplication for the production of yam (several Dioscorea species) planting stock; includes line drawings. (401 Kb PDF file)

The Pacific Islands Pest List Database
(Secretary of the Pacific Community) This database contains records of pests and diseases that are currently known to affect agriculture, forestry and the environment in Pacific Island countries and territories (PICTs). Country pest lists are currently available for Samoa, Tonga, Niue, French Polynesia, Fiji, American Samoa, Cook Islands, Vanuatu, New Caledonia, Solomon Islands, Papua New Guinea, FSM, Palau and Marshall Islands. The database can be also be searched by crop; use either English common name or botanical name. The database contains records for all of the crops covered by this Web site.
Report Document on Diagnosis of Banana, Yam and Other Diseases in Pohnpei
Scot C. Nelson and Flordeliza B. Javier. 2001. Cooperative Research and Extension, College of Micronesia - FSM) Reports on the identification of a fungal disease of banana, yam rust disease, and phytophthora fruit rot of breadfruit; includes many color photographs of disease symptoms. (1.7 Mb PDF file)
Viruses of Plants - Known Susceptibilities of Dioscoreaceae
(A.A. Brunt, K. Crabtree, et al. 1996. Plant Viruses Online) Includes data on host range; transmission and control; geographical distribution; physical, chemical and genomic properties; taxonomy and relationships; and selected literature references.

Traditional Post-harvest Technology of Perishable Tropical Staples
(Pamela A. Lancaster and D.G. Coursey. 1984. FAO Agricultural Services Bulletin No. 59) This Bulletin reviews the limited amount of information that has been recorded relating to the post-harvest technologies of the perishable, non-grain staple foods that have been developed in the traditional societies of the developing countries of the tropics. These foods are derived primarily from the tropical root crops cassava, yam, sweet potato and the various aroids; from fruit such as banana and breadfruit; and from the starches in pandanus and sago; includes references.
Yams - Post-Harvest Operations
(Linus U. Opara. 2003. Information Network on Post-harvest Operations (INPhO), FAO) Yams are second to cassava as the most important tropical root crop and are a staple food in many parts of Africa, Southeast Asia and the South Pacific. Yams are mainly grown for direct human consumption and are marketed as fresh produce in all the growing regions. The tubers can be stored for up to six months without refrigeration. (0.5 Mb PDF file)
Storage and Processing of Roots and Tubers in the Tropics
(Aliou Diop and D.J.B. Calverley. 1998. FAO) This publication addresses storage and processing issues of the principal root and tuber crops of the tropics: cassava (Manihot esculenta), yam (Dioscorea spp.), sweet potato (Ipomoea batatas), potato (Solanum spp.) and edible aroids (Colocasia spp. and Xanthosoma sagittifolium). It covers factors affecting storability, principles of storage, and specific handling, storage methods, and processing for these crops.
Careful Storage of Yams: Some Basic Principles to Reduce Losses
(Jill E. Wilson and Linda S. Hamilton. 1987. University of the South Pacific, Institute for Research, Extension and Training in Agriculture (IRETA), Publication No. 15/87) Descriptions of simple storage structures, sanitation principles, rat control techniques, tuber selection principles, and curing to reduce storage losses of yams; includes line drawings. (747 Kb PDF file)

Roots, Tubers, Plantains and Bananas in Human Nutrition
(O.L. Oke, J. Redhead and M.A. Hussain. 1990. FAO) This publication reviews the value of roots, tubers, plantains and bananas in human nutrition. It also includes information on toxins and antinutritional factors. The crops covered include bananas and plantains (Musa sp.), cassava (Manihot esculenta), sweet potato (Ipomoea batatas), cocoyam (taro - Colocasia and Xanthosoma), and yam (Dioscorea sp.). The book is intended for nutritionists, agriculturists, dieticians, community development workers, school teachers and economists. It includes some information on processing these crops.
The Pacific Islands Food Composition Tables, 2nd ed.
(Cecily Dignan, Barbara Burlingame, Shailesh Kumar and William Aalbersberg. 2004. FAO) Food tables for a large variety of foods consumed in Pacific Islands. There are 22 nutrients in the main body of the tables, which are presented in a fixed format for each record. The order of presentation is based on major nutrient categories and convention.
Chemistry of Tropical Root Crops: Significance for Nutrition and Agriculture in the Pacific
(Howard Bradbury and Warren D Holloway. 1987. ACIAR Monograph No. 6) This publication reports the results of a study on the chemical composition and nutritional status of Pacific root crops including cassava (Manihot esculenta), sweet potato (Ipomoea batatas), yams (Dioscorea sp.), giant taro (Alocasia macrorrhiza var. macrorrhiza), giant swamp taro (Cyrtosperma chamissonis), and the taros (Colcasia esculenta and Xanthosoma sagittifolium). It includes a literature review as well as the original data generated in the ACIAR project. (22.83 Mb PDF file)
Feedipedia: An On-line Encyclopedia of Animal Feeds
(FAO) Feedipedia is an open access information system on animal feed resources that provides information on nature, occurrence, chemical composition, nutritional value and safe use of nearly 1400 worldwide livestock feeds.

Yam: A Status Food (South Pacific foods leaflets; 14)
South Pacific Commission, 1990) This leaflet covers nutritional value, storage, preservation, and cooking; includes recipes.

Select Markets for Taro, Sweet Potato and Yam
(Grant Vinning. 2003. Rural Industries Research and Development Corporation) This report presents information concerning potential export markets in Japan and the U.S. for three Australian grown root crops: sweet potato, taro, and yam. It also presents information on the Australian production and marketing scene. It also examines some export competitors such as China for sweet potato and Fiji and Samoa for taro. (1.4 Mb PDF file)
International Agricultural Trade Statistics
(FAOSTAT) Figures are given for quantity and value of commodies imported/exported (in metric tonnes). International commodity prices are used to calculate the total value of each commodity produced by each country. Select "Countries" using the drop down menu and then use the drop down menu to select the crop product. (There may be statistics available for more than one product for a crop.) Country level statistics are available using the links in the left hand navigation bar.
International Agricultural Production Statistics
(FAOSTAT) Provides figures for area harvested, yield, and quantity produced (in metric tonnes)Use the drop down menu to select the crop. Country level statistics are available using the "Countries" drop down menu.
U.S. Census of Agriculture - 2007 Census Publications
(USDA, National Agricultural Statistics Service) The "Outlying Areas" section has links to the 2007 reports for Commonwealth of the Northern Mariana Islands, Guam, Puerto Rico, and the Virgin Islands. There are links to previous Census of Agriculture publications which also include American Samoa. Generally, the reports include harvest figures for banana and plantain, betel nut, breadfruit, cassava, coconut, sweet potato, taro, and yam.

Secretariat of the Pacific Community (SPC), Land Resources Division
Working in partnership with its 26 members and with regional and international agencies, SPC assists the people of the region by delivering a wide range of technical, research, educational and planning services. The Land Resources Division provides assistance and does research on a variety of Pacific crops including banana, breadfruit, cassava, kava, pandanus, sweet potato, taro and other aroids, and yam. Land Resources Division (LRD) has established an email based Helpdesk system to provide technical advisory support to Pacific Island Countries & Territories (PICTs).
International Institute of Tropical Agriculture (IITA) - Agricultural Research for Development in Africa
Research areas cover tropical agriculture, plant health, and crop improvement and management in the tropics. Crops covered include cassava, cowpea, maize, plantain/banana, soybean, and yam.

PubAg
(National Agricultural Library, USDA) PubAg is a portal to USDA-authored and other highly relevant agricultural research. At launch, it delivered over 40,000 full-text journal articles by USDA staff and includes nearly 450,000 citations. Open access; no login required.
ScholarSpace - UH Manoa
(University of Hawaii at Manoa Library) ScholarSpace is UH Manoa's institutional repository. It provides free Web access to many of the University's publications. It includes both legacy publications and current research papers, journal articles, books, and conference proceedings. All are available in full text as PDF files. Try using the Advanced Search and enter the English common name or the botanical name.
AGRICOLA: 1970 - present
(National Agricultural Library, USDA) Citations, most with abstracts, to journal articles, books, theses, technical reports, and other publications in agriculture and related areas such as nutrition, biotechnology, and botany. Use the Keyword Search and enter the English common name or the botanical name.
AGRIS: 1975 - present
(FAO) International database covering agricultural sciences and technology containing citations for conventional and non-conventional ("grey") literature. Search using the English common name or the botanical name.
PubMed (Medline): 1946 - present
(U.S. National Library of Medicine, NIH) Citations with abstracts for journal articles in biology and medicine including botany and nutrition. Citations may include links to free full-text content from PubMed Central and publisher web sites. Search using the English common name or the botanical name.
FAO Document Repository
(Food and Agriculture Organization of the United Nations) Searchable access to full-text electronic versions of FAO publications; covers topics such as crop and livestock production systems, hunger and food security, commodity markets, climate change, nutrition, fisheries, forests, and rural livelihoods.
Sorting Dioscorea Names - Multilingual Multiscript Plant Name Database
Snow Barlow. 2007. University of Melbourne) Lists approved botanical names and synonyms and provides common names in a number of languages.

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