Taro: Origins and Development
Basic Species Information
Taxonomy and Geographical Distribution
Colocasia esculenta (L.) Schott 1832, highly polymorphic (Plucknett 1983) with diverse wild-type and domesticated forms; cultivated in most tropical to warm-temperate regions of the world; possibly evolved in low mountains of Southeast Asia (vicinity of other wild species in mountains), now distributed in natural and disturbed habitats in subtropical to tropical regions from India to China, Australia, and Melanesia (the likely natural range, Matthews et al. 2017) and notably absent from Taiwan as a wild plant
C. formosana Hayata 1919, abundant and widespread in Taiwan; also present in Luzon; forms a morphologically homogeneous wild population and is not known in domesticated form; morphologically distinct, but minimally so, from wild C. esculenta (Matthews et al. 2015).
C. fallax, Schott 1859, wild in Himalaya
C. affinis Schott 1859, wild in mainland Southeast Asia, lower altitudes
C. lihengiae Long and Liu 2001 wild in mountains, northern Vietnam to Yunnan, China, and Northeast India
C. menglaensis Yin, Li, and Xu 2004, wild in mountains, northern Vietnam to Yunnan, China
C. yunnanensis Long and Cai 2006, wild in mountains, northern Vietnam to Yunnan, China
C. oresbia Hay 1996, wild on Mt. Kinabalu, Borneo.
C. gigantea (Blume) J. D. Hook. 1893, a leaf vegetable (petiole only) in Southeast to East Asia and especially popular in Vietnam; wild in karst landscapes of mainland Southeast Asia; a taxonomic and genetic outlier, distant from other Colocasia species
Major Domestication Traits
Reduction in acridity of raw tissue or an increase in the susceptibility of the acrid factor (an enzyme) to heat (cooking) or both.
Increase in the bulk of the starchy corms, with diverse associated changes in flavor and texture.
Distinctive green-white, purple-red, and yellow-orange colors in leaves, stolons, corms, and inflorescences; color variation aids cultivar identification and has aesthetic appeal in gardens and on plate.
Cold adaptation (many small side-corms) and day-length sensitivity in northern temperate cultivars.
Acridity helps protect against herbivores, reducing costs for cultivation and storage but increasing costs for processing and consumption. In some cultivars the reduction favors consumption of starchy corms and green vegetable parts (leaves, stolons); in others it may favor corms or green parts but not both. According to cultivar, the corms, side-corms, or leaves (blade or petiole) are main parts eaten; the stolons and spathes of some cultivars are also eaten. Throughout Southeast Asia, commensal wild taro populations with relatively low acridity are harvested as a green vegetable food and as a fodder for pig, making taro perhaps the most abundant green vegetable in the region.
Timing and Tracking Domestication
Cultivars in Eurasia are very ancient since taro is mentioned in ancient texts that date back to around 2000 years ago in both China and the eastern Mediterranean (Matthews 2006). Northern, temperate-adapted cultivars of taro may have originated in the northern margins of the natural range, in eastern Himalaya, where taro could breed, where triploids often appeared, and where farmers could select traits favorable to winter storage, spring propagation, and summer cultivation. The earliest association of taro with human settlement, from 10,000 years ago, has been found at Kuk Swamp in Papua New Guinea (Golson et al. 2017). In Papua New Guinea, taro used at early dates could have been a natural wild form or could have been undergoing domestication in response to changes in landscape management, cultivation methods, cooking methods, and food preferences.
Genetic studies have shown that taro cultivars are very diverse and form a number of distinct gene pools; the great diversity within diploid and triploid cultivars (2n = 28, 2n = 42) indicates domestication many times. Wild populations have not been studied in enough detail, or in enough places, to identify source regions and routes of movement. Since cultivars are carefully maintained as clones, some may be hundreds if not thousands of years old. Clones identified by the analysis of multi-locus genotypes have spread in many different directions, over vast distances, with trade and human migration (Chair et al. 2016). The antiquity of taro in Africa is much debated. Wild populations are not known there, and the crop was possibly introduced from multiple directions at different times: overland from West Asia, via the Indian Ocean from Southeast Asia, and via the Mediterranean Sea to North Africa and the Iberian Peninsula. Taro first reached the Caribbean and Central America as a food of slaves carried from West Africa.
- Matthews, P.J. 2006. Written records of taro in the eastern Mediterranean. In Proceedings of the fourth international congress of ethnobotany (ICEB 2005), ed. Z.F. Ertug, 419–426. Istanbul: Yayinlari.Google Scholar
- Matthews, P.J., V.D. Nguyen, D. Tandang, E.M. Agoo, and D.A. Madulid. 2015. Taxonomy and ethnobotany of Colocasia esculenta and C. formosana (Araceae): Implications for the evolution, natural range, and domestication of taro. Aroideana 38E: 153–176.Google Scholar
- Matthews, P.J., P.J. Lockhart, and I. Ahmed. 2017. Phylogeography, ethnobotany and linguistics: Issues arising from research on the natural and cultural history of taro, Colocasia esculenta (L.) Schott. Man in India 97: 353–380.Google Scholar
- Nguyen, V.D. 2005. New species of genus Colocasia (Araceae) for flora of Vietnam. VNU Journal of Science 11 (3): 54–56.Google Scholar
- Plucknett, D.L. 1983. Taxonomy of the genus Colocasia. In Taro: A review of Colocasia esculenta and its potentials, ed. J.-K. Wang, 14–19. Honolulu: University of Hawaii Press.Google Scholar
- Grimaldi, I.M. Taro across the oceans: Journeys of one of our oldest crops. In News from the past: Progress in African archaeobotany, Advances in archaeobotany, ed. U. Thanheiser, vol. 3, 67–82. Eelde: Barkhuis.Google Scholar
- Rao, V.R., P.J. Matthews, P.B. Eyzaguirre, and D. Hunter, eds. 2010. The global diversity of taro: Ethnobotany and conservation. Rome: Bioversity International.Google Scholar
- Rumphius, G. E. 2011. (17th C) The Ambonese herbal. Translated, annotated and introduced by E. M. Beekman. New Haven: Yale University Press.Google Scholar
- Spriggs, M., D.A. Addison, and P.J. Matthews, eds. 2012. Irrigated taro (Colocasia esculenta) in the Indo-Pacific: Biological, social and historical perspectives, 307–340. Osaka: National Museum of Ethnology.Google Scholar