Radish genetic resources
Contact person for Radish: Qiu Yang, CAAS, China
Contributors to this page: CAAS, China (Qiu Yang, Li Xixiang); Bioversity International, Italy (Imke Thormann, Ehsan Dulloo); CGN, Netherlands (Noortje Bas); IPK, Germany (Andreas Börner, Ulrike Lohwasser); AVRDC, Taiwan (Andreas Ebert); USDA, USA (Larry Robertson); NBPGR, India (Chitra Pandey); SASA, UK (George Campbell); University of Warwick, UK (Charlotte Allender).
Compilation of best practices
Information on current practices for genebank management of radish genetic resources was first gathered from literature and then validated and updated in collaboration with the following genebanks: CGN - Wageningen, IPK - Gatersleben; AVRDC-Taiwan, USDA Plant Genetic Resources Unit - USA, NGB - NBPGR - India, SASA - UK, WARGRU Warwick - UK.
Importance and origin
Radish (Raphanus sativus L.) is an anciently annual or biennial cultivated vegetable. It most likely originated in the area between the Mediterranean and the Caspian Sea (Crisp 1995). It may come from the wild radish in southwest China (Cheo et al. 1987). It is possible that radishes were domesticated in both Asia and Europe. According to Herodotus (c. 484-424 BC), radish was one of the important crops in ancient Egypt, as radish was depicted on the walls of the Pyramids about 4000 years ago. Cultivated radish and its uses were reported in China nearly 2000 years ago (Li 1989) and in Japan radishes were known some 1000 years ago (Crisp 1995).
Based on recent studies using chloroplast single sequence repeats (cpSSRs), Yamane et al. (2009) postulate three independent domestication events which include black Spanish radish and two distinct cpSSR haplotype groups. One of the haplotype groups is geographically restricted to Asia, presenting higher cpSSR diversity than cultivated radish from the Mediterranean region or wild radish types. This implies that Asian cultivated radish cannot be traced back to European cultivated forms which spread to Asia, but might have originated from a still unknown wild species that is different from the wild ancestor of European cultivated radish (Yamane et al. 2009).
Today, radishes are grown throughout the world. Different local people prefer to use various parts of the radish plants including roots, leaves, sprouts, seed pods and oil from seeds as their food according to their own custom. Radishes are low in calories and high in vitamin C, folate, and potassium. Radishes contain sulfurous compounds, such as sulforaphane, which have anti-cancer properties, and are expectorant.
The early domestication of radishes, evolutionary processes and human selection of preferred types have led to significant variations in size, color and taste of this vegetable crop. Among them, small-rooted radishes are grown in temperate regions of the world and harvested throughout the year (Crisp 1995). Larger-rooted cultivars such as Chinese radish are predominant in East and Southeast Asia (Schippers 2004).
World production of radish roots is estimated at 7 million t per year, about 2% of the total world production of vegetables (Schippers 2004). In China, Japan and Korea, as well as in Yemen, radish ranks high in importance (Schippers 2004).
Radish (Raphanus sativus L.) belongs to the Brassicaceae (alt. Cruciferae) family with chromosome numbers 2n = 2x = 18. The cultivated radishes have several wild relatives such as R. raphanistrum and its supbspecies landra (Moretti ex DC.) Bonnier & Layens, maritimus (Sm.) Thell., microcarpus (Lange) Thell., raphanistrum, rostratus (DC.) Thell.; and R. confusus (Greuter & Burdet) Al-Shehbaz & Warwick.
Pistrick (1987) divided cultivated radishes (Raphanus sativus L.) into three groups:
convar. oleifera (Raphanus sativus var. oleiformis Pers.), also called R. sativus Leaf Radish Group (Wiersema and León 1999), oilseed and fodder radishes, which are grown in Southeast Asia and in Europe for leaf fodder, and as green manure.
convar. caudatus (Raphanus sativus var. caudatus (L.) L. H. Bailey), also known as R. sativus Rat-Tailed Radish Group (Wiersema and León 1999) - the rat-tail radish (also known as mougri, radis serpent) grown for its edible immature green or purple seed pods and leaves. This type is grown in Southeast Asia.
convar. sativus (Raphanus sativus var. sativus), also known as R. sativus Small Radish Group (Wiersema and León 1999), where all forms are with edible roots, leaves and germinated radish sprouts, with many different varieties but generally of the small type (radish, small radish, turnip radish, petit rave).
Raphanus sativus L. var. niger J. Kern, also known as R. sativus Chinese Radish Group with the common names Chinese radish, Japanese radish, and Oriental radish are recognized by Wiersema and León (1999) as fourth cultivated group.
Radishes can be classified in different ways: small-rooted (sometimes referred to as var. radicula) and large-rooted types (including names such as var. nigra, niger, sinensis, acanthiformis or longipinnatus) based on root size; European, Chinese, Indian and Japanese based on geography; spring or summer radish and winter radish, Chinese radish (var. longipinnatus Bailey) and all-season radish (var. radiculus Pers.) based on the adaptation to growing seasons and regions (Zhu et al. 2008).
Radish is an important root and leafy vegetable throughout the world. The small-rooted and short-season type of radish is cultivated for salads and as fresh vegetable. The large-rooted type of radish is usually cooked, canned or pickled besides being eaten raw. The leaves and sprouts are used as salad or are cooked, too. The seed pods are cooked for soups in southwest China and Southeast Asia. People press seeds of Raphanus sativus to extract oil. Wild radish seeds contain up to 48 percent oil, which is not suitable for human consumption but has promise as a source of biofuel (http://en.wikipedia.org/wiki/Radish). Farmers also grow oil radishes to improve and fertilize the soil and as fodder. In traditional medicine, radishes are used as one of nonpoisonous materials to treat coughs, cancer, whooping cough, gastric discomfort, liver disorders, constipation, dyspepsia, gallbladder disorders, arthritis, gallstones, and kidney stones (Adams 2008).
References and further reading
Adams M. 2008. Radish. [online]. Available from: http://www.healingfoodreference.com/radish.html. Date accessed: 21 July 2009.
Cheo TY, Guo RL, Lan YZ, Lou LL, Kuan KC, An ZX . 1987. Angiospermae, Dicotyledoneae, Cruciferae. In: Cheo TY, editor. Flora Reipublicae Popularis Sinicae. Vol 33. Science Press, Beijing (China), pp 1-483.
Crisp P. 1995. Radish, Raphanus sativus (Cruciferae). In: Smartt J, Simmonds NW, editors. Evolution of crop plants. 2nd Edition, Longman Scientific & Technical, UK. pp. 86–89.
George RAT, Evans DR. 1981. A classification of winter radish cultivars. Euphytica, 30(2): 483-492
Kong Q, Li X, Xiang C, Wang H, Song J, Zhi H. 2011. Genetic Diversity of Radish (Raphanus sativus L.) Germplasm Resources Revealed by AFLP and RAPD Markers. Plant Molecular Biolology Reporter. DOI 10.1007/s11105-010-0228-7
Li S. 1989. The origin and resources of vegetable crops in China. International Symposium on Horticultural Germplasm, Cultivated and Wild; Beijing, China, Sept. 1988. Chinese Society for Horticultural Science, International Academic Publishers, Beijing, pp. 197-202.
Pistrick K. 1987. Untersuchungen zur Systematik der Gattung Raphanus. Kulturpflanze 35:224-321.
Radish [online]. Available from: http://en.wikipedia.org/wiki/Radish. Date accessed: 10 October 2009.
Schippers RR. 2004. Raphanus sativus L. [online] Record from Protabase. Grubben GJH, Denton OA, editors. PROTA (Plant Resources of Tropical Africa / Ressources végétales de l’Afrique tropicale), Wageningen, Netherlands. Available from: http://database.prota.org/search.htm. Date accessed: 22 January 2010.
Thormann I, Qiu Yang, Allender C, Bas N, Campbell G, Dulloo E, Ebert AW, Lohwasser U, Pandey C, Robertson LD, Spellman O. Development of best practices for ex situ conservation of radish germplasm in the context of the Crop Genebank Knowledge Base. Genetic Resources and Crop Evolution. Published online 17 October 2012. DOI 10.1007/s10722-012-9916-5. http://www.springerlink.com/content/eg71r166jq524363/
Wiersema, JH, León B. 1999. World Economic Plants – A Standard Reference. CRC Press, USA.
Yamagishi H, Terachi T. 2003. Multiple origins of cultivated radishes as evidenced by a comparison of the structural variations in mitochondrial DNA of Raphanus. Genome 46: 89–94
Yamane K, Lü N, Ohnishi O. 2009. Multiple origins and high genetic diversity of cultivated radish inferred from polymorphism in chloroplast simple sequence repeats. Breeding Science 59: 55–65
Zhu DW, Wang DB, Li XX. 2008. Chinese crops and wild relatives, vegetable crops volume (1). Beijing: Chinese Agricultural Press.