Herodotus, the Greek historian, described radish as one of the most important crops in ancient Egypt and radishes are depicted on pyramid walls.
Recent studies indicate three independent domestication events that resulted in the black-skinned Spanish radish and two other distinct groups. One group is geographically restricted to Asia and shows more diversity than cultivated radish from the Mediterranean region (the second group) and wild radish types. This implies that Asian cultivated radish cannot be traced back to European cultivated forms that spread to Asia, but might have originated from a still unknown wild species that is different from the wild ancestor of European cultivated radish.
Today, radishes are grown throughout the world. Different societies prefer to use as food different parts of the radish plant including roots, leaves, sprouts, seed pods and oil from seeds. World production of radish roots is estimated at 7 million tonnes per year, about 2% of the total world production of vegetables. Radish is an important crop and food in China, Japan, Korea and Yemen.
The early domestication and selection of radishes led to significant variation in size, color and taste. Small-rooted radishes are grown in temperate regions of the world and harvested throughout the year. Larger-rooted cultivars such as Chinese radish are predominant in East and Southeast Asia. The cultivated radishes have several wild relatives such as R. raphanistrum and its subspecies.
Pistrick (1987) divided cultivated radishes into three groups:
- convar. oleifera (Raphanus sativus var. oleiformis), also called R. sativus Leaf Radish Group: oilseed and fodder radishes, grown in Southeast Asia and in Europe for leaf fodder and as green manure.
- convar. caudatus (Raphanus sativus var. caudatus), also known as R. sativus Rat-Tailed Radish Group: grown for its edible immature green or purple seed pods and leaves. This type is grown primarily in Southeast Asia.
- convar. sativus (Raphanus sativus var. sativus), also known as R. sativus Small Radish Group: all forms have edible roots, leaves and germinated radish sprouts, with many different varieties but generally of the small type.
Raphanus sativus var. niger, also known as R. sativus Chinese Radish Group, with the common names Chinese radish, Japanese radish, and Oriental radish is recognized as a fourth cultivated group.
Many older varieties of radish are no longer favoured because consumption patterns and preferences have changed. Furthermore, radish needs vernalization over winter to initiate flowering and is an outcrosser, making it more expensive for farmers to produce seeds than to buy seeds at the market. As a result, radish landraces and varieties have been replaced by new, modern varieties and are at risk of extinction. Wild radish species are threatened by ecological, climatic and human factors, or are already extinct. For example, there is no wild radish species in China although the crop has been recorded in ancient Chinese texts. Radish conservation is essential for the preservation of its diversity and to help people use crop diversity efficiently and sustainably to meet future challenges.
Major radish collections
It is estimated that more than 10,000 accessions of radish are conserved in genebanks around the globe. The largest collections are held in China (>2,000 accessions) and Japan (>1,000 accessions), accounting together for nearly one third of the total accessions conserved worldwide. Germany, Russia, United Kingdom and United States of America all have collections with more than 500 accessions. Many of those accessions are varieties and landraces. Wild relatives of radish are conserved mainly in genebanks in Australia, Germany and Spain.
Documents relevant to radish
- See references to radish on the Crop Genebank Knowledge Base
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 Biology Reporter, 29: 217–223
Pistrick K. 1987. Untersuchungen zur Systematik der Gattung Raphanus. Kulturpflanze 35:224–321.
Contributors: 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).
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 above experts.
Contact person: Qiu Yang, CAAS, China