The origins of edible brassicas Article Published Version Dixon, G. R. (2017) The origins of edible brassicas. Plantsman, 16 (3). pp. 180-185. ISSN 1477-5298 Available at http://centaur.reading.ac.uk/75821/ It is advisable to refer to the publisher’s version if you intend to cite from the work. See Guidance on citing . Publisher: The Royal Horticultural Society All outputs in CentAUR are protected by Intellectual Property Rights law, including copyright law. Copyright and IPR is retained by the creators or other copyright holders. Terms and conditions for use of this material are defined in the End User Agreement . www.reading.ac.uk/centaur CentAUR Central Archive at the University of Reading Reading’s research outputs online A native of sea-cliffs in the UK, wild cabbage (Brassica oleracea) is the ancestor of many edible brassicas ardeners’ plants result vegetables is full of fascinating sagas Enclosing gardens (the hortus from evolution in the wild, which are equally colourful as those conclusus of religion, art and legend) Gselection in cultivation and of ornamentals. Growing food protected crops from browsing most recently by scientifically supplies allowed the development animals and facilitated mankind’s directed breeding. The history of our of stable and civilized societies. move from hunter-gathering into permanent communities. Domestication of cereals, legumes and members of the cabbage family (Brassicaceae, also known as Cruciferae) The origins were major steps in mankind’s social evolution. The early Greek, Roman, Indian and Chinese writers recorded this development which has of edible continued into today’s societies. Brassicas provide edible leaves, flowers and roots that can be eaten fresh, cooked or processed. They brassicas also provide animal fodder and forage, permitting year-round meat Geoff Dixon Garden cabbage is perhaps the most familiar vegetable derived and milk production. Their proteins explores the origin of from Brassica oleracea and oils can be used in many edible products and for illumination and as vegetable brassicas industrial lubricants. For flavouring and discusses their they provide mustards and herbs. Many species are also used as flexibility and ornamentals in gardens, and as green diversity manures and composting crops. The Carol Sheppard / RHS Sheppard Carol tiny, rapidly reproducing rock cress, Arabidopsis thaliana, is widely used to study genetics and even in space research (Dixon 2006). 180 September 2017 PlantsmanThe Origins Wild B. napus is restricted in its ● Cabbage The popular image of Brassicas had primitive common range to northern Europe and vegetable brassicas is probably the ancestors that evolved around 24 Scandinavia. Brassica rapa colonized cabbage, epitomised in literary terms million years ago in the Horn of widely from the Fertile Crescent such as ‘cabbage garden’, often Africa and Arabian Peninsula (Arias into parts of Russia, China, synonymous with ‘vegetable garden’. et al. 2014). Their descendants southeast Asia and Japan (Tsunoda There are three groupings of migrated northwards into the Fertile et al. 1984). Both B. oleracea and cabbage: white-headed (B. oleracea Crescent, the region of early B. rapa possess similar genetic var. capitata f. alba), red-headed (f. agricultural development in what constituents and have taken parallel rubra) and Savoy (var. sabauda) is now parts of Egypt, Turkey, Syria, evolutionary pathways, resulting in (Nieuwhof 1969). Selection has Iraq and Iran. similarities between their respective favoured overlapping leaves with Two key species, Brassica oleracea crops (Cheng et al. 2016). spherical, flattened or conical, and B. rapa, and a product of their compact heads formed from natural hybridization, B. napus, are, European brassicas smooth, curled or savoyed leaves. respectively, the foundations for Variants of B. oleracea probably These were suited initially for most European, Oriental and some evolved both naturally and from climates and gardening niches across oilseed and edible brassicas. Brassica selection in domestication at several Europe, but eventually moving Mike Grant Mike napus contains the chromosome sets times and places. As a result, worldwide as convenience foods. of both B. oleracea and B. rapa relationships and naming can be (Hammer et al. 2013). Several similar, complex and confusing. Hence, for ● Kale This brassica probably naturally formed, fertile hybrids are practical breeding and gardening resembles most closely the earliest found in the brassica family, purposes a Dutch plant breeder, vegetable forms, and kale (B. oleracea highlighting its diversity and Hille Toxopeus, proposed using a var. acephala) is cultivated across flexibility. This natural hybridization horticulturally based nomenclature Europe. Residual populations of was initially unravelled by a Korean (Toxopeus 1974, Toxopeus et al. original wild kale are still found in horticultural botanist, U (1935). His 1979). This involved the use of Crimea. findings are supported by molecular subspecies and variety to classify Kale types were taken by Celtic studies that have emphasized the these crop types, guided by the tribes and later the Romans from the diversity and flexibility of both wild morphology of the edible parts Mediterranean and developed into and cultivated brassicas (Bonnema and their growth habits. His work hardy, reliable food sources for et al. 2011). supported earlier classifications migrating communities resulting in Wild populations of B. oleracea and suggested by Nieuwhof (1969) many forms. These include borecole its closely associated species colonized and Wellington & Quartley (1972). or curly kale, collard, marrow-stem cool, moist environments on the More recent molecular studies kale, palm-tree kale, Jersey kale, coasts of western Europe and the have supported the probability of Portuguese kale and thousand- Mediterranean approximately three selection pressures exerted by early headed kale (Monteiro & Williams million years ago (Arias et al. 2014). gardeners (Purugganan et al. 2000). 1989). Kale has achieved great popularity recently as an ingredient of healthy eating. Different types of kale ● Cauliflower Cauliflowers (B. oleracea var. botrytis) were known by Pliny, and cultivation of many types had spread widely across Europe by the late 15th century (Gray 1982). From these annual and biennial cauliflowers others were selected for temperate upland Tim Sandall / RHS Sandall Tim regions, while types suitable for hot and humid tropics were developed, especially in 19th century India. ➤ 181 HORTICULTURAL SCIENCE A classification that relates cauliflower types with their region of cultivation was proposed by Crisp (1982), specifying Northwest European biennials, Northern European annuals, Italian, Asian and Australian types. Recent breeding programmes have incorporated genes taken from ancient Italian landraces, producing an increased range of curd colours Dixon Geoff and shapes. Cauliflower ● Broccoli The relationships between cauliflower and broccoli / RHS Sheppard Carol (B. oleracea var. italica) were clarified by Massie et al. (1996) and by King (2003). Their research shows that Kohl rabi the cauliflower curd arose in southern Italy from a heading Oriental brassicas calabrese broccoli via an Selections of B. rapa are grown intermediate Sicilian crop type. extensively throughout Asia, Originally, the term broccoli showing a diversity which equals that (from Latin brachium, arm or branch) Dixon Geoff of European brassicas (Mizushima & described a range of edible floral Broccoli Tsunoda 1969). Originally, B. rapa shoots, including some from spread from the Fertile Crescent cabbages (Thompson 1976). The ● Kohlrabi The succulent, into Mongolia, China and then to term is now restricted to head types edible swollen-stemmed kohlrabi Japan. Much of its diversity probably carrying terminal inflorescences, (B. oleracea var. gongylodes) gained developed after its primitive types including multiple green (calabrese), popularity in central and southern reached China (Kumazawa 1965). purple or white flowers. Europe from the 15th century However, headed Chinese cabbages Green broccoli is a popular onwards. Those areas remain its now dominate cropping, with convenience vegetable and breeding European culinary stronghold, in adaptations for various climate for raised concentrations of contrast to the UK where it is little zones. Differentiating types of chemicals thought to be beneficial used. It is also well established in Asian vegetable is complicated by to health has increased its value. China and Vietnam. the diversity of local selections and names applied by Chinese, Japanese ● Brussels sprout Although known Brussels sprouts and other Asian growers. in medieval Europe, Brussels sprouts (B. oleracea var. gemmifera) became ● Pak choi This is perhaps the popular in 18th-century Brussels. most ancient of Oriental brassicas, Subsequently, French and English evolving in cultivation during the gardeners identified their value as 5th century AD. Pak choi (B. rapa winter vegetables. Locally adapted, subsp. chinensis) is grown widely open-pollinated land-races were throughout Asia, although Japanese selected for use in early autumn, gardeners still call it the ‘Chinese mid-season and late winter. vegetable’. Pak choi has also gained Japanese breeders produced F1 popularity in North America, hybrids in the mid 20th century, Dixon Geoff Australia and Europe, encouraged by providing breeding models for Asiatic migrants. Subspecies chinensis hybridizing