Production, uses and cultivars of common buckwheat in Japan: An overview

Review article / pregledni znanstveni članek doi:10.14720/aas.2018.111.2.23 Production, uses and cultivars of common buckwheat in Japan: An overview Seisuke MOTONISHI1, Sakio TSUTSUI1, Tetsuo MIKAMI1* Received April 07, 2018; accepted September 17, 2018. Delo je prispelo 07. aprila 2018, sprejeto 17. septembra 2018. ABSTRACT IZVLEČEK Common buckwheat (Fagopyrum esculentum Moench) has attracted much attention due to its high nutritional value and medicinal properties. The crop has a long history of cultivation in Japan, and today, it is used mostly for manufacturing soba noodles which are quite popular in Japanese cuisine. Cultivation of common buckwheat in the country decreased gradually until the 1970’s, but has started to increase again in recent years. In this paper, we provide an overview of common buckwheat production in Japan with emphasis on the agronomic characteristics of representative Japanese cultivars and landraces. PRIDELAVA, UPORABA IN SORTE NAVADNE AJDE NA JAPONSKEM: PREGLED Key words: agronomic characteristics; breeding; common buckwheat; cultivar; genetic diversity; landrace; soba noodles Navadna ajda (Fagopyrum esculentum Moench) je pritegnila veliko pozornosti zaradi svoje velike hranilne vrednosti in zdravilnih lastnosti. Poljščina ima dolgo zgodovino gojenja na Japonskem in se danes največ uporablja za izdelavo “soba” rezancev, ki so zelo popularni v japonski kuhinji. Gojenje navadne ajde je v državi postopoma upadalo do sedemdesetih let prejšnjega stoletja, a je začelo v zadnjih letih spet naraščati. V prispevku je podan pregled pridelave navadne ajde na Japonskem s poudarkom na agronomskih lastnostih reprezentativnih japonskih sort in lokalnih zvrsti. Ključne besede: navadna ajda; agronomske lastnosti; žlahtnenje; sorta; genetska raznolikost; lokalne zvrsti; soba rezanci 1 INTRODUCTION Common buckwheat (Fagopyrum esculentum Moench), a member of the Polygonaceae family, has been widely grown for human consumption in Japan (Mazza, 1988; Ohnishi, 1988; Kishima et al., 1995; Murai & Ohnishi, 1996). The crop is not a cereal, but its fruits are expediently classified among the cereal grains because of their similar usage. In fact, buckwheat flour is commonly employed in combination with wheat flour to prepare buckwheat noodles (soba noodles), a popular Japanese dish. The history of buckwheat cultivation goes back to very ancient times in Asia (Murai & Ohnishi, 1996; Jacquemart et al., 2012). It is now broadly accepted that common buckwheat was initially domesticated in the northwest part of the Yunnan province in China (Murai & Ohnishi, 1996). This crop subsequently spread to Asian countries through two main routes (Murai & Ohnishi, 1996). The first route crossed the Himalayan 1 region and Tibet, and the second ended up in Japan through Northern China. Available evidence suggests that common buckwheat was introduced into Japan via the Korean peninsula from China (Nagatomo, 1984; Ohnishi, 1995; Murai & Ohnishi, 1996). The crop became popular primarily due to its ability to grow well on marginal, infertile land as well as its rapid growth habit. When buckwheat first appeared in records in Japan in the 8th century, it had already been cultivated extensively as a catch crop (Shinoda, 1978; Murai & Ohnishi, 1996). Although numerous local buckwheat landraces were grown in Japan at one time, common buckwheat culture in this country is currently dominated by only a small number of cultivars (http://www.tokusanshubyo.or.jp/jouhoushi/tokusanshu byo-26.pdf). In this paper, we review literature to provide an overview of common buckwheat production Hokkaido Agricultural Laboratory for Business Development, Eniwa, 061-1405, Japan *Corresponding author: Acta agriculturae Slovenica, 111 - 2, september 2018 str. 511 - 517 Seisuke MOTONISHI et al. in Japan. Emphasis is placed on the agronomic characteristics of main Japanese cultivars and landraces. The expectation is that the synthesized information from this review will be useful for researchers and other stakeholders interested in the common buckwheat crop in Japan. 2 COMMERCIAL PRODUCTION According to FAO statistics, the world buckwheat production in 2016 was approximately 2,396,000 metric tonnes (FAO, 2017). Russia and China were the largest producers, collectively accounting for ca. 65 % of global production that year. Japan ranked tenth in total buckwheat production (FAO, 2017). In Japan, buckwheat production reached a maximum (139,000 tonnes from 165,000 hectares) in 1907 (Suzuki, 2003). Thereafter, it continuously declined until the 1970’s (e.g., 18,000 tonnes from 18,000 hectares in 1975), because a number of farmers shifted their acreage from lower-yielding buckwheat to higheryielding crops such as rice (Suzuki, 2003). In recent years, however, buckwheat acreage and yield have started to increase again. As shown in Table 1, average production per year, from 2012 to 2016 inclusive, was ca. 34,500 tonnes (MAFF, 2017). This recovery tendency is undoubtedly due to the Japanese government subsidies to farmers who grow buckwheat, with the aim of decreasing the amount of excessively produced rice. It should also be added that Japan imports 65-75 % of its domestic demand, mostly from China and the United States (MAFF, 2017). Table 1: Production and cultivation area of buckwheat in Japan. Source: MAFF. (2017) Cultivation area (ha) Total harvest (t) 2012 61,000 44,600 2013 61,400 33,400 2014 59,900 31,100 2015 58,200 34,800 2016 60,600 28,500 3 USES Although the small leaves and shoots are also edible, common buckwheat fruits, generally considered as seeds are by far the most important for Japanese consumers. Harvested seeds are dehulled after drying, and the remaining part, called groats, is ground into flour. As mentioned above, buckwheat flour has traditionally been used in the preparation of soba noodles. The noodles play a major role in Japanese cuisine and are easily available in dried form in supermarkets throughout the country. Soba noodle dishes are served either cold with dipping sauce, or in hot broth as noodle soup. Common buckwheat is also processed to various valueadded products such as cakes, tea, beer and other local alcoholic beverages. The crop produces good quality of honey, whereas several buckwheat extracts are utilized for pharmacological and dietetics purposes (Bavec et al., 2002; Jacquemart et al., 2012; Kreft et al., 2016). In particular, flavonoids (mainly rutin and quercetin), Dchiro-inositol and proteins derived from buckwheat are in increasing demand, due to their biological and physiological activities including anti-oxidant, antiinflammation and anti-hypertension properties (Jacquemart et al., 2012; Suzuki et al., 2012a; GiménezBastida & Zieliński, 2015; Kreft et al., 2016). 4 JAPANESE CULTIVARS Common buckwheat exhibits a floral dimorphism known as distyly: each individual plant in a given cultivated population bears either pin (long pistil and short stamens) (...truncated)