A PLANTSMAN'S DETECTIVE STORY FRONTISPIECE. In Japan the skin of an orange called the Yuzu is widely used as a seasoning for cooked foods, and the extracted juice serves as a condiment, much as we use vinegar. The Yuzu is found semi-wild in southern Japan, and was long supposed to have been indigenous to that region. Among the many plants discovered by Frank Meyer in China was a wild orange which he called the Kansu orange, after the province of Central China in which it was found. Plants of this orange were raised in the greenhouses of the United States Department of Agriculture at Washington, and they were found to be surprisingly like the plants of the Yuzu growing there. Examination of Meyer's photographs and botanic material revealed the interesting fact that the Yuzu and the Kansu orange were identical, thus establishing the interesting fact that this useful Japanese fruit had been imported from China a great many years ago. This is the field photograph made by Meyer of the fruit of the Kansu orange. (See text, p. 245.) Downloaded from https://academic.oup.com/jhered/article-abstract/13/6/243/766907 by University of Durham user on 12 March 2018 CITRUS FRUITS OF JAPAN With Notes on Their History and the Origin of Varieties through Bud Variation1 TYOZABURO TANAKA Office of Crop Physiology and Breeding Investigations, U. S. Department of Agriculture - HEN the citrus fruits of Japan THE SATSUMA ORANGE Ware discussed, attention should be The leading orange grown in Japan called to the fact that orange is a kind of mandarin, Unshii Mikan, culture is one of the leading industries called the Satsuma orange in the of my country, producing fruit of ex- United States. This variety forms cellent quality and delicious flavor, nearly seven-tenths of our entire orange with an annual return of more than crop. The fruit of the Satsuma differs fifteen million dollars. Other fruits, from the King orange in its soft, thin, like persimmons, plums, apples, rind of a bright orange color, and in its peaches, sandpears, and cherries are extremely sweet pulp. The leaves of cultivated extensively, but none of the Satsuma are very large and droop- them rivals the orange, thanks to the ing, with the petiole devoid of con- climatic conditions of the island, which spicuous marginal wings. From com- throughout a large part of central and mon tangerines the Satsuma orange southern Japan seem more favorable is easily distinguished by the absence to orange culture than to any other of the scarlet or vermillion tinge which fruit industry. characterizes the rind of the tangerines. In consequence of the utilization of The Satsuma also is distinguished by flat areas for rice plantations, oranges the well developed calyx-lobes of its are mostly planted on the slopes of flowers and in its very fine-grained, hills, the sides of which are terraced melting pulp, which is of good keeping on a great scale, using heavy stone walls quality. to retain the soil. This orange is now raised in the The operations of planting, cultiva- United States, principally in Alabama tion, fertilization, picking, hauling, and and other Gulf States, the Satsuma packing, are all carried on by hand, orchards in the Mobile Bay District without the aid of heavy machinery. alone covering an area of about 12,000 The fruits are shipped to markets and acres. Its future is highly promising,, to centers of distribution by railway owing to the favorable climatic condi- or by boat. tions of the region into which it has Systematic methods of selling have been introduced, and also to the exis- developed in recent years in many tence of well organized business regions, and large packing houses and methods for handling the fruit. To storage plants are constructed either by the more efficient development of the individuals or by cooperative associa- Satsuma orange industry in this coun- tions of farmers. Within recent years try the Office of Crop Physiology and the exportation of citrus fruits to the Breeding Investigations is now direct- United States and Canada has been ing some attention, endeavoring espe- carried on under strict Government cially to introduce improved strains of inspection, with every precaution varieties into actual cultivation. against the dissemination of injurious insects and fungus diseases; but owing NATSU-DAIDAI, A LARGE SUMMER to our own excellent home market, the ORANGE export trade has not developed into an The second important orange of important enterprise. Japan is the Natsu-daidai. This is a 1 Read before the 160th Regular Meeting of the Botanical Society of Washington, at the Cosmos Club, May 2, 1922. Downloaded from https://academic.oup.com/jhered/article-abstract/13/6/243/766907 by University of Durham user on 12 March 2018 FRUITS OF THE WASE ORANGE FIGURE 1. These oranges were bo.ught in the Kobi market, Japan, on the third of November, 1919. They were forwarded to Washington where they arrived December the fifth, and this photograph was taken one month later. This was at least two months after they had been picked, during which time they had been shipped half way around the globe. The fine condition they were still in when photographed testifies to the remarkable keeping qualities of this variety. (See text, p. 251.) Photograph by E. L. Crandall. Downloaded from https://academic.oup.com/jhered/article-abstract/13/6/243/766907 by University of Durham user on 12 March 2018 Tanaka: Citrus Fruits of Japan 245 large summer orange about the size Besides these well-known kinds of and shape of a grapefruit; but it differs oranges, a number of local varieties or from the grapefruit in its more pitted fancy fruits are to be noticed, for in- skin, which is of a deep lemon-yellow, stance Anado and Tengu, attractive and in its coarse-grained, slightly for its red skin, but with rather insipid bitter pulp, which matures in late soft pulp; Naruto and Sambo, yellow spring. It is inferior in quality to a skin oranges of late maturing, with good grapefruit, but its extremely hardy good flavor; Koji, and Suruga-ynkd, nature and its resistance to citrus very early maturing small fruits of ex- canker are appreciated by growers, tremely smooth surface; Keraji Mikan as well as its admirable sturdiness of Kikai island, with very early matur- which enables it to withstand rough ing and extremely fragrant yellow treatment. fruit, Hyilga Natsumikan, with very late-maturing and very juicy medium- THE WASHINGTON NAVEL ORANGE sized fruits. The third important variety of orange is the Washington navel orange A MYSTERY SOLVED THROUGH A which was first imported into Japan in PLANT INTRODUCTION 1891. It was absolutely new to the Mention should be made of an orange Japanese growers when it was first highly esteemed for seasoning cooked introduced, and much attention has food, that is Yuzn, first called Citrus been paid to the development of the Jonos, by Siebold, in his Synopsis navel orange industry, but owing to the Plantarum Oeconomicarum, published humid atmosphere and lower temper- in 1830. This plant grows semi-wild, ature, it was found not to do so well in southern Japan, but is commonly as in southern California. Recently planted in the yards of farm houses for Japanese farmers have learned a special its fruit. The peel is highly aromatic, method of treating the plant, which and for flavoring cooked dishes and checks its vegetative overgrowth and soup or fish it is superior to lemons or increases fruiting by means of severe limes. The juice is used extensively in pruning or dwarfing, like the treatment the place of vinegar for seasoning raw of lemon trees in Italy. The good food and salads. Two hybrid varieties keeping quality of the fruit made it of Yuzu, Yuko and Sudachi, are ex- especially desirable, and the Japanese tensively cultivated in Shikoku Island were loath to give up its cultivation. for vinegar substitutes and also for Other kinds of sweet oranges are manufacturing citric acid. plentifully produced in the southern In 1915, Frank N. Meyer, the great part of the Kyushu Island ; but they do agricultural explorer of the U. S. Dept. not reach the central markets, from of Agriculture, found a wild orange which native pummelos and shaddocks in Kansu, China, which he imported are also absent. Over two hundred into this country under the provi- varieties of sweet oranges and pumme- sional name "Kansu Orange." After a los are estimated to exist in Japan close comparison of a green house proper, and a number of promising plant of the Kansu orange with the shaddocks, like Hirado, Egami, or Yuzu, together with an examination of Ogami, are of sufficient importance to Meyer's photographs and notes, the be multiplied for economic cultivation. writer found the two to be identical, A very prolific mandarin called Yat- thereby proving this extremely useful sushiro is often found in cultivation orange to be of Chinese origin. and the common China mandarin, The seeds of Yuzu are sometimes called Kishti Mikan, or Kinokuni in used for raising stock plants for the this country, is more or less extensively Satsuma orange, and it is believed by grown. Kunembo, a variety of the the farmers that plants grafted on King orange, is also commonly raised Yuzu stock live longer and behave in southern provinces. better than those grafted on Trifoliate Downloaded from https://academic.oup.com/jhered/article-abstract/13/6/243/766907 by University of Durham user on 12 March 2018 246 The Journal of Heredity orange under certain local conditions, extensively manufactured by proprie- especially on hill-top situations where tary medicine corporations and con- the available surface soil is apt to be spicuously advertised on signboards very thin.