CITRUS FRUITS OF JAPAN 



With Notes on Their History and the Origin of Varieties through Bud Variation^ 



Tyozaruro Tanaka 

 Office of Crop Physiology and Breeding Investigations, U. S. Department 



of Agriculture 



WHEN the citrus fruits of Japan 

 are discussed, attention should be 

 called to the fact that orange 

 culture is one of the leading industries 

 of my country, producing fruit of ex- 

 cellent quality and delicious flavor, 

 with an annual return of more than 

 fifteen million dollars. Other fruits, 

 like persimmons, plum.s, apples, 

 peaches, sandpears, and cherries are 

 cultivated extensively, but none of 

 them rivals the orange, thanks to the 

 climatic conditions of the island, which 

 throughout a large part of central and 

 southern Japan seem more fa^•orable 

 to orange culture than to any other 

 fruit industry. 



In consequence of the utilization of 

 flat areas for rice plantations, oranges 

 are mostly planted on the slopes of 

 hills, the sides of which are terraced 

 on a great scale, using heavy stone walls 

 to retain the soil. 



The operations of planting, cultiva- 

 tion, fertilization, picking, hauling, and 

 packing, are all carried on by hand, 

 without the aid of heavy inachinery. 

 The fruits are shipped to markets and 

 to centers of distribution by railway 

 or by boat. 



.Systematic methods of selling have 

 developed in recent years in many 

 regions, and large packing houses and 

 storage plants are constructed either by 

 individuals or by cooperative associa- 

 tions of farmers. Within recent years 

 the exportation of citrus fruits to the 

 United States and Canada has been 

 carried on under strict Government 

 inspection, with every precaution 

 against the dissemination of injurious 

 insects and fungus diseases; but owing 

 to our own excellent home market, the 

 export trade has not developed into an 

 important enterprise. 



THE SATSUMA ORANGE 



The leading orange grown in Japan 

 is a kind of mandarin, Unshu Mikan, 

 called the Satsuma orange in the 

 United States. This variety forms 

 nearly seven-tenths of our entire orange 

 crop. The fruit of the Satsuma differs 

 from the King orange in its soft, thin, 

 rind of a bright orange color, and in its 

 extremely sweet pulp. The leaves of 

 the Satsuma are very large and droop- 

 ing, with the petiole devoid of con- 

 spicuous marginal wings. From com- 

 mon tangerines the Satsuma orange 

 is easily distinguished by the absence 

 of the scarlet or vermillion tinge which 

 characterizes the rind of the tangerines. 

 The Satsuma also is distinguished by 

 the well developed calyx-lobes of its 

 flowers and in its very fine-grained, 

 melting pulp, which is of good keeping 

 quality. 



This orange is now raised in the 

 United States, principally in Alabama 

 and other Gulf States, the Satsuma 

 orchards in the Mobile Bay District 

 alone covering an area of about 12,000 

 acres. Its future is highly promising, 

 owing to the favorable climatic condi- 

 tions of the region into which it has 

 been introduced, and also to the exis- 

 tence of well organized business 

 methods for handling the fruit. To 

 the more efficient development of the 

 Satsuma orange industry in this coun- 

 try the Office of Crop Physiology and 

 Breeding Investigations is now direct- 

 ing some attention, endeavoring espe- 

 cially to introduce improved strains of 

 varieties into actual cultivation. 



NATSU-DAIDAI, A LARGE SUMMER 

 ORANGE 



The second important orange of 

 Japan is the Natsu-daidai. This is a 



' Read before the 160th Regular Meeting of the Botanical Society of Washington, at the 

 Cosmos Club, May 2, 1922, 



H3 



