Tanaka: Citrus Fruits of Japan 



251 



which will behave as Mendelian domi- 

 nants. For instance, the hairiness of 

 of the ovary, the trifoliate form of the 

 leaves, and the existence of oil in the 

 pulp vesicles are in many cases Mendel- 

 ian dominants in crosses between the 

 trifoliate and other kinds of oranges. 

 The strong aromatic substance in the 

 rind of the Yiczu is also inherited with- 

 out much reduction by its offspring. 

 Wedge-shaped seeds and the well- 

 developed marginal wings on the peti- 

 oles of the leaves of pummeloes are 

 also handed down in varying degrees 

 to their descendants, and in add tion to 

 these, other dominant characters could 

 be enumerated. 



It is difficult, however, to explain the 

 origin of some of the characters which 

 make their appearance, as the absence 

 of seed in the Satsuma and the Wash- 

 ington navel orange. In the fiowers of 

 these oranges the male or staminate 

 organs are absolutely abortive, and 

 sometimes the female or pistillate 

 organ lacks the function of fertiliza- 

 tion. Vegetative nucellar tissue may 

 develop into the embryo without the 

 intervention of spores. This phenome- 

 non is generally called apogamy. The 

 seed thus formed when planted pro- 

 duces a plant exactly like the female 

 parent, whether it has been subjected 

 to cross-pollination or not.'^ A great 

 many plants produce seed by apogamy, 

 and all efforts to obtain hybrids by 

 cross pollinating them are ineffective. 

 Hybridization, therefore, cannot be the 

 only way to create new^ horticultural 

 varieties. In the Satsuma orange 

 there are several distinct groups or 

 sections, which differ from one another, 

 in some cases by the habit of the tree, 

 in others in the shape and size of the 

 leaves, in others in the time of ripening 

 the fruit, or perhaps in the appearance 

 of the fruit itself. 



THE WASE SATSUMA 



One group, called Ikeda, has numer- 

 ous small leaves and round fruits; 

 another called Owari, has larger leaves 



and flat fruits. From the latter is 

 segregated a strain with very large 

 leaves, and large, flat fruits. This is 

 generally called, by the Japanese 

 Kairyo, or improved Unshu. Another 

 striking variety, of promising eco- 

 nomic value, is the Wasc, first found 

 in the village of Aoe on Kyushu Island, 

 about twenty years ago, and now rank- 

 ing highest among all the oranges in 

 the market. The discovery of the Wase 

 orange was just an accident, but its 

 development into an important indus- 

 try was due to the keen business mind 

 of the Japanese farmer. Just how these 

 different varieties originated is not 

 known; but one thing is quite certain, 

 they are not of hybrid origin 



With the encouragement and help of 

 Mr. Walter T. Swingle, I took up the 

 study of citrus fruits in the hope of 

 securing the best type of large-fruiting, 

 early-maturing strains of the Satsuma 

 orange in Japan, which might prove of 

 value to growers in the Gulf states of 

 this country. In the American mar- 

 kets, as everybody knows, fruit is very 

 scarce from October 1st to November 

 15th; if ordinary varieties of Satsuma 

 are raised, the markets of this season 

 can partly be supplied by fruit from 

 the groves of Alabama. In 1920 the 

 first carload of Satsumas was shipped 

 as early as November 11th. During the 

 last year it was possible to ship this 

 fruit as early as October 23, using 

 artificial methods of curing. There still 

 remains a period of 20 days when 

 oranges are very scarce in the American 

 market. In this connection attention is 

 called to the fact that Japanese citrus 

 growers ship the fruit of Wase oranges 

 as early as September 20. 



Wase is a very distinct fruit, char- 

 acterized by large round form, ex- 

 tremely thin, polished rind, and very 

 abundant coarsely grained pulp (see Fig. 

 1). Its leaves, petioles, dormant buds, 

 flower-buds and calyx characters are 

 quite different from all other strains of 

 Satsuma, so that it may well be re- 

 garded as a good botanical variety. 



3 Swingle, W. T. and T. R. Robixsox. 

 April, 1922. 



A New Tangelo. Journal of Heredity XII: 151-153, 



