602 FUNDAMENTALS OF FRUIT PRODUCTION 



tree than the ordinary seedhng stocks develop. It is probable that more 

 of this kind of double working will be employed in the future. 



Blight resistant kinds of pear are coming into use as stock on 

 which the more susceptible but better flavored pears are worked. The 

 "Japanese" pear has been used for this purpose, with results varying 

 because several species have been imported under this name. Some 

 are comparatively tender, others are uninjured by a temperature of 

 -40°F. or even lower; some are comparatively susceptible to blight, others 

 practically immune. Among the more promising of these stocks are Pyrus 

 ussuriensis, P. ovoidea and P. calleryana.^^'^ The first of these is extremely 

 hardy; the last is comparatively hardy and is able to thrive in very wet 

 soils. There is no doubt that working of dessert varieties in limbs of these 

 trees will greatly decrease the labor and cost of fighting pear blight. 



Top working to insure hardiness in the trunk is discussed elsewhere. 

 It may be mentioned here, however, that the use of Rome Beauty trunks 

 for Gravenstein, the leading apple variety in the Sebastopol apple section 

 of California, has prevented the "sour-sap," which has been exceedingly 

 troublesome there. ^''^ 



An interesting possibility in the future of fruit growing in America 

 is top working for the development of a .better framework. Increasing 

 competition will ultimately tend toward the use of fruit of high quality. 

 Heretofore, varieties with good quality in fruit but weak growing habits 

 have been discarded; enhanced appreciation of quality is likely to force 

 the fruit grower to use such varieties whether he likes the tree or not. 

 With weak growing varieties he will likely resort to top working on frames 

 formed by more sturdy varieties. For this reason it is interesting to 

 note that in growing certain choice dessert varieties many European grow- 

 ers have followed this practice for a long time. Certain plums, as Petit 

 Mirabelle, which are weak growers, are worked into a sturdy interme- 

 diary such as Quetsche, Reine Claude de Bavay, St. Catherine, Krasensky 

 or Andre Leroy.^^ In Algeria the Japanese plums grow better when 

 top worked into peach limbs. The same process is followed with several 

 pears. Growers of choice apples appear to resort to similar devices for 

 Baltet lists numerous varieties as suitable intermediaries and states that 

 nurserymen grow certain varieties especially for this purpose. 



According to Lindemuth double worked apple trees have been in 

 great favor in Holland. A variety called "Sweet Pippin" is grafted 

 into seedhng stocks close to the ground and on this intermediary the 

 fruiting variety is worked at the height of the head. The sole reason 

 for this preference, it is said, is the thick trunk formed by the Sweet 

 Pippin, obviating the necessity of supporting the young tree during 

 its first few years by a stake. Since apple trees in northern Europe 

 are grown commonly with much higher heads than in the United States 

 this precise quality would be more important there. 



