46 LUTHER BURBANK 



Hardiness is often a sine qua non, particularly 

 with fruits intended for the new regions of the 

 Northwest, where the winters are extremely 

 cold. 



Then nearly all kinds of fruits are subject to 

 fungous diseases of some sort. These must be 

 combated by developing hardy, resistant varie- 

 ties. Advancement has already been made in 

 this direction; but much remains to be done. 

 The careful plant breeder will watch intently 

 his stock and promptly discard all susceptible 

 plants. 



It is in this way alone that such diseases can 

 ever be thoroughly and permanently conquered. 



In some parts of the United States the sun's 

 heat is too fierce and the air too dry for fruits 

 to thrive which have been accustomed to more 

 favorable conditions. 



For such regions varieties must be developed 

 which are low, compact growers, producing an 

 abundance of thick, leathery leaves, and fruit 

 that will not easily sunburn. Some of the east- 

 ern varieties, having become adapted to a moist 

 climate, are open growers, bearing rather thin, 

 delicate leaves. Such varieties are usually total 

 fa i lures when introduced in the arid Southwest. 



In developing a new fruit, the plant breeder 

 must not only meet the exacting demands of 



