642 PRACTICAL PROBLEMS 



strain will prosper even better in the hands of the farmer, and 

 thereby stand more chances of pleasing when put to the actual 

 test on the farm or in the orchard. Specious but faulty, is the 

 only correct verdict as to this position, though it may be main- 

 tained, perhaps, as to some special strains particularly sensi- 

 tive to high fertility. Improvement is what is aimed at by the 

 breeder, the production of better strains than before. On 

 this there are two significant points : 



1. The breeder will not know when he has succeeded in pro- 

 ducing an improvement unless the soil conditions are good 

 enough to permit full and complete development. 



2. All experience goes to show that plants are more variable 

 in soils of high fertility than in soils of low fertility. This is the 

 experience of De Vries, of Darwin, and, so far as is known to the 

 writer, of every plant breeder upon record. 



The object in all plant breeding is the production of improve- 

 ment. This is partly dependent upon fertility, and, in general, 

 plant-breeding operations will be most successful on lands of 

 maximum fertility. Some acclimatization may afterward be 

 necessary as to soil as well as to climate, but the latter is 

 involved in all plant breeding, and the former too, for that 

 matter, for no soil can be fairly representative of any very 

 great extent of territory. 



The balance of fertility. Much remains to be learned as to 

 the elements that should predominate in a fertile soil. In 

 general, nitrogen favors the growth of leaf and stem, but there 

 is much reason to believe that seed formation is intimately 

 related to the supply of phosphorus. The botanist will tell us 

 that Saprolegnia, for example, grows luxuriantly in beef extract 

 or peptone, but produces no reproductive organs ; grown in 

 nutrient solutions containing abundance of phosphorus, how- 

 ever, reproductive organs form readily, especially in the female. 



Without doubt much remains to be learned in the matter of 

 making up of soils most favorable for the production of desirable 

 variations in different classes of plants. In this matter of soil 

 fertility and cultural requirements let the plant breeder provide 

 maximum conditions, with no fear of evil consequences. If he 

 can succeed in producing a desirable variety by hook or by 



