Relation of Weather to Crops 51 



VARIETIES 



A Look into the Future 



Varieties of crops originate in two chief ways. A new variety- 

 is either the result of intentional breeding and improvement by 

 selection which had been carried on for a number of years, or it 

 comes into existence by chance — fortuitous variation, as the scientists 

 would say. In any event it is obvious that the characters on whose 

 account the variety is considered valuable to man are (in nearly 

 every case) first noticed at the place where the variety originates. 

 The new form is therefore preserved and propagated because it has 

 developed and displays some new and valuable characteristics under 

 the climatic and soil conditions existing at the place of its origin. 



The same variety, however, reacts very differently to the various 

 stimuli produced by different environments. Hence we arrive at 

 the commonly held and correct idea that each climatological area 

 has its own peculiar set of varieties which succeed best under its 

 own climatic and soil conditions. While these areas are only 

 vaguely defined and overlap in many cases, we know of very many 

 specific instances where differences in adaptation are unmistakable. 



As most of the climatic divisions of the continent have at least 

 some factors in common, the interchange and adoption of varieties 

 from one to the other have gone on simultaneously with the develop- 

 ment of local varieties. This procgiss is of course taking place in the 

 arid Southwest, of which Arizona and Sonora are a part, but with 

 less satisfactory results, perhaps, than anywhere else. Of the 

 seventy-two crops discussed in the succeeding pages, only about 

 thirty-five have a variety which succeeds as well in the arid vSouth- 

 west as elsewhere. Two reasons may be given to account for this 

 state of affairs. In the first place, the qjimate has little in common 

 with any other region, for here we find that lowest rainfall, lowest 

 relative humidity, and greatest percentage of sunshine occur 

 together; and this is true to the same extent of no other area of 

 North America. In the second place the agricultural activities are 

 so compaiatively new that local varieties have not had time to 

 develop. 



These remarks lead us to the conclusion that the arid Southwest, 

 of all the areas on the continent, is most in need of and will be most 

 benefited by local varieties of crops which flike the Arizona Ever- 

 bearing Strawberry) have been produced in the region'. Whether 

 thev are intentionally produced or accidentally discovered, they 



