CHAPTER XXXI 

 CULTURE OF IRISH POTATOES 



CULTURAL methods differ so widely for local reasons that it would 

 not be practical to describe in detail the various methods in practice. 

 Only the most general principles of wide application can be 

 considered. 



Source of Seed. The degeneration of potatoes under hot sum- 

 mer climate has been pointed out. Wild potatoes grow in high 

 mountains where the summer temperature is cool, and cultivated 

 potatoes require the same conditions. 



In England, where the summer season is warm, it has long been 

 recognized that seed from Scotland was much more productive and 

 numerous experiments have proven this. The Vermont Station 1 

 in 1905 imported 13 varieties from England and Scotland and grew 

 them in Vermont for six years in succession. The results in yield 

 per acre were as follows : 



1905 1906 1907 1908 1909 1910 



English seed 27.5 54.9 88.4 86.9 103.5 169.5 



Scotch seed 82.3 128.3 236.7 159.2 143.1 170.5 



Per cent of differ- 

 ence 199.3 133.7 167.8 83.2 38.3 .6 



The first three years the difference was very great, but as they 

 were continually grown under one climate, the difference became 

 less until they yielded practically the same the sixth year. 



A very interesting demonstration of the principle was made at 

 the Ottawa Experiment Station in Canada. The climate here is 

 usually very favorable, and four varieties which were grown at the 

 station for sixteen years, 1890-1905, steadily increased in yield, as 

 shown by following data : 



1 Vermont Bulletin 172. 



271 



