A STUDY OF FACTORS INFLUENCING THE YIELD OF POTATOES 1197 



ADAPTATION AND YIELD OF VARIETIES 



The crop survey offers one of the best means of determining the relative 

 merits of potato varieties for a given locality. Too often the experiment 

 stations have made generalized recommendations solely on the basis of 

 the performance of a few strains tested for only a few years at the station 

 grounds. A correct knowledge of the adaptability of various types and 

 varieties to given soil and climatic conditions can be obtained only by 

 cooperative controlled tests under varying conditions, or by a crop survey of 

 the performance of the varieties growing over a wide area with diverse condi- 

 tions. Nearly every state experiment station in the United States has at 

 some time conducted a yield test of potato varieties, the results of which are 

 to be found in the published literature. These results are in most cases of 

 very local significance and pertain only to the strains of seed that were 

 available for the test. Because of the wide variation in yield of the dif- 

 ferent strains of a given variety, no absolute recommendations for any 

 variety should be made on the basis of such tests. A comparison by survey 

 methods of the average yields of strains of the varieties within a region, 

 furnishes the best criterion of the merits of such varieties for that region. 

 Stuart (1915) has classified the standard American varieties into groups 

 containing varieties similar in tuber and foliage characters. It is now well 

 known that the varieties within each group conform fairly closely to one 

 another in. their adaptation to specific soil and climatic conditions. This 

 has made it possible to determine the type or group of varieties best adapted 

 to certain regions. It remains, then, only to choose high-yielding strains 

 of standard varieties within this group. The status of varieties within 

 each of the surveyed areas has been studied on this basis. Varieties and 

 types have been tabulated in the order of their extent of production in 

 each region. 



Potato varieties on Long Island 



Of the four regions surveyed, Long Island presented the greatest varietal 

 standardization by growing the fewest varieties and the fewest types. 

 Growers in this region are convinced that varieties of the Rural group 

 yield less, are poorer in quality, and are less popular in the New York 

 market, than varieties of the Green Mountain, or white-sprout, type. 

 Generally speaking, for the medium late crop, only varieties of the Green 

 Mountain group are raised on Long Island, and the early varieties for 

 this region are chosen from the Cobbler, the Early Ohio, the Rose, and 

 the Triumph groups (table 34). 



Altho Green Mountain was only one of several varieties of this group 

 grown in the three years from 1911 to 1913 inclusive, its popularity is shown 

 by the fact that two-thirds of the average total acreage during this period 

 was given to this variety. Irish Cobbler was the leading early variety 

 produced, and most of the acreage of this variety was grown in Nassau 



