8 BULLETIN 307, U. S. DEPARTMENT OP AGRICULTURE. 



conditions, however, different varieties are affected in much the same 

 way; that is, differences between early and late varieties are in a 

 measure retained, whether maturity is delayed or hastened by growing 

 conditions. 



The varieties previously described are arranged in Table I in their 

 approximate order of earliness, as nearly as this could be judged from 

 all the tests conducted. The earliest varieties are placed first and the 

 latest varieties last in the table. The extreme range in time of 

 maturity is about 25 days. The earliest varieties require under 

 average conditions from 75 to 85 days, while the latest ones require 

 from 100 to 110 days to mature. 



For convenience of reference the varieties are divided into three 

 classes, designated as very early, early, and comparatively late. 

 There is a marked difference in the average time of maturity of these 

 classes, but the lines between classes are necessarily somewhat arbi- 

 trary; that is, the differences between the last varieties in one class 

 and the first varieties in the next class are not greater than the differ- 

 ence between varieties of the same class. 



Table I. — Corn varieties in the order of their earliness in reaching maturity. 



Class 1 . 



Class 2. 



Class 3. 



Very early varieties: 



Early varieties: 



Comparatively late varieties: 



Gehu Flint. 



Martens White Dent. 



North Platte Silver Mine. 



Northwestern Dent. 



U. S. Selection 133. 



North Platte Calico. 



Minnesota 23. 



Minnesota 13. 



IT. S. Selection 160. 



Brown County Yellow. 



Cassia County Flint. 





Ardmore Yellow. 



"White Australian. 





Mitchell Blue Flour. 



Swadley. 



Dakota Red Squaw. 

 Ninety-Day Disco. 

 Amber Flint. 

 Mitchell Calico. 

 Golden Glow. 

 Colorado Early Select. 

 Wisconsin 7. 





RESULTS OF TESTS OF VARIETIES. 



Tests of corn varieties have been conducted at several stations in 

 the north-central Great Plains area. Yields secured for each station 

 and year when a successful crop has been produced are shown in 

 Tables II to VII. These yields do not indicate what may usually 

 be expected in any locality in an average or normal season. They 

 more nearly represent what may be expected in favorable seasons 

 under good farming practice. 



Careful attention has been given to securing uniform conditions for 

 all varieties in each test, but no unusual or intensive methods of cul- 

 tivation or manuring have been employed. At all places where the 

 crop has depended upon the natural rainfall for moisture, total 

 failures or very low yields have resulted in some years. The results 

 indicate the behavior of different varieties under the same conditions. 



