The Bulletin. 29 



est yielders of shelled corn per acre of all the varieties thus far tested. 

 These, too, are all white varieties and are medium to medium late in 

 maturity. The best of the varieties tested at the western farm are 

 almost the same as for the east, but the order of prolificacy is somewhat 

 different. 



CORRELATION OF CHARACTERS OF VARIETIES OF CORN. 



One of the purposes of our detailed study of varieties of corn, exhib- 

 ited in Tables I, II, III and IV, is to ascertain what characters, bein? 

 mutually helpful and hence conducive of greater yields, may be expected 

 to be found combined in the same variety, and what ones, being gen- 

 erally antagonistic, seldom or never occur in the same plant or group 

 of plants. This knowledge is of the most fundamental importance in 

 the proper production of not only corn, but all other agricultural crops, 

 as one being familiar with these facts will be better enabled to origi- 

 nate, improve or select varieties best adapted to different localities, 

 soils and purposes. It is also felt that a more correct interpretation 

 can be placed on the results obtained in variety tests. 



In Table IV are brought together the average results of the work of 

 six years (1903-'04-'05-'06-'07-'08) at the Edgecombe and Iredell farms, 

 separately. From a detailed study of this table, supplemented by field 

 observation, the following tentative inductions are made with reference 

 to varieties of corn studied when they are grown under conditions of 

 soil and climate as represented by these two farms : 



Antagonistic Characters. — (1) Earliness in maturity, other things 

 being equal, is not generally conducive to large yields of grain and 

 stover. (2) L?rge-eared varieties usually have a low percentage of 

 grain to cob, and are as a rule less productive of shelled corn per acre. 

 (3) Ears with very small cob have poorly shaped kernels, and give a 

 small amount of shelled corn per ear, and vice versa. (4) Kernels of 

 low vitality do not tend to the growth of plants of maximum yields. 



Associated Characters. — (1) Earliness, other things being equal, 

 usually tends to high percentage of ear to stover, and vice versa, al- 

 though this ratio is more or less modified by season, soil, fertilization 

 and breeding. (2) Varieties producing two ears per stalk are generally 

 more productive of shelled corn per acre than those bearing only one 

 ear, although it may be a large one. (3) Medium maturity, other 

 things being equal, tends to increase yields per acre of grain. (4) 

 Small kernels usually possess low vitality. (5) Kernels with small 

 germs (chits) contain a small percentage of oil or fat. (6) Varieties 

 with good root and leaf development are usually the most resistant ones 

 to drought and disease and insect ravages. 



SELECTING SEED FOR IMPROVEMENT. 



In the improvement of corn by seed selection an endeavor should be 

 made to start with the best variety as ascertained by actual tests in 

 the field through a sufficient number of years to eliminate weather con- 

 ditions. It must be borne in mind that in all plant improvement the 

 same principles and practices that have been employed with such strik- 

 ing results in the improvement of the different breeds of animals must 

 be followed. 



