CORN BREEDING 147 



hill ; and (2) so as to avoid injured and very small grains, 

 which would either fail to germinate or else cause the 

 young plants produced from them to grow off slowly. 



134. Grading the seed grains. — When extreme care is 

 taken to get all kernels of as nearly a uniform size as pos- 

 sible, in preparation for machine planting, each ear, after 

 being " nubbed " and " tipped," may be shelled sepa- 

 rately into a pan, and the resulting grain grouped into 

 kernels of three different sizes or shapes. This is more 

 conveniently done by shelling all nubbed and tipped ears 

 together and then separating the grains into three sizes by 

 passing them through a series of sieves with meshes of 

 different sizes. 



135. Effects of change of climate. — Corn brought 

 into the South from a cooler climate acquires year by year 

 in its new home greater height of stalk and later maturity. 

 With many highly improved varieties the grains apparently 

 become shorter and the number of rows may be reduced. 



As a rule, varieties from the corn-belt are not adapted to 

 the cotton-belt. They mature too early, make a smaller 

 yield of grain and stover than native varieties, and the 

 grain is often unmarketable, being weevil-eaten and 

 chaffy. 



Among the relatively few varieties from the corn-belt which 

 have in a few experiments shown fair yields of grain are Boone 

 County White and St. Charles White. Even these afford a better 

 grade of grain when the date of planting is rather late. 



In the region just north of the cotton-belt, the Western varieties 

 are nearer an equality with the native kinds. 



As a general rule, the best seed corn is that produced in nearly 

 the same latitude where it is to be grown. Usually corn of 

 Southern varieties produced south of the Ohio and Potomac 



