92 SOUTH ERN FIELD CROPS 



Many corn-breeders in the Northern States prefer that 

 the circumference of the ear at one third the distance from 

 the butt be three fourths the length of the ear. However, 

 the best proportions of an ear cannot be regarded as having 

 been determined for Southern varieties (Fig. 38). 



The Corn Grain or Kernel 



92. Shape. — The kernel of corn varies greatly in shape 

 and size with the different races of corn. There are even 

 great differences within the same variety and on the 

 different parts of the same ear. In the dent varieties, 

 practically all of the grains are flattened and somewhat 

 wedge-shaped, their smallest diameter being the one 

 parallel to the cob. Sturtevant found that in each of the 

 races of corn there are grains of three different subtypes ; — 



Subtype A, grain broader than deep ; 

 Subtjrpe B, grain as broad as deep ; 

 Subtype C, grain much deeper than broad. 



The typical grain in the most popular dent varieties has 

 the last shape; that is, it is much deeper or longer than 

 broad. 



93. The structure of the grain. — The gTain is made up 

 of a number of parts having distinct functions and separate 

 origins. As a means of simplification, these are here 

 grouped into three parts : — 



(1) the chit, germ, or embryo ; 



(2) the endosperm, or main l)ulk of the grain ; 



(3) the seed coats or l>ran. 



The embryo, or germ, is situated at the cob end of the 



