PLANT BREEDING 
183 
Greatly increased care in its selection would probably at once 
add more than $100,000,000 to the annual value of our corn 
Fic. 157. Kernels of corn with high and with 
low percentage of proteins 
4, high proteins, B, low proteins; p, horny layer, 
consisting largely of proteins; s, white starchy 
portion; e, embryo. After Bulletin 87, Univer- 
sity of Dlinois Agricultural Experiment Station 
crop. The structure 
of the grain of corn, 
as shown by the dia- 
grams in figures 157 
and 158, is such that 
the relative amounts 
of proteins, starch, and 
oil can be roughly 
estimated by a me- 
chanical examination 
of the grain. This most important fact was discovered by 
Professor C. G. Hopkins, of the University of Illinois. The 
proteins are very largely stored in the horn-like part of the 
endosperm (fig. 157, 
j), and in the embryo: 
the starch is mainly 
found in the white, 
floury part of the en- 
dosperm (s); and the 
oil is nearly all in the 
embryo (e). If seed 
corn is chosen from 
ears with kernels in 
which the horn-like 
portion is highly devel- 
oped, the result will 
be a crop with a large 
percentage of proteins: 
seed corn with large 
embryos will yield a 
crop rich in oil, and 
seed corn with small 
embryos a crop poor 
in oil, 
Fie. 158. Kernels of corn with high and with 
low percentage of oil 
,4,, cross section and face view of high-oil 
kernels; B,B,, cross section and face view of 
low-oil kernels; e, embryo. Most of the oil (as well 
as a good deal of the proteins) is contained in the 
embryo, so that an embryo large in proportion to 
the size of the kernel means a high percentage 
of oil in the grain. After Bulletin 87, Univer- 
sity of Dlinois Agricultural Experiment Station 
