PLANT BREEDING 



183 



A B 



FIG. 157. Kernels of corn with high and with 

 low percentage of proteins 



A, high proteins, R, low proteins; p, horny layer, 

 consisting largely of proteins; s, white starchy 

 portion; e, embryo. After Bulletin 87, Univer- 

 sity of Illinois Agricultural Experiment Station 



Greatly increased care in its selection would probably at once 

 add more than $100,000,000 to the annual value of our corn 



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, 

 jw), and in the embryo; 

 the starch is mainly 

 found in the white, 

 floury part of the en- 

 dosperm () ; and the 

 oil is nearly all in the 

 embryo (?). 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 com with small 

 embryos a crop poor 

 in oiL 



Fio. 158. Kernels of corn with high and with 

 low percentage of oil 



A,Ai, cross section and face view of high-oil 

 kernels; B,Bi, cross section and face view of 

 1< >\v -oil kernels; c, 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 #7, Univer- 

 sity of Illinois Agricultural Experiment Station 



