SELECTION FOR OIL AND PROTEIN 



469 



OIL AND PROTEIN IN CORN HARVESTED FROM THE MIXED OIL PLOT 



IN 1900. 



.LOW OIL SIDE 



HIGH OIL SIDE 



This data is considered very reliable, both kinds of corn having 

 been grown during the same season and in exactly the same soil, and 

 each individual sample whose composition is shown is a composite 

 sample representing many ears. The average difference in oil con- 

 tent between the high oil side and the low oil side is 1.97 per cent 

 oil, while the average difference in protein is .18 per cent. Consider- 

 ing the percentage of protein in the corn is twice as large as the per- 

 centage of oil, it will be seen that there is less than 5 per cent of a 

 perfect correlation between the oil and protein. 



Attention is called to the fact that in selecting seed corn by chemi- 

 cal analysis for high protein, there is a tendency to increase, not only 

 the horny starchy part (which contains more of the total protein than 

 any other part of the corn kernel), but also to increase the horny glut- 

 en and the germ, both of which, though small in amount, are rich 

 in protein, and consequently there is a tendency- for the oil to be in- 

 creased not only in the germ, but also in the horny gluten (aleuron 

 layer) which is quite rich in oil. This is the evident explanation as to 

 why there is a slightly higher degree of correlation between oil and 

 protein in our pedigreed strains of corn than there is in ordinary 

 corn which has not been so bred. 



Every low oil ear contains a small percentage of germ and every 

 high oil ear a high percentage of germ. Attention is called to the 

 fact that the high oil germ is even richer in oil than would be indicated 

 by the high germ percentage as compared with the per cent of oil 

 and germ in low oil corn, indicating that the breeding for high oil 

 has not only increased the oil by increasing the percentage of germ 

 (which contains most of the oil), but that there is also an increase in 

 the percentage of oil in the horny glutenous part. Similarly, the per- 

 centage of oil in the kernel has decreased even more rapidly than the 



(IB) 



