COEN BREEDING 137 



breeding, the strain continuously selected for its high 

 percentage of oil contained 7.37 per cent of fat, or nearly 

 three times as much as the strain selected for a low per- 

 centage of oil. The increase in oil makes this high-oil 

 strain more valuable for the manufacturers who produce 

 from it corn oil, and also gives to the grain a higher feeding 

 value, but a tendency to produce softer, less desirable 

 pork. 



In ten years, the average percentage of protein in the grain 

 was raised from 10.92 per cent at the beginning, to 14.26 at the 

 end of the decade. The high-protein strain was then nearly 

 twice as rich in this constituent as was the strain continuously 

 selected for a low percentage of protein. The high percentage 

 of protein gives to corn a higher feeding value, of a kind specially 

 desirable when corn must be fed without being combined 

 with other foods richer than itself in protein. Apparently, this 

 strain was less able to resist drought, making a lower yield in a 

 dry year than did the low-protein strain. It is highly probable 

 that the high-protein strain more rapidly exhausts the soil. 



In breeding for a high percentage of protein, the breeder should 

 not be deceived if the percentage of this constituent sliould run 

 abnormally high in a very dry season, a result which Hopkins and 

 Smith found to be due to the failure of the grain, under these 

 conditions, to assimilate its usual quantity of starch. 



123. Other effects of breeding for composition. — The 

 strain continuously selected in Illinois for low protein 

 made larger ears and a larger yield of grain per acre than 

 the higher protein strain; likewise, the strain poor in fat 

 generally yielded more grain per acre than the strain rich 

 in fat, and had larger ears than any other strain whatso- 

 ever. Its grains were broader, due to the larger proportion 

 of starch, and consequently there was a smaller number 

 of rows of kernels than on the ears of other strains. 



