# ILLINOIS DAIRYMEN'S ASSOCIATION. 227 



As more than 85 per cent of the oil in the kernel is contained in the 

 germ, it follows that ears of corn are relatively high or low in their oil 

 content, according as their kernels have a larger or smaller proportion of 

 germ. 



In selecting seed corn by mechanical examination for improvement 

 in composition we remove from the ear a few average kernels; cut two 

 or three of these kernels into cross sections and two or three other kernels 

 into longitudinal sections and examine these sections as they are cut, 

 usually simply with the naked eye. 



If we are selecting seed ears for high protein content we save those 

 ears whose kernels show a small proportion of the white starch imme- 

 diately adjoining or surrounding the germ. If selecting corn for low pro- 

 tein content we look for a larger proportion of white starch surrounding 

 the germ. Our results have shown that the white starch in this position, 

 that is, surrounding the germ toward the tip end of the kernel, is a better 

 index of the protein content than the starch in the crown end. 



If we are selecting seed ears for high oil content we save those ears 

 whose kernels show a large proportion of firm and solid germ; while if 

 seed of low oil content is desired, we look for a small proportion of germ 

 in the kernel. 



It should be emphasized that it is not the absolute, but proportionate, 

 siae or quantity of germ or of white starch which serves as a guide in 

 making these selections. 



Chemical Selection by Chemical Analysis. 



* In selecting seed corn by chemical analysis we remove from the indi- 

 vidual ear two adjacent rows of kernels as a representative sample. This 

 •ample is ground and analyzed as completely as may be necessary to en- 

 able us to decide whether the ear is suitable for seed for the particular 

 kind of corn which it is desired to breed. Dry matter is always deter- 

 mined in order to reduce all other determination to the strictlyu niform and 

 comparable water-free basis. If, for example, we desire to change only 

 the protein content, then protein is determined. If we are breeding to 

 change both protein and the oil, then determinations of both of these 

 constituents must be made. 



