92 MISSOURI AGRICULTURAL REPORT. 



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 

 protein content we look for a larger proportion of white starch sur- 

 rounding the germ. Otir 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 

 cars 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 proportion- 

 ate, size 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 in- 

 dividual ear two adjacent rows of kernels as a representative sample. 

 This sample is ground and analyzed as completely as may be necessary 

 to enable us to decide whether the ear is suitable for seed for the par- 

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

 determined in order to reduce all other determinations to the strictly uni- 

 form and comparable water-free basis. If, for example, we desire to 

 change only the protein content, then protein is determined. It we are 

 breeding to change both the protein and the oil, then determinations of 

 both of these constituents must be made. 



For a satisfactory breeding plot, about 20 to 40 selected seed ears 

 are required. If the breeder desires to make only physical improve- 

 ment then he should select, say, 40 of the most nearly perfect ears which 

 it is possible to pick out by inspection or by exact physical measurements. 

 H it is desired to improve the composition or (juality oi the corn as well 

 as the physical properties, then at least 200 physically perfect ears should 



