23O ILLINOIS DAIRYMEN'S ASSOCIATION. 



being taken from each ear, and one composite sample of the 20 to 40 

 selected seed ears, twenty average kernels being taken from each of these 

 ears, and each of these two composite samples being properly labeled 

 and analyzed. 



One of the best selections which has yet been made by mechanical 

 examination was accomplished last spring by a farmer who is breeding 

 corn for higher protein content. Out of a lot of 165 ears of corn he 

 selected 15 ears whose protein content averaged 1.48 per cent higher than 

 that of the 150 rejected ears, as was determined by the chemical analysis 

 of a composite sample from each of the two lots. Because of the chemical 

 control which the Station affords him, he knows each year just how much 

 he has accomplished. 



If the purpose of breeding a kind of corn is principally to change its 

 content of a single constituent, as to increase protein, then the selection 

 of the best 40 ears is simple and regular by either method; but if it is 

 desired to effect changes in the content of two constituents, as to increase 

 the protein and to increase the oil in the same corn, then one could hardly 

 expect to make much progress in both directions, if he relied solely upon 

 mechanical examination of kernels for chemical selection of seed ears. 

 Even after the chemical analyses of 100 ears have been made it requires 

 some computation to determine which are really the best 40 ears. For 

 example, an ear may be desirable for seed because of its high protein 

 content, but it may not be sufficiently high in oil. In order to reduct the 

 selection to an exact basis, we have adopted simple mathematical compu- 

 tations for all such cases. 



For high protein and high oil in the same corn, we multiply the per- 

 centage of protein by the percentage of oil and use the product as the 

 selection coefficient, the forty highest products designating the forty best 

 ears. 



For low protein and low oil we multiply the percentages together 

 and use the lowest product as the selection coefficient. 



For high protein and low oil in the same corn, we divide the percen- 

 tage of protein by the percentage of oil and use the highest quotients as 

 our selection coefficients. 



