A PURE-LINE METHOD IN CORN BREEDING 



be found that Cross CXH will give 120 bushels per acre of high-protein 

 corn, that FXL produces a similar yield of low-protein corn that KXC 

 gives the highest oil-content accompanied by high yield, and so on. 

 Moreover, it seems not improbable that different combinations may be 

 found to give the best results in different localities and on different 

 types of soils. The exchange of pure-bred strains among the various 

 experiment stations would greatly increase the number of different 

 possible hybrid combinations and facilitate the finding of the best 

 combination for each locality and condition. 



(2) After having found the right pair of pure strains for the attain- 

 ment of any desired result in the way of yield and quality, the method 

 of producing seed-corn for the general crop is a very simple though 



c H 



PLOT I 



cue 



PLOT II 



H C H 



FIG. 3. 



ARRANGEMENT OF THE TWO ISOLATED PLOTS FOR THE PURE-LINE 

 (METHOD OF CORN BREEDING. 



somewhat costly process. Two isolated plots will be necessary, to 

 which I may conveniently refer as Plot I and Plot II. (See fig. 3.) In 

 Plot I will be grown year after year only that pure strain which investi- 

 gation has proved to be the best mother-strain for the attainment of 

 the desired end. Thus, if it has been found, as in the example already 

 cited, that Cross CXH gives the desired result, Plot I will be occupied 

 by Strain C. This will require no attention from the breeder's point 

 of view except that any exceptionally vigorous or aberrant individuals 

 should be eliminated, as such plants might be safely assumed to be the 

 result of foreign pollinations. In Plot II Strain C and Strain H are 

 to be planted in alternate rows, and all of Strain C is to be detasseled 

 at the appropriate time. All the grain gathered from the detasseled 

 rows will be seed-corn for the general field-crop, and that gathered 

 from the tasseled rows will be pure-bred Strain H to be used again the 



