CHAPTER IX 



METHODS OF LAYING OUT A BREEDING- 

 PLAT 



While the principle underlying systematic selection is 

 simple, it has been more difficult to develop good methods 

 for carrying out the selection work in order to avoid error. 

 Breeding-plot methods have had a steady development, 

 each step in advance being intended to overcome some 

 source of error or to develop some new possibilities. 



In the reference on " Methods of pedigree selection," 

 given on a previous page, several methods for conduct- 

 ing a breeding-plat are given. The development of the 

 breeding-plat plan may be summarized in the following 

 brief way, beginning about 1895 ; — 



68. 1. Select a number of mother ears and plant in 

 parallel rows, taking the yield of each row and saving 

 seed ears from this row to continue in the same manner. 

 (See 111. Agr. Exp. Sta., Bui. 55.) 



2. The above plan was found to favor inbreeding and 

 close breeding, with danger of decreasing yield. In order 

 to avoid this it was recommended to detassel every odd 

 row, sowing seed from only the detasseled rows. Thus, 

 every odd row became a dam while the even rows would 

 be the sires. By duplicating the plat and detasseling 

 the even rows in the duplicate, seed could be saved from 

 every mother ear. (111. Agr. Exp. Sta., Bulls. 82 and 100.) 



94 



