44 PLANT BREEDING. 



mere inspection and without chemical analyses, though chemical 

 analysis is a great aid. Those kernels which showed the largest pro- 

 portion of dark reddish to white starchj^ interior, when cut across, as 

 with a knife, had the highest percentage of nitrogen, thus enabling 

 the careful farmer to select for more nitrogen. 



ILLUSTRATIONS OF WORK IN PLANT BREEDING. 



No attempt can be made here to go into the minute details of breed- 

 ing the many species of economic plants. The discussion of wheat, 

 corn, timothy, potatoes, apples, black walnuts, and flax in future pages 

 serves .to illustrate many of the general methods. Those who Avish to 

 engage in the breeding of any plant should first study that plant, pay- 

 ing special attention to its floral organs and to its method of pollina- 

 tion, to the methods of propagating and cultivating it, to the conditions 

 under which it is to be grown, and to the purposes for Avhich it is or 

 might be used. 



The literature will not be found extensive nor explicit in most lines, 

 but by applying to his State experiment station, to the national Depart- 

 ment of Agriculture, and to persons who have bred the plant concern- 

 ing which knowledge is desired, the plant breeder can secure valuable 

 information. The discussion which follows, besides showing present 

 plans and results, is meant to be suggestive in relation to plans 

 for breeding many other crops for which the experimenter must 

 develop methods. 



BREEDING WHEAT. 



The breeding of wheat should not be confined to the few very best 

 wheats, but a fairly large number of varieties maybe profitably used, 

 especially in forming new varieties by hybridizing. The best of these, 

 if not all, should be placed under systematic field tests to determine 

 their relative value, and to establish standai-ds with which to com- 

 pare newly originated varieties. 



IMPROVEMENT BY SELECTION ALONE. 



In nearly all cases wheat flowers are fertilized with their own 

 pollen, and, in order that the occasional plants which have hereditary 

 power of special value may be secured, it is necessary to plant large 

 numbers of seeds in such a manner that each plant will have an 

 opportunity equal to that given each other plant. At the Minnesota 

 experiment station this is accomplished in the following manner: 

 Twenty-five hundred good kernels of spring wheat are chosen from 

 the bulk wheat of a good variety, either old or newly formed. These 

 seeds are planted in hills 4 inclies apart each way (5 inches for winter 

 wheat), one seed in a hill. A dibble may be used to make the holes 

 for the seeds, and the grains may be inserted and covered by hand. 

 To get the hills tlie proper distance apart each way a large frame is 

 used (see PI. II, fig. 2). The long boards at the sides of the plot, or 



