1907.] PLANT BREEDING PRINCIPLES AND RESULTS. II5 



Some of our own most important agricultural crops, such as 

 corn, tobacco, and potatoes are natives of America, and the 

 beginnings of their improvement by the white race therefore 

 date from the sixteenth century. In some places in America, 

 however, the Indians had already developed comparatively 

 systematic methods of agriculture, and it may be that the 

 value of their work is underestimated. It is stated that several 

 varieties of corn, including one of sweet corn, had been origi- 

 nated by the Indians of what are now the New England States, 

 and that when the settlers of Massachusetts obtained seed from 

 them, they taught them methods of selecting the largest and 

 finest ears for their next spring's planting. It is here that we 

 have the genesis of corn breeding. We might even go further 

 and say that here advancement in corn breeding stopped until 

 the introduction of the ear-to-the-row breeding plot, only a few 

 years ago. It is true that several general laws had been estab- 

 lished some time before, but they have only lately come into 

 general practical use. 



The first of these laws upon which we base modern plant 

 breeding was the discovery of the sexuality of plants by 

 Camerarius in 1691. This, however, was not put to any prac- 

 tical use until 1719, when Thomas Fairchild, an English gar- 

 dener, crossed the carnation with the sweet william. From this 

 time there is a gap in the progress of the work until the begin- 

 ning of the nineteenth century, when Thomas Andrew Knight, 

 an eminent English plant physiologist, showed the practical 

 value of crossing and hybridizing in the production of plant 

 varieties. Another important principle emphasized by Knight 

 was that of inducing variation in plants by an increase or de- 

 crease of the food supply. At almost the same time a Belgian 

 horticulturist, Van Mons, published several papers of almost 

 equal importance in which he emphasized the principle of 

 selection. Finall)*, came the introduction of a practical method 

 to test the average productive efficiency of individual plants 

 in particular characters, as illustrated by the ear-to-the-row 

 comparison of the productiveness of ears of corn in the mod- 

 ern breeding plot. And while the literature on plant breeding 

 of late years has been large, and the new principles involved 

 of striking importance, we can hardly say that our present 

 methods are any more than variations of these three basic 

 principles : namely, inducing variation by means of crossing 



