36 ILLINOIS ACADEMY OF SCIENCE. 



method of continuous selection and building up inconstant forms 

 seems no longer necessary, for the desirable forms already exist, 

 and are constant; and they do not need to be built up, but only 

 discovered and propagated. There is no doubt as to the enormous 

 success of Nilsson with the oats and barley of Sweden ; but it 

 is too early to predict the applicability of this beautifully simple 

 method to all other crops. 



No citizen of the United States, and especially of Illinois, could 

 fail to raise the question of corn-breeding, perhaps the most 

 difficult of all plant-breeding operations. Does pedigree culture 

 apply here, and if so, has it achieved any important results? 

 The answers to these questions are well-known to plant breeders, 

 but perhaps it may not be inappropriate, in a meeting of the 

 Illinois Academy, to call attention to the extremely important 

 work that has been done in this state in connection with our 

 greatest crop. It was one of our own colleagues. Professor 

 Hopkins, who nearly fifteen years ago proved the individuality 

 of ears of corn, both in physical features and in chemical compo- 

 sition. That is, all the kernels of an ear have the same character- 

 istics provided, of course, cross-pollination has been excluded, and 

 these characteristics are constant. This is certainly individual 

 selection in the strictest sense. Moreover, the range of selection 

 is remarkably wide, for corn is an exceedingly variable plant, 

 probably much more so than are the other cereals. This breeding 

 of corn on the principle of single ear selection, through the wise 

 organization of interest by Hopkins, has resulted in a great 

 increase in the total yield of the state. It ought to be recognized, 

 however, that while selection is made easier than in other cereals, 

 on account of the great number of kernels upon a single ear, 

 it is more difficult to obtain the desired result because of the 

 open and prolonged pollination. With freely exposed "silk," 

 widely carried pollen, and a pollinating period of four or five 

 days for a single ear, it is to be expected that some of the kernels 

 will be hybrids, and these hybrids usually cannot be recognized 

 unless contrasting colors are involved. This means more or less 

 continuous selection in subsequent generations to eliminate the 

 hybrids. It is an interesting obstacle to work against, to know 

 definitely the pedigree on the female side, and to know only 

 vaguely the pedigree on the male side. 



Still more recent work in the breeding of corn has developed 

 some new situations. The fact has been emphasized that a field 



