276 MAINE AGRICUI^TURAI, EXPERIMENT STATION. I91O. 



mens belonging to mediocre genotypes, whereas the ears in Fig. 

 226 represent very good individual specimens but also from 

 mediocre genotypes. If both sets belong to genotypes of about 

 the same general grade or character it is to be expected that the 

 progeny of both sets of ears will be essentially the same. This 

 as a matter of fact was the case. The genotype concept gives 

 at once a more reasonable interpretation of the facts than is to 

 be gained from any other current view of the nature of the 

 process of inheritance, and suggests the factors of primary im- 

 portance to be looked after in practical corn breeding. Evident- 

 ly if the genotype idea represents the actual method of inheri- 

 tance in corn, the important test in selecting seed is the perform- 

 ance of the progeny. The aim must be to propagate the strains 

 or lines in which high yield, fine quality of ears, etc., are heredi- 

 tarily present. At the same time one must, of course, guard 

 against any loss of vigor by too much or too close inbreeding.* 

 It is obvious that in an open fertilized plant like corn one will 

 never (except by hand pollination) get pure lines such as 

 Johannsen has studied in beans. But to suppose, as some 

 writers have apparently done that, because of this fact, the geno- 

 type concept has no significance for sexually reproducing ani- 

 mals and open fertilized plants, is merely a confession of a lack 

 of understanding of the fundamental meaning of that concept. 



Work in 1909 — I. Ear-to-Row Test. 

 The ear-to-row test of the ears from individual plant selection 

 was carried out on the farm of Mr. J. H. Heath at Farmington- 

 again in 1909. Land was taken for the work on the "intervale" 

 contiguous to that used in Plot I in 1908. The soil was of the 

 same character. In addition to the ear-to-row test a number of 

 other test plots were carried on in 1909. Besides the experi- 

 mental plots Mr. Heath grew two acres of corn for himself 

 from seed selected for him by the writers. This corn was on 

 the same "intervale" land immediately west of the experimental 

 plots This gave nearly 3 acres of the Type I pedigreed sweet 

 corn grown in the same field at Farmington under direct obser- 

 vation, and in the local conditions to which it was thoroughly 

 adjusted. 



* This point has been much discussed in recent writings on corn 

 breeding problems, especially by Shull, East, Cook, Spillman, and Collins. 



