38 MISCELLANEOUS PAPERS. 
the numerous experiments of European settlers in tropical America, 
who are prone to regard as superstition this native belief and to 
import improved varieties from more or less distant localities. The 
failure is usually so complete the first year that the experiment is 
abandoned. This abnormal behavior of corn under new conditions 
intensifies the close breeding, and the close breeding in turn operates 
against the interchange of varieties by making the adjustments to 
the particular environment more delicate. That these primitive 
systems of breeding have not been indiscriminate is shown by the 
great number of well-defined types that exist among the American 
aborigines. 
Among a number of primitive tribes where the cultivation of corn 
has reached a high state of development, the injurious effect of this 
close breeding appears to have been recognized, since they have meth- 
ods of guarding against it. Thus the Indians in the region of Que- 
zaltenango, in western Guatemala, and the Hopi Indians of Arizona 
make a regular practice of placing seeds of more than one local 
variety in each hill, with the idea that larger yields can be obtained 
in this way. 
The very general fact that the immediate effect of crossing two 
closely bred strains is to increase the vigor is well exemplified in corn. 
Although this increased vigor of first-generation hybrids is well 
recognized by many practical corn breeders, the value of the fact has 
been largely obscured by the idea that the hybrid must be considered 
as a new variety and that uniformity must be secured before the 
results could have general application. To attempt to establish uni- 
formity by a new course of selective inbreeding is to sacrifice the 
vigor gained by crossing. 
Attention has been so persistently centered on the production of 
new and uniform strains that the yield and vigor of the first genera- 
tion of hybrid plants as compared with the parents is seldom reported. 
In all the cases that have come to our attention the yield of the 
hybrid has been in excess of the average of the parents. Five cases 
reported by Morrow and Gardner,’ of the Llnois Agricultural Ex- 
periment Station, gave increases over the average of the parents 
running from 1.9 per cent to 28 per cent, with an average increase of 
14 per cent. McClure,’ of the same station, also reports on 12 differ- 
ent hybrids of sweet, pop, soft, and flint varieties; 10 showed an 
increase in the weight of the ear in the first generation over the 
average of the parents, and one of the exceptions is explained by the 
author as being due to unfavorable situation, the decrease in the 
4 Morrow, G. E., and Gardner, F. D. Bulletin 25, Illinois Agricultural Exper- 
iment Station, p. 179. 1898. 
®’ McClure, G. W. Bulletin 21, Illinois Agricultural Experiment Station, p. 82. 
1892. 
141—1y 
