186 INTRODUCTION TO BOTANY 
not thoroughly carried out, much self-pollination and self- 
fertilization is sure to occur. Corn which is  self-fertilized 
produces smaller and less vigorous plants the next season 
than cross-fertilized corn (fig. 159). Detasselmg has there- 
fore been found to increase the yield of corn more than ten 
bushels per acre.! 
175. Williams’s method. The method of corn breeding as 
above outlined has been criticized on the ground that little or 
no attention is paid to the productiveness of the plant used 
as the source of pollen. A new system devised by Professor 
C. G. Williams, of the Ohio Agricultural Experiment Station, 
provides for equally careful selection of the staminate and 
pistillate parents. The system in its barest outlines, as stated 
by Professor Williams, provides for 
1. The usual ear-row test. Only a portion (usually about one half) 
of each ear is planted. The remnant is carefully saved, and when the 
ear-row test has shown which ears are superior, recourse is had to the 
remnants to perpetuate these ears in a later season. 
2. An isolated breeding plot in which are planted the four or five 
best ears as demonstrated by 1. Not the progeny of the best ears, but 
the vriyinal ears. Usually the best ear is used for staminate plants and 
planted on each alternate row in the small breeding plot. All the plants 
from the other ears going into the plot are detasseled. 
The pedigreed strains produced in the breeding plot are multiplied 
for general field use and also furnish ears of varying worth for a second 
ear-row test, if it is desired to continue the improvement. 
The ear-row test need not be isolated, for no seed is taken from it. 
Neither is there any need for detasseling until the breeding plot is 
reached. 
176. Hybridizing. \s has already been shown (sects. 13 
and 127), seed production is the result of fertilization of the 
egg within an ovule by a pollen grain. Usually the pollen 
and the ovule concerned in fertilization are derived from 
plants of the same species. Often pollen of another species is 
' For details about corn breeding see De Vries, Plant Breeding, The Open 
Court Publishing Company, Chicago; Bulletin 700, Minois Agricultural Ex- 
periment Station ; and Circulur 66, Ohiv Agricultural Experiment Station, 
