16 GEORGE HARRISON SHULL 



the first to make extensive use of controlled cross-pollination in the breed- 

 ing of corn. Beal was a student of Asa Gray from 1862 to 1865, when the 

 latter was in active correspondence with Charles Darwin. Darwin was be- 

 ginning the studies on cross- and self-fertilization, which were reported in 

 1877 in an important book on the subject. It has been thought that Darwin's 

 views on the significance of crossbreeding may have been instrumental in 

 inciting and guiding Beal's experiments in the crossing of corn. There seems 

 to be no supporting evidence, however, for such a surmise. 



Beal's lectures before various farmers' institutes stressed the importance 

 of being able to control the source of the pollen, so that the choice of good 

 ears in the breeding program would not be nullified by pollen from barren 

 stalks and other plants of inferior yielding capacity. On this point Professor 

 Perry Greeley Holden, for several years assistant to Dr. Beal, has stated that 

 controlled parentage, not heterosis, was the aim of the corn breeding pro- 

 gram at Michigan and at Illinois before 1900. 



In 1895 Holden was invited by Eugene Davenport to become professor of 



agricultural physics at the University of Illinois. Davenport also had served 



for several years as assistant to Dr. Beal at Michigan. Like Holden, he was 



very enthusiastic about the importance of Beal's program, so it was natural 



that Davenport and Holden should agree that corn improvement be a major 



undertaking of Holden's new department at the University of Illinois. On 



initiating this work at the University of Illinois, they learned that Morrow 



and Gardner already had tested Beal's variety crossing at Illinois before they 



got there, and with confirmatory results. Concerning the motivation of all 



this early work, both at Michigan and at Illinois, Holden says: 



1. Hybrid corn [as we know it today] was unknown, not even dreamed of, previous to 

 1900. 2. Controlled parentage was the dominant purpose or object of this early corn improve- 

 ment work. 



Holden thus makes it clear that while heterosis was at play in all of this early 

 work, it was not the result of, nor did it result in, a heterosis concept. 



I refer next to the matter of inbreeding, which some writers have confused 

 with the crossing that has brought the benefits of heterosis. Enough selfing 

 had been done with corn prior to 1900 to convince all of those who had had 

 experience with it that it resulted in notable deterioration. The results of these 

 early observations are aptly summed up by Holden in the statement that 

 "Inbreeding proved to be disastrous — the enemy of vigor and yield." No- 

 where, so far as I have been able to determine, did any of the early inbreed- 

 ers discover or conceive of the establishment of permanently viable pure lines 

 as even a secondary effect of inbreeding. 



In 1898 A. D. Shamel, then a Junior in the University of Illinois, offered 

 himself to Holden as a volunteer assistant without pay. He did so well that 

 when Holden severed his connection with the University in 1900, Shamel 

 was appointed his successor, and continued in this capacity until 1902. He 



