B. P. 1.-593. 



THE VALUE OF FIRST- GENERATION 

 HYBRIDS IN CORN. 



INTRODUCTION. 



The use of first-generation liybrids oflfers one of the most promising 

 methods of increasing the yield of corn. The evidence that crossing 

 can in general be relied upon to give an immediate increase of vigor 

 and productiveness appears conclusive, yet the practice seems never 

 to have been applied on a commercial scale. The plan of utilizing 

 first-generation hybrids involves the making of the cross anew each 

 year, and this is readily feasible with corn. Many efforts have been 

 made to develop hybrid varieties, but the increased vigor and pro- 

 ductiveness that result from hybridization appear to be confined 

 largely to the first generation and to disappear gradually in later 

 generations. 



The present paper reports experiments with a series of first- 

 generation hybrids between widely different types of corn and brings 

 together the results of previous experiments. Investigations that 

 warrant the placing of confidence in this method of increasing the 

 yields of corn are scattered over a long period of years, and most of 

 them appear to have been made in ignorance of similar work pre- 

 viously reported. Individual experiments taken alone have not 

 made it perfectly clear that the results were not accidental, but the 

 assembled evidence forces the conclusion that the increases secured 

 in the first generation by crossing varieties can be made a factor of 

 production comparable in importance to breeding. 



It was indicated more than three decades ago that seed pro- 

 duced by crossing two varieties of corn could be relied upon to pro- 

 duce larger crops than the parents, and that this increase was to a 

 great extent lost in following generations. 



At about the tune when it was discovered that an increase in yield 

 and vigor followed the crossing of two varieties, the attention of 

 investigators was attracted to the possibility of the improvement of 

 corn through what then appeared the more scientific methods of 

 selection. The latter idea was in accord with the most advanced 

 ideas of evolution, while the former appeared as an isolated fact dis- 

 covered by accident. 



52927°— Bull. 191—10 2 7 



