BREEDING AND SELECTION; 



67 



and cut out or detassel all poor or dwarf stalks which 

 later might prove to be barren stalks. This should 

 be done just as the tassels are coining out, and before 

 any of the pollen has been shed. This plan will pre- 

 vent the seed being fertilized by the pollen of these 

 undesirable stalks. 



Corn is Cross-Pollinated — Corn is cross-fertilized. 

 The silks on a stalk generally mature at a different 



IP 





^Tr.t^" 



. 



Fig 20— Effect of Four Years' Inbreeding 



Small row inbred; large row cross-bred 



time than the pollen and thus the pollen of one stalk 

 fertilizes the silks of other stalks. Careful estimates 

 show that a well-developed tassel may produce as 

 many as thirty to sixty million pollen grains. These 

 pollen grains are wafted by the wind about the field, 

 and if blown upon silks which are ready for fertiliza- 

 tion they will attach themselves to them and perform 

 the function of fertilization. This production of 

 pollen is an enormous draft on the strength of the 



