42 



THE BOOK OF WHEAT 



limited to the few very best wheats, for a fairly large number 

 of varieties can be used profitably for special characteristics. 

 The great advantage of hybridization is shown in three ef- 

 fects, all of which aid in accomplishing more rapidly the 

 results aimed at in selection. It makes it possible immediately 

 and directly to combine the qualities of two different plants 

 in one; it immensely increases that variation which alone 

 makes selection possible ; and it imparts greater vigor to the 

 offspring. Hybridizing does not always give a progeny im- 



Hybrid* 



Hybrid 7 



DIAGRAM SHOWING PEDIGREE OF GARTON^S HYBRID. 



mediately averaging better than the parents. In many cases 

 the first progeny will average much poorer than either parent. 

 Its great value lies in throwing together qualities and multi- 

 plying variations, both of which may be developed by selec- 

 tion. This greatly increased variation has been explained on 

 the ground that "the wheat plant being so closely self -fertile, 

 there is within it, lying dormant, a wonderful power to vary 

 (a power far greater than in plants cross-fertilized in nature), 

 which is thrown into action when different varieties are arti- 

 ficially crossed. " As to these varieties Hays says: "The 

 further they have departed from ancestral characteristics and 

 formed diverse qualities, the more likely will their progeny ex- 

 hibit new characteristics made up by combining those which 

 have become so radically different in the two parents. " ' There 



1 Carleton, Basis for Tmprov. of Amer. Wheats, p. 73. 

 a Plant Breeding, p. 37. 



