76 



of some other species. It is important, therefore, that all hybrids 

 intended for a particular district should either be produced in that dis- 

 trict or transferred there before they have become fixed, in order that 

 the careful selection necessary may be continued in accordance with 

 the tendencies developed under the influence of the new conditions. 



Ward's White 



^Gypsunh C 



Jiomblenae 



^edeah 



Hybrid 1 



Huhrid 2 



KTjbrid4 



Improved Fife 



SyhridJ 



Fig. 4.— Diagram showing pedigree of one of Farrer's hybrid wheats. 



Another matter of importance should be noted before leaving this 

 topic. It was supposed for a time, and is still supposed by some, that 

 varieties from different wheat groups will not cross with each other. 

 Often this is true if it is attempted to cross them directly; but it shows 

 another great advantage of composite crossing that if these same varie- 

 ties are first crossed with others of the same group, or with those of 

 groups more nearly allied, the resulting progeny will cross more 

 readily with that of a widely different group. For example, instead of 

 attempting to cross a common wheat with a spelt, the desired result 



Common Common 



Club 



Spelt 



Spelt 



Hiihrid 2 



HvhricL 



Svhrid ^ 



Fig. 5.— Diagram showing hypothetical cross of wheat and spelt. 



would be more certainly and easily attained 1>y means of a composite 

 cros.s .similar to that shown in the accompanying diagram (fig. 5), and 

 at the same time there is a much better chance offered for selection 

 because of the increased amount of variation thereby induced. 



