'40 THE BOOK OF WHEAT 



also resulted in adapting corn to regions far north of its 

 former habitat. Wheat perhaps has not been so generally im- 

 proved by selection as corn has, but the wide practice of seed 

 grading through the use of the fanning mill must have similar 

 results. This '"is a slow process, however, and no great changes 



iare effected at any one time. 



Natural selection is also continually operative, especially in 



; connection with such qualities as rust resistance and hardiness 

 against heat, drought or cold. Thus wheat naturally tends to 

 adapt itself to its environment. Such crude methods of seed 

 selection as have been practiced in conjunction with natural 

 selection have been the factors in evolving Turkey wheat so 

 that it is more drought resistant than formerly, and has im- 

 proved in hardiness so that it can be grown much farther 

 north. Quality of the grain in any respect, yield, earliness in 

 ripening, and non-shattering, in addition to the qualities just 

 named above, are some of the most important characteristics 

 that may be readily increased on any farm by selecting seed 

 from those plants which exhibit these qualities in the highest 

 degree. As these things cannot be properly determined after 

 harvest, all selections for seed should be made in the field. 

 Marked variations or sports possessing improved characters are 

 occasionally met with in the fields. These are often carefully 

 developed into valuable races by seed selection. Fultz, some 

 of the Fife wheats, and many other well-known races have 

 been originated in this way. 



Hybridization consists in cross-fertilization. This may be 

 simple, the fertilization of one race with another, resulting in 

 a hybrid of two bloods, or it may be composite, the fertilization 

 of a hybrid with another race or hybrid, resulting in a hybrid 

 containing the blood of three or more races or species. Hy- 

 bridization may be natural or artificial. Natural hybrids rare- 

 ly occur. This is shown by growing different varieties of 

 wheat side by side. Why varieties do not cross under these 

 circumstances has not been fully explained. It is claimed that 

 over half of the pollen from an anther is deposited into the air, 

 and it would seem that it could readily find its way to adjacent 

 flowers. Possibly the stigma is usually not receptive to foreign 

 pollen. 



