COTTON SELECTION ON THE FARM. 7 



lected field might be said to represent a different variety, for it is 

 generally possible by selection to establish a variety on the basis of 

 the peculiarities of any individual plant. Selection is to be thought 

 of as a process of narrowing the lines of descent, and thus securing a 

 greater resemblance among the progeny. A seed produced by self- 

 fertilization may be said to have only one parent, much as with plants 

 propagated from cuttings. 



Even the first generation of the progeny of a selected cotton plant 

 may show a notable resemblance to the parent, for a large proportion 

 of the seeds of the cotton plant usually represent the results of self- 

 fertilization by the pollen of the same plant. Some of the plants must 

 have descended from several generations of self-fertilized ancestors, 

 and are thus in the same condition of breeding as though they had 

 received the most careful selection. If the progeny are not uniform 

 at first, they are likely to become so in a few generations of careful 

 breeding. The growing of the offspring of single plants by themselves 

 also keeps them from being cross-fertilized by pollen from other cotton. 



If selection proves successful the result is to establish the expression 

 of the characters of the original selected plant in all of its progeny, so 

 that all the individuals of the stock shall show only the one set of 

 characters instead of the characters of the whole miscellaneous group 

 from which the original plant was selected. 



DETERIORATION OF VARIETIES WITHOUT CROSSING. 



The general result that is secured through selection is to keep the 

 characters of the inferior ancestors from coming into expression, but 

 selection does not seem to have any power to completely destroy the 

 characters of the inferior ancestors so as to prevent their continued 

 transmission for any number of generations and their subsequent 

 reappearance in individual variations. The work of the breeder is 

 never completely finished or absolutely successful. Though very 

 high degrees of uniformity are attained by careful breeders, such uni- 

 formity is not a permanent condition. It has always to be preserved 

 by further selection. 



Even in the most carefully selected varieties of our domesticated 

 plants and animals, where no crossing with other lines of descent has 

 been allowed for many generations, individual variations away from 

 the type continue to appear. With cotton grown under orchnary 

 field conditions it is generally impossible to determine whether any 

 particular variation has resulted from a crossing of varieties or from 

 a spontaneous mutative variation without any recent crossing. 

 Cotton pollen is carried by bees, and bees have been known to forage 

 for honey at least two miles from their nests. But for practical pur- 

 poses it makes little or no difference whether an inferior variation 



[Cir.,66] 



