COTTON BREEDING 63 



72. Reasons for hybridizing cotton. One of the im- 

 portant objects in crossing different varieties or species 

 of cotton is to increase the variation in different directions 

 and thereby afford opportunity for greater selection than 

 would otherwise be possible. Also it is often possible 

 to unite in the hybrid desirable characters that are exhib- 

 ited by different individuals, varieties, or species. 



73. The nature of hybrids. When plants of different 

 varieties of cotton are crossed, the hybrid usually comes 

 nearly intermediate between the two parents in the first 

 generation. While it is true that these first-generation 

 hybrids are nearly uniform in the characters presented, 

 they are nevertheless very unstable individuals as is evi- 

 denced by the general breaking up of the characters in the 

 second generation, with the production of a large number 

 of variations. It is in this second generation that the de- 

 sirable variations are looked for. 



It has been found that the first generation of hybrids^ 

 in cotton are almost always more vigorous than either 

 parent. Especially is this true following the crossing of 

 different species of cotton such as the upland and Sea 

 Island. In succeeding years this increased vigor is grad- 

 ually lost as the hybrid becomes fixed in type, on account 

 of selection. 



74. Fixation of cotton hybrids. As above stated, 

 it is in the second generation of hybrids that all manner 

 of types are formed, the separate individuals exhibiting 

 the characters of the two parents in very different degrees. 

 The breeder should carefully examine the individuals of 

 this generation and select those which show, as nearly 

 as possible, the combination of characters which it is de- 

 sired to produce. These hybrids should be self-fertilized 

 the next year or, in other words, each plant should be pro- 



