48 BULLETIN 1111, U. S. DEPARTMENT OF AGEICULTURE. 



tendency to mixing and degeneration of varieties. But this tendency 

 may be counteracted by organizing one-variety communities. 



Though larger units are desirable, the practical minimum of 

 organized production is the gin-unit community, to include all the 

 farmers who take their cotton to the same gin. Separate ginning 

 and isolation and roguing of seed fields is essential to organized 

 effort for utilizing superior varieties of cotton. The mixing of 

 different kinds of seed at the gins is the chief agency of deterioration 

 of varieties, and must be avoided if other precautions are to be of 

 practical value. 



Except for the deterioration that results from the mixing and the 

 crossing of different sorts there is no basis of fact for the popular 

 idea that varieties of cotton run out rapidly or need to be changed 

 frequently. With precautions of isolation, careful selection and 

 roguing of the seed fields, and separate ginning, a variety of cotton 

 can be kept pure and uniform and grown for many years. Produc- 

 tion should be stabilized by the continued use of standard varieties. 

 New sorts should not be substituted until their superiority is defi- 

 nitely shown and such seed supplies are available that whole com- 

 munities can change at one time. It is wasteful of good seed to send 

 it out to scattered individual farmers in mixed-variety communities 

 where isolation and separate ginning are not provided. 



Numerous varieties of cotton are unnecessary and undesirable both 

 for agricultural and for industrial reasons. The commercial prac- 

 tices of introducing many new kinds or of renaming old varieties to 

 meet popular demands are based on a misunderstanding of the facts 

 and do not tend to improve production, but add to the mixture of 

 the " gin-run " seed. 



Though many varieties of cotton have been bred and distributed 

 by the United States Department of Agriculture, only those are 

 being maintained and extended on a scale of commercial produc- 

 tion that have been adopted and centralized in communities so as 

 to provide larger supplies of pure seed. Experience of nearly two 

 decades has shown that the breeding and distribution of seed of 

 superior varieties, either by the United States Department of Agri- 

 culture or by local or private efforts, does not result in any general 

 improvement of production, because of the lack of any adequate 

 system for developing and maintaining large supplies of pure seed. 

 Studies of utilization and of seed-supply problems have shown no 

 way to develop and maintain adequate supplies of pure seed of 

 superior varieties and keep such seed supplies permanently available 

 except in one-variety communities where the mixing of seed at the 

 gins and the crossing of varieties in the fields are avoided. 



Experience of several years in one-variety communities estab- 

 lished in irrigated valleys of the Southwestern States has demon- 



