SEED SELECTION OP EGYPTIAN COTTON. 7 



The Yuma variety, which is now being grown in the Salt River- 

 Valley, originated in the course of plant-breeding work by the United 

 States Department of Agriculture. It appeared suddenly among 

 selections of the Mit Afifi variety, but is totally distinct from that 

 variety in all of its characters and has shown from the first a strong 

 tendency to produce uniform progeny. It is therefore to be regarded 

 as a mutation. 



Only one variety of cotton should be grown in a community. 

 Otherwise, there is sure to be crossing of the plants in the fields and 

 mixing of the seed at the gins. The result will be lack of uniformity 

 in the fiber produced and it will be found impossible to obtain the 

 high prices which manufacturers of fine cottons are willing to pay 

 for a uniform product. 



All cotton varieties, even when grown from carefully selected seed 

 and planted where crossing with other varieties is impossible, pro- 

 duce a certain number of off-type and inferior plants, which can be 

 recognized by the characters of their branches, leaves, and bracts. 

 Such plants should be carefully rogued out in order to obtain pure 

 seed for planting and thus maintain the uniformity of the stock. 

 Roguing should be done before the blossoms appear, in order to 

 prevent the crossing of the inferior plants with the good ones. 



The grower should select each year a few of the best plants in his 

 field, saving the seed from them separately and planting it in a spe- 

 cial plat for increase. Farmers who systematically follow this plan 

 will soon gain a reputation for the production of superior cotton. 



The associations of cotton growers in the Salt River Valley should 

 arrange each season with some of the best farmers who have uniform 

 land to have their fields rogued, in order that a supply of pure seed 

 shall be available for next year's planting. Great care should be 

 taken to have this superior seed ginned and stored under such con- 

 ditions as to prevent its getting mixed with other seed. 



LITERATURE WHICH MAY BE CONSULTED. 



Kearney, T. H., and Peterson, W. A. Egyptian cotton in the Southwestern 

 United States. U. S. Department of Agriculture, Bureau of Plant Industry, 

 Bulletin 128, 1908. 



Gives an account of the crop in Egypt, of the special uses of this type of cotton, 

 ■ and of the beginning of the plant-breeding work in the United States. 



Kearney, T. H., and Peterson, W. A. Experiments with Egyptian cotton in 

 1908. U. S. Department of Agriculture, Bureau of Plant Industry, Circular 

 29, 1909. 



A report of progress in the plant-breeding work. 

 Cook, O. P., McLachlan, A., and Meade, R. M. A study of diversity in Egyp- 

 tian cotton. U. S. Department of Agriculture, Bureau of Plant Industry, 

 Bulletin 156. 1909. 



Describes the different kinds of abnormal plants occurring in fields of Egyptian 

 cotton which became mixed through crossing with other types. 



