SEED SELECTION OF 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. F., 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. 
