COMMUNITY PRODUCTION OF EGYPTIAN COTTON. 13 



from a stock of Mit Afifi, the Yuma cotton is very distinct from that 

 variety in the characters of the plants and of the fiber. The lint 

 averages H inches in length (ranging, under different cultural and 

 soil conditions, from about l T 7 o to about 1-& inches) and has the 

 pale pinkish buff color of the Jannovitch rather than the deeper buff 

 color of the Mit Afifi. The lint percentage averages about 28. 



Yield tests and spinning tests of the Yuma cotton carried on 

 during several years demonstrated that a stable variety, uniform in 

 its characters and producing fiber of good spinning quality, had at 

 last been obtained. Seed was therefore placed in the hands of 

 farmers in the Salt Eiver and Imperial Valleys in 1912, with the 

 results described on preceding pages. 



From the Yuma variety there has originated another very distinct 

 new type, which has received the name " Pima " and which surpasses 

 the parent variety in productiveness, size of the bolls, and length and 

 quality of the fiber. Yield tests of the new variety and spinning 

 tests of its fiber are now in progress, and if the results bear out the 

 early promise it may be advisable to substitute this variety for the 

 one which is now grown commercially. 



MAINTAINING THE PURITY OF THE VARIETY. 



The immediate progeny of the individual plant from which the 

 Yuma variety originated was remarkably uniform, except that about 

 8 per cent of the plants were evidently first-generation hybrids. The 

 presence of these hybrids could readily be explained by the fact that 

 some of the flowers on the parent plant had been fecundated with 

 pollen from surrounding Egyptian cotton plants containing more or 

 less Hindi blood and from Upland cotton plants grown near by. 

 Seeds from the apparently nonhybrid plants in this progeny were, 

 used to plant a 4-acre field of the Yuma variety in 1909. Although 

 these plants had shown only the characters typical of the new Yuma 

 variety, about 2.5 per cent of their progeny of 1909 exhibited, more 

 or less distinctly, Hindi or Upland characters. All such plants were 

 rogued out of the field early in the summer, at about the time blos- 

 soming commenced. 1 



The vegetative characters of the Yuma variety are distinctive and 

 the recognition of hybrids is comparatively easy. It is therefore prac- 

 ticable to remove most of the " off-type" plants at a sufficiently early 

 stage of their development to prevent their crossing with the typical 

 plants. Careful roguing of the seed-increase fields jea,r after year 



1 The importance of the early roguing of cotton fields intended to furnish seed for 

 planting and the feasibility of recognizing the " off-type " plants in the early stages of 

 growth have been pointed out by Mr. O. F. Cook. (Cotton selection on the farm by the 

 characters of the stalks, leaves, and bolls. U. S. Dept. Agr., Bur. Plant Indus. Circ. 66, 

 23 p. 1910.) 



