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 1J inches in length (ranging, under different cultural and 
soil conditions, from about 1^ to about 1 T \ 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 River 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 year after year 
!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.) 
