228 
Journal of Agricultural Research 
Vol. XXI, No. 4 
No flowers on the original Pima plant were bagged for self-pollination, 
for its valuable qualities were not appreciated until a progeny row was 
grown the following year. It was then realized that a new type had 
arisen which differed in many characters from the Yuma variety. The 
progeny was remarkably uniform in view of the fact that it was grown 
from open-pollinated seed. The immediate progeny of the first Pima 
plant was grown in 1911 adjacent to a planting of the older variety, but 
very little hybridization could have taken place, for as far as the record 
shows, all plants in the five progenies which were grown in 1912 from 
selections made in 1911 exhibited only the distinctive Pima characters. 
After 1912 the Pima progenies were isolated from other cottons, but 
controlled self-pollination was not practiced in the earlier breeding work 
with this variety. 1 
A single plant selection, No. 5, in the 1911 progeny of the original 
Pima plant was the parent of progeny No. 5 which was grown in 1912. 
From a single plant selection, No. 3, in this progeny has descended the 
strain, henceforth referred to as 5-3, of which approximately 250,000 
acres were grown in Arizona and California in 1920. 
COMPARISON OF THE PRESENT COMMERCIAL STOCK WITH THE IM¬ 
MEDIATE PROGENY OF THE PARENT PLANT 
A progeny of 32 plants was grown in 1919 from open-pollinated seed 
of the original Pima plant. 2 Plates 48 and 49 show the range of varia¬ 
tion in shape and surface of the boll, each plant of the progeny being 
represented, with the exception of No. 5 which was accidentally omitted. 3 
Plants 1 to 17 are represented in Plate 48 and plants 18 to 32 in Plate 49. 
Two of these plants showed characters outside the normal range of 
variation of the Pima variety as it now exists. The others appeared to 
be typical in all respects. One of the aberrant plants (PI. 48, L) had 
bolls which were conspicuously shorter, broader at the base and near 
the apex, and less pointed than in typical Pima, and which resembled 
the bolls of a first-generation hybrid of the Pima and Gila varieties. 
The other plant, No. 28 (PI. 49, K), had bolls that were atypical in being 
more slender and less well filled out, and in having a less conspicuous 
“shoulder” and a more deeply pitted surface—characters which dis¬ 
tinguish the Yuma from the Pima variety. 4 All of the 28 individuals of 
a progeny grown in 1920 from selfed seed of plant No. 28 produced bolls 
which resembled the Yuma type in greater or less degree. 
Plant No. 28 of 1919 resembled the Yuma variety also in the very small 
amount of fuzz on the seeds, having been, in fact, the smoothest-seeded 
1 Evidence has been obtained recently that in the Egyptian type of cotton most of the ovules are self- 
ertilized even when no precautions are taken to prevent cross-pollination. 
3 Although the seed was nearly 9 years old, the germination was excellent and the plants made a vigorous 
fgrowth. 
3 The measurements indicate that plant No. 5 had bolls which were typical in shape. 
< Typical bolls of the Yuma, Pima, and Gila varieties of Egyptian cotton are shown on PI. 24, fig. 
3 and 3, and PI. 25, fig. 3, in Kbarnby, Thomas H.. op. cit. 1914- 
