July 15, 1914 
Mutation in Egyptian Cotton 
293 
degree of uniformity in its very distinct botanical characters. The prin¬ 
cipal characters by which it differs from the parent Yuma variety are 
enumerated in Table I, p. 291. The Pima variety bears a marked resem¬ 
blance to the discarded Somerton variety in the shape of the leaves, 
involucres, and bolls, but is almost the antithesis of that variety in its 
branching habit and seed characters. The Somerton showed an extreme 
development of the vegetative branches (much more so even than the 
Yuma) and had nearly smooth seeds, while the seeds of the Pima variety 
are very fuzzy for an Egyptian type. 
HISTORY OF THE PIMA COTTON 
In 1909 several selections, made in the original progeny row (No. 382) 
of the Yuma variety, were grown as progeny rows at Sacaton, Ariz., and 
of these No. 382-10, which was thoroughly typical of the variety, proved 
to be the best. Several acres were planted in 1910 with bulk seed from 
this row, 1 and numerous individual selections were made in this field. Of 
these, plant No. 382-10-0-14 was the progenitor of the Pima variety. 
This plant attracted particular attention because of its large and very 
sharp-pointed bolls. An excellent progeny row was grown in 1911 from 
the seed of this individual, and five individual selections were made in 
this row. These selections were characterized by the marked reduction 
of the vegetative branches and by the retention of fruiting branches excep¬ 
tionally low on the main stem. The selection which produced the best 
progeny the year following (plant No. 382-10-0-14-5) was noted as hav¬ 
ing the first fruiting branch low on the main stem (at node 10), the limbs 
much reduced, and the bracts nearly distinct. 
The five progeny rows grown from these selections at Sacaton in 1912, 
when observed in July, greatly resembled each other and presented a very 
distinct and uniform type. They were in strong contrast to all other 
groups of progenies in the breeding nursery by reason of the marked 
reduction of the vegetative branches, which were generally fewer and were 
uniformly much shorter than in the Yuma variety. In one of the rows 
the reduction amounted to practical suppression. Correlated with this 
there was a strong tendency to retain the fruiting branches at a lower node 
of the main stem and to retain more bolls on the lower fruiting branches 
than is usual in the Yuma variety. 
Row No. 382-10-0-14-5 proved more uniformly productive and long 
fibered than the other four, although the development of the vegetative 
branches was somewhat greater than in one of the other rows. 2 3 Twenty 
individual selections were made in this row and a smaller number in thre e 
of the other progeny rows of this type. Fourteen of the selections in r ow 
1 This field was carefully rogued, and the resulting seed was planted for increase in 1911. This was the 
source of the seed used in commercial plantings in 1912, 1913, and 1914. Hence, the Yuma variety as now 
grown by fanners in the Salt River Valley is derived from Selection No. 382-10. 
3 The 1913 progenies from selections in row No. 382-10-0-14-5 showed, however, less development of limbs 
than did the progenies from the other rows. 
