22 
BULLETIN 1365, U. S. DEPARTMENT OP AGRICULTURE 
sponding nodes on branches of the main stalks. From the variations 
exhibited by the percentages of shedding from the last node of long 
fruiting branches or of branches of only one node it is impossible to 
determine what the behavior of these nodes might be in regard to boll 
shedding. 
In relation to the features of boll shedding dealt with here, it may 
be pointed out that Zaitzev (21), working in Turkestan, found that 
boll shedding on upper branches was greater than on lower branches 
and also that the shedding was increased toward the ends of the 
branches on any part of the main stalk. 
Table 15. — Percentage of bolls shed from specific nodes of the fruiting branches 
on the main stalks and vegetative limbs of 20 plants each of Pima and Acala 
cotton in 1924 and 1925 
Season, variety, and parts 
Nodel 
Node 2 
Node 3 
Node 4 
Node 5 
Node 6 
Last 
node 
only 
Branches 
of one 
node only 
Season of 1924: 
Pima— 
Main stalks 
15.1 
74.9 
77.5 
5.6 
35.1 
55.1 
70.2 
13.1 
79.0 
87.2 
8.1 
44.9 
60.9 
76.3 
22.9 
82.6 
100 
17.3 
29.6 
91.6 
48.9 
■ 88.7 
82.4 
32.5 
93.3 
96.9 
47.6 
26.6 
Acala— 
78.6 
Vegetative branches 
92.0 
Season of 1925: 
Pima — 
Main stalks 
25.2 
34.4 

Vegetative branches 
Acala— 
79.6 
84.6 
83.9 
53.0 
33.3 
Vegetative branches 
57.1 
DEVELOPMENT OF BOLLS ON SPECIFIC NODES OF FRUITING 
BRANCHES 
The length of time required for bolls to mature on specific nodes of 
the fruiting branches on the main stalks of both varieties was deter- 
mined in 1924 and 1925 in order to compare the periods of bolls 
which began developing on the same date when these bolls were 
located on inner and outer nodes. These boll periods are given in 
Table 16. No periods are given in the last 10-day interval for Pima, 
as some of the bolls which developed from squares of this interval 
were injured by an early frost which affected their normal opening. 
The bolls of Acala developed from squares coming in this same 
interval escaped injury, as the shorter square and boll periods allowed 
the bolls to reach maturity earlier and to open before the frost came. 
In comparing the records of the two years the boll periods in 1925 
are seen to have been materially longer than in the previous season. 
Some lengthening of the boll periods possibly was caused by the 
plants having to develop a larger number of bolls than in 1924. 
Also several rains which fell while the cotton was opening and a flood 
on September 19 which held the field under a foot of water for a day 
and a half caused excessively high humidity in the field and undoubt- 
edly contributed a great deal to the slower maturing of the crop. 
Comparing the boll periods of inner nodes with those of outer 
nodes in each variety, numerous cases may be observed where 
the outer node had a significantly longer period than the inner node, 
and as was found in determining the square periods of specific nodes 
the boll period seems to be lengthened the farther out on the fruiting 
