May 10, 1924 
u Hairy Neele” Wheat Segregates from Hybrids 
569 
is limited to a few hairs which are difficult to distinguish without magnification. 
Rye plants with glabrous peduncles are sometimes found. The percentage of 
such plants is usually very small, but there apparently are varietal differences in 
regard to this factor despite the fact that the rye plant is almost entirely cross- 
pollinated. The necks of four typical rye heads are shown in Plate 2. 
In Table II are given the data obtained on eight varieties of winter rye for the 
crop year 1922-23, in regard to the hairiness of the neck as seen by the naked eye. 
In five of the eight varieties, less than one per cent of glabrous-necked culms were 
found, while in von Riimker No. 2 there were 8 per cent. The total for all 
varieties was 1.9 per cent glabrous-necked culms. Gaines and Stevenson {3) 
report 66 per cent hairy-necked plants among 41 plants of Rosen rye examined at 
Pullman; Wash. 
Table II .—Number and per cent of glabrous-necked culms found in eight varieties 
of winter rye at Arlington Experiment Farm in 1923 
Variety 
Number 
of 
Glabrous-necked 
culms 
Variety 
Number 
of 
Glabrous-necked 
culms 
culms ex¬ 
amined 
Number 
Percent¬ 
age 
culms ex¬ 
amined 
Number 
Percent¬ 
age 
Von Riimker No. 2. 
600 
40 
8.0 
Winter. 
638 
5 
0.8 
St. Johns.... 
484 
7 
1.4 
Abruzzes_ 
643 
4 
. 6 
Rosen_ . 
Virginia 
1,363 
490 
480 
1,289 
45 
3 
4 
16 
3.3 
.6 
.8 
1.2 
Von Riimker No. 1. 
700 
4 
.6 
Rim pau.. 
Mexican .. 
Total_ 
6, 587 
128 
1.9 
The Fi wheat-rye hybrid is approximately intermediate between the two 
parents in such characters as shape and density of head, number of spikelets, 
width and other characters of the empty glumes, and in general appearance 
(PI. 1). The hairy-neck character of rye, however, is usually expressed in the 
Fx and apparently is a dominant character in this generation. About 300 first 
generation wheat-rye hybrid plants, nearly all natural hybrids, growing at the 
Arlington Experiment Farm, have been examined with reference to this char¬ 
acter. Approximately 80 per cent of these have had the hairy neck in the 
varying degrees as found in rye. The glabrous-necked plants in the F x may be 
due to the gametic constitution of the rye parents in these cases in respect to 
this character. 
INVESTIGATIONS ON HAIRY NECK 
Plants resembling wheat in most characters, but having the hairy neck, were 
observed in the F 2 and subsequent generations arising from the natural hybrids 
found in 1918. Investigations on this character were begun in 1920, when a 
cross was made between Purplestraw wheat and a wheat-like F 3 segregate of a 
wheat-rye hybrid. The pollen parent of this hybrid, the F 3 segregate, appar¬ 
ently carried the factor for hairy neck in heterozygous condition, for, from the 
8 kernels resulting from this cross, 7 glabrous-necked plants were produced and 
only 1 with hairy neck. The progeny of this hairy-necked plant in 1922 con¬ 
sisted of 36 glabrous-necked plants and 2 with hairy necks. Data on the progeny 
of these 2 hairy-necked plants obtained in 1923, are given in Table III (A and B). 
In addition to these 2 plants, 8 other plants having the hairy neck were selected 
in 1922 from the F 6 progeny of the natural wheat-rye hybrids found in 1918, 
Data on the plants produced in 1923 from the seed of these 8 plants are given 
in Table III (C to K), and 3 of the heads, together with a head of Fulcaster 
wheat for comparison, are shown in Plate 3. 
