May 10, 1924 
u Hairy Neele” Wheat Segregates from Hybrids 
571 
This is the ratio that would be expected if the hairy-neck character is recessive. 
But in the different progenies the ratios of hairy-necked to glabrous-necked plants 
varied from 1 to 12.2 in selection E to 2.4 to 1 in selection I. Furthermore, all of 
the parent plants had hairy necks. Therefore, the character does not appear to 
be recessive. 
The hairy-neck character, however, has not been consistently dominant, as is 
evident from data given above. Nevertheless, at least a high degree of dom¬ 
inance occurs in the F x . Additional data on the F 2 generation of wheat-rye 
hybrids also are at hand. One lot of such plants grown by the writers in 1923 
consisted of 21 with hairy necks and 8 with glabrous necks. These were descended 
from 24 natural hybrids, all with hairy necks, and all open-fertilized. Gaines and 
Stevenson (3) report that in the F 2 they obtained 11 plants with hairy necks and 
4 with glabrous necks. 
POSSIBILITY OF NATURAL CROSSING 
It is known that natural crossing occurs to some extent in wheat-rye hybrids. 
The data presented in Table I indicate that fertility in the Fj is dependent on 
pollen from outside sources and not on self-pollination. The plants used in this 
study of the hairy-neck character were open-fertilized throughout the experiment, 
as were also all parental plants in preceding generations. In 1923, however, 
heads to be used in further studies were selfed by bagging. In this connection it 
should be noted that the percentage of fertility of 21 bagged (selfed) heads, 
excepting 2 in which the fertility for some reason was low, was 77 per cent, while 
the percentage of fertility of 21 unbagged (open-fertilized) heads, was 79 per 
cent. Some of the selected heads, both selfed amd open-fertilized, showed 
higher fertility than Purplestraw wheat, which varied from 80 to 85 per cent, 
but others were somewhat less fertile. 
The progenies of the selections listed in Table III do not disclose a large 
amount of natural crossing. All plants in 5 of the 10 progenies were identical 
with their respective parents in head characters. Four of the progenies each 
contained one individual that appeared from its head characters to be due to a 
natural cross on the parent selection, the off-type plant in each case differing from 
the parental selection in degree of awn development and in glume color. 
Considerable natural crossing was evident in only one progeny (K), which 
consisted of 84 awned and 14 semiawned plants. These plants lacking full 
development of awns, in the progeny of an awned plant, indicate natural crossing 
with pollen from an awnless plant, inasmuch as the factor for presence of awns in 
wheat normally is incompletely recessive to the factor for their absence, which 
results in a semiawned plant in the F x . In spite of this evidence of natural 
crossing all plants in selection K were hairy-necked. There is perhaps a slight 
possibility that the different head characters appearing in this progeny, likewise 
also in the other cases noted, are not evidence of natural crossing but indicate 
some unusual factorial composition of the gametes, resulting«in abnormal segre¬ 
gation. 
In addition to the differences in respect to awns, the progeny of selection K, 
though consisting entirely of hairy-necked individuals, also differed somewhat in 
head type, as is shown in Plate 5. All heads had white or yellow glumes, but one 
type had a lax, fusiform spike, while that of the other was more dense and oblong 
in shape. The width and shape of the shoulder of the outer glume, as well as the 
length of the beak, differed greatly, as ma}' be seen from the figure. 
In Plate 2 are shown the kernels obtained from one head each of Abruzzes rye, 
Fulcaster wheat, and the fusiform and oblong types of head present in selection 
K. Resemblance to rye may be seen in the seeds from the fusiform head. The 
