134 The Journal 
to pollinate or control the pollination of 
any of the flowers. It is not known 
whether the seeds formed are due to 
self-fertilization or to fertilization by 
wheat or rye pollen from neighboring 
plants. 
The spikelets of the hybrid plants are 
from three to five flowered, as in wheat. 
Rye has two flowers, rarely three, to a 
spikelet. The shape and size of glumes 
and lemmas, the several-nerved glumes 
with ciliate keel as found in the hybrids, 
all furnish evidence that these are in- 
deed first generation. hybrids between 
wheat and rye. 
The conclusion is inevitable that the 
plants found and here described are first 
generation hybrids of wheat and rye, 
the seeds from which they grew having 
been produced by the natural fertiliza- 
tion of wheat flowers with rye pollen. 
THE STERILITY OF WHEAT-RYE HYBRIDS 
The nineteen hybrid plants found on 
Arlington farm bore about 3,500 flowers 
while only forty seeds were produced. 
About 1% of the flowers on these 
plants set seed. Hybrid No, 14 pro- 
duced twenty-two seeds, a fertility of 
about 5% of the flowers. This percent- 
age of setting seed is considerably larger 
than in my previous natural and artifi- 
cial hybrids of wheat and rye. One ar- 
tificial and seven natural F, hybrids pre- 
viously examined bore about 1,500 flow- 
ers, yet only two seeds were produced, 
or less than a tenth of 1% of the 
possible seed production. 
Several other experimenters have re- 
ported a small amount of fertility in 
the first generation hybrids of wheat 
and rye. Carman* secured nineteen 
seeds on ten heads of such a plant, from 
which he grew large numbers of plants 
of Heredity 
of later generations and finally intro- 
duced a wheat variety probably de- 
scended from this cross. Rimpau® har- 
vested several seeds from a first genera- 
tion, open-pollinated plant derived by 
crossing the red Saxony wheat and 
Schlanstedt rye, from which he grew 
plants of later generations. Wheat 
forms segregating out were distributed 
by him and were grown for several 
years by several persons and are prob- 
ably still grown at certain European 
experiment stations. 
Miczynski® harvested some seed from 
a first generation plant, but apparently 
was not able to get beyond the third 
generation because of sterility. Jes- 
enko? describes four generations de- 
scended from certain wheat-rye hybrids 
made by him, Nakao® states that a 
“few seeds, generally one seed to a few 
ears,” were obtained from an F, hybrid, 
but he could not be certain whether 
or not they were due to fertilization 
by the pollen of the hybrid. 
Love and Craig,® in their work at 
Cornell University, have secured two 
fertile wheat-rye hybrids that have now 
been carried beyond the fourth genera- 
tion. 
McFadden"® also reports the produc- 
tion of three seeds on an F, wheat-rye 
hybrid plant with twenty-five heads, 
following the pollination of a few late 
spikes with wheat pollen. The plants 
of the F, generation winterkilled. 
There are probably others who have 
secured viable seed from F, wheat-rye 
hybrids. Many others are known to 
have effected the hybrid between these 
species of cereals, but found the F, en- 
tirely sterile. From these instances of 
partial fertility it is evident that seed 
is occasionally formed, but practically 
4For an account of Carman’s wheat-rye hybrids see article by C. E. Leighty, in 
JourNAL oF Herepity, Vol. 7: 420-427. 1916. 
5Reference to Rimpau’s hybrid is made in Fruwirth, C., Die Ziichtung landwirtschaftli- 
chen Kulturpflanzen, Band 4, p. 183. Berlin, 1910. 
5Miczynski: Kosmos r, xxx Lwow. 1905. 
Citation from Fruwirth loc. cit. 
7Jesenko, F., Uber Getreide—Speziesbastarde (Weizen-Roggen) Zeit. fiir Induk Abs. 
u. Vererbungslehre, 10: 311-326. 1910. 
8Nakao, M., “Cytological Studies on the nuclear division of the pollen mother-cells of 
some cereals and their hybrids,” Jour. of the Col. of Agri. 
9Love, 
Vol. 9: 67-76. 1918. 
Sapporo, Japan, 4: 173-190. 1911. 
H. H., and Craig, W. T., “Small Grain Investigations.” JourNAL or HeErepIty, 
10McFadden, E. A. “Wheat-rye hybrids. Journar or Herepity, Vol. 8: 335-336, 1917. 
