572 
Journal of Agricultural Research 
Vol. XXVIII, No. 6 
kernels are narrower, blunter at the base, and have longer and more sharply 
pointed germs than the kernels from the oblong head. The longer, narrower 
glume of the fusiform head no doubt influences the shape of the grain, but whether 
or not the glume character can be attributed to the F! rye parent is open to ques¬ 
tion. According to Fruwirth (2, p. 188-184), a segregate somewhat similar to 
this fusiform type resulted from a wdieat-rye hybrid made by Rimpau in 1888. 
It was largely wheat-like, but in comparison to wheat the head and glumes were 
longer, the latter closely pressed together, and the keel ciliated as in rye. This 
strain was grown for many years in an experimental way in Europe and remained 
fully constant in all respects, including a partial sterility exhibited by it. 
DISCUSSION AND SUMMARY 
It is evident that the hairy neck found in wheat-like segregates of wheat-rye 
hybrids is a heritable character, but the data at hand are not sufficient to permit 
definite conclusions regarding the number of factors involved or the manner in 
which these factors are transmitted. Considerable irregularity in segregation is 
apparent and both dominant and recessive tendencies are observed. The reason 
for this is unknown, but it is suspected that it is related to probable irregularities 
in chromosome behavior. 
According to Sakamura (11), Triticum vulgare has 21 and Secale cerealel haploid 
chromosomes. These numbers have been confirmed by Sax (12), The number 
of chromosomes in the F x of the hybrid between these species has not been deter¬ 
mined. Nakao (10), who made cytological studies of the Fi of a wheat-rye 
hybrid, states that “the chromosome number is not definite (17-23), being almost 
always more than the expected number, 16.” 3 From our present knowledge of 
chromosome numbers in these species as given by Sakamura (11) and Sax (12), 
we would expect 28 chromosomes in the F x , 21 from the Triticum vulgare parent, 
and 7 from the Secale cereale. This would be in accord with the observation of 
Kihara (5 ), who found 35 somatic chromosomes in the F x of hybrids between differ¬ 
ent members of the “Emmer group” of wheat, which contain 14 gametic chromo¬ 
somes, and members of the “Vulgare group” of wheat, 'which contain 21 gametic 
chromosomes. Sax (12) also observed 35 chromosomes in hybrids between these 
groups, while in an Fi hybrid between T. monococcum with 7 gametic chromo¬ 
somes and T. turgidum with 14, the F x had 21 somatic chromosomes. In the 
Fi hybrid between the “Emmer” and “Vulgare” groups, according to both 
Kihara and Sax, 14 pairs of chromosomes and 7 univalent chromosomes are found 
in the pollen mother cell. The 14 pairs, as stated by Sax, “divide as usual in 
meiosis while the 7 univalents lag behind but ultimately divide equationally in 
the first division, and pass at random, without dividing, to either pole in the 
homoeotypic division.” As a result of these abnormalities, Sax estimates that 
20 per cent of the pollen produced is obviously imperfect and a large percentage is 
nonfunctional. Considerable sterility is found in these hybrids between the 
groups of wheat. • 
If such phenomena should occur in the wheat-rye hybrid there would be 7 
bivalent and 14 univalent chromosomes in the Fi generation. With the higher 
number of univalents and the increased ratio of these to bivalents, abnormalities 
in chromosome behavior would be expected to occur in even greater degree than 
in the hybrids between different groups of wheat. Furthermore, with the 
gametes effecting the hybrid having come from plants belonging to different 
genera, incompatibility between the chromosomes contributed by the respective 
parents could hardly fail to exist. The results of Nakao (10) confirm this expecta- 
8 Nakao states: “In wheat, as described by Overton and Koernicke, and in rye, the reduced number of 
chromosomes is 8.” 
