Hayes and Garber - Cucurbit Breeding

106 BREEDING CROP PLANTS
Wild rye,
SOME RYE STUDIES
Secale montanum, differs from cultivated rye
in its
perennial habit. Tschermak (1914) finds that wild and cultivated
forms may be easily crossed, which indicates rather close
relationship.
Rye (see page 40)
it is cross-pollinated. Sterility
differs from the other small grains in that
is often obtained when selffertilization
is attempted. For this reason it is not easy to
produce homozygous strains and therefore few inheritance studies
have been made.
Xenia in rye was first discovered by Giltay in 1893. It was
later corroborated by Von Rumker and others (1913, 1914).
strains have been produced which are
By continuous selection,
pure for color differences. According to Von Rumker, selection
for seven or eight years was necessary in order to isolate strains
which were homozygous for color of seed. He found the color
to be located in the aleurone layer just inside the epidermis.
There are numerous colors of rye which are roughly analogous to
the aleurone colors of corn. The inheritance of these colors has
not as yet been intensively studied.
Von Rumker has isolated
pure races for greenish blue, deep brown, and yellow seed.
There are also deep blue, light brown, and striped seed besides
other color variations. In crosses between green- and yellowseeded
strains Von Rumker found green dominant and obtained
a ratio of 3 green to 1 yellow in F*.
There are both spring and winter varieties of rye.
The spring
habit appears to be a dominant character, for Tschermak (1906)
of 3 spring forms to 1 winter form.
obtained a ratio in F z
Wheat-rye Hybrids. Numerous investigators (Backhouse,
1916-1917 ;Leighty, 1915, 1916; Jesenko, 1911, 1913; McFadden,
1917) have reported crosses between wheat and rye. In all
reported successful crosses, wheat has been used as the female
parent. Rye is very winter hardy and as winter wheat is much
less hardy it is only natural to try to improve winter wheat by a
rye-wheat cross. As a rule the FI cross is self-sterile, although
back crosses with the parents have sometimes been successful.
Love and Craig (1919 a) have described a successful wheat-rye
cross, using Dawson's Golden Chaff as the wheat parent. Studies
have been continued through F 4 and F 5 and a number of
plants have been obtained which exhibit little or no sterility.