Hayes and Garber - Cucurbit Breeding

CLASSIFICATION AND INHERITANCE OF SMALL GRAINS 93
rity at which the grain is harvested or weathering after harvesting
may also modify these color characters.
The color of the lemma of oats has been classified as black,
brownish red, gray, yellow, and white. Different varieties,
likewise, exhibit different intensities in the development of a
particular
color. In some crosses between black and white a
ratio of 15 blacks to 1 white was obtained in F 2 ^Nilsson-Ehle,
1909), while the majority of crosses show 3:1 ratios (Nilsson-Ehle,
1909), (Gaines, 1917). The simplest explanation
is that each
color character is due to one or more factors, each factor when
heterozygous causing partial or complete development of the
character.
Results of crosses show that yellow is dominant over white
or partially so. There are, however, two yellow factors each
independently inherited. In a cross between Burt, which
produces yellowish red seeds, and Sixty Day, which produces
yellow seeds, Frazer (1919) obtained a ratio of 48 red, 15 yellow,
and 1 white in F ? .
These results may be explained by supposing
Burt to carry two color factors, R for red and Y for yellow, and
Sixty Day one factor, Y l for yellow.
either when associated with Y or F 1
Apparently R produces reds
or when alone.
Gray is epistatic to yellow (Nilsson-Ehle, 1909) (Surface, 1916)
(Love and Craig, 1918c) but hypostatic to black, while black is
epistatic to all other colors so far as determined. It has been
tested for gray, yellow, and white but not for brownish red. As a
rule the intensity of color is not so great when a factor for a particular
color is heterozygous as when homozygous.
The inheritance of a reddish straw color has been shown
by Pridham (1916) to behave as a simple Mendelian monohybrid.
Hulled versus Hull-less. The hull-less condition has been
made the basis of one of the species groups, Avena nuda. Numerous
crosses between hulled and hull-less forms have given like
results. All investigators of these crosses have obtained an
intermediate condition in FI, with both kinds of grains, hulled
and hull-less, borne in the same panicle. Ratios in Fz of 1 of
each of the hulled and hull-less forms to 2 heterozygotes have
been obtained. The hulled and hull-less types breed true while
the intermediates again segregate. Love and McRostie (1919)
have found considerable variation in the percentage of hulled and
hull-less seeds in different panicles of the same cross. Consistent
correlation was obtained between the percentage of hulled