Hayes and Garber - Cucurbit Breeding

84 BREEDING CROP PLANTS
nuclei, there may be a range of from to 6 factors for starchiness
of the endosperm. This assumption was shown to explain results
quite satisfactorily. The above starchiness is believed by Freeman
to be quite different from the well-known "yellow berry" of
wheat. Numerous workers have shown that varieties and strains
differ widely in the amount of "yellow berry" when grown under
the same environmental conditions. Texture of seed is, however,
a character which is quite easily modified by unfavorable environmental
conditions.
Chaff Characters.
of the chaff color.
There are a number of different intensities
In some cases a deep brownish red color is
present, in other cases a light brownish-red, and frequently the
outer glumes have dark brownish red striations on a slightly
colored or colorless background. Biffen (1905) studied crosses
between so-called red and colorless and obtained red or reddish
color in FI and a 3:1 segregation of colored to colorless in F 2 .
Kezer and Boyack (1918), in winter wheat crosses in which the
parents differed in chaff color, obtained intermediate color in FI
and segregation in a 3:1 ratio in F 2 .
Simple ratios in varietal
crosses have been reported by others for this color character.
As there are different intensities which are quite uniform in inheritance
it seems reasonable to conclude that there are different
factors in different varieties for brownish-red color. In a durumvulgar
e cross, Love and Craig (1918a) obtained in F% an indication
of a 15: 1 ratio for brownish red and colorless chaff.
Besides the chaff colors there are awn colors.
The Howards
(1915), in India, obtained a ratio in F 2 of 3.45 black-awned to 1
colorless in a cross between Indian wheats.
Hairy chaff is a varietal character of considerable classification
value. The Howards have made extensive studies of this
character. Under linkage relations a number of cases were
given in which hairy chaff was correlated with glume color.
Henkemeyer (1915) reports different crosses, one in which hairy
chaff is correlated with white chaff and another in which these
characters are independently inherited. This leads one to suspect
that there are two kinds, either of hairy chaff or of chaff color.
The Howards have been able to demonstrate two kinds of hairs
on the glumes of Rivet wheat. Two Indian varieties were likewise
studied. Each produced hairy chaff, but differed in the
sort of hairs produced. In crosses between these varieties,
ratios of 15 pubescent to 1 smooth were obtained in F 2 .