42 BULLETIiiT 1074, IT. S. DEPARTMENT OF AGRICULTURE. 
mottled, the condition being designated as "yellow berry," and are 
then rather soft. 
The difficulty of the numerous investigators in determining the 
kernel texture has been due to the failure to dissociate softness from 
starchiness or ^^ellow berry. Freeman {91) has shown the nature 
of hardness in the wheat kernel. The following is quoted from 
his conclusions: 
1. Tlie hardness of a wlieat is determined by the solidity of the grain, and 
this, in turn, by the nature and relative proportions of gluten and starch in 
the endosperm. 
2. When the ratio of gluten to starch is sufficiently high, the entire cell 
contents are cemented together solidly as the grain dries out in ripening. 
It, therefore, takes on a hard, glassy, semitranslucent texture. In the ab- 
sence of a sufficient proportion of gluten to hold the cell contents together, 
the shrinkage in drying does not fully compensate for the loss of water, and 
air spaces appear within the cells. These oi^en spaces render the grain soft 
and, also, since they serve as refracting surfaces, make it opaque. We are, 
therefore, accustomed to associate softness, opaqueness, and low gluten con- 
tent in wheats. 
3>. There are two types of soft grains among the wheats included in these 
exi^eriments. 
(a) A type designated by the writer as "true softness,'' in which the 
air spaces in the endosperm are diffuse and finely scattered. This type 
of softness is only slightly affected by environic conditions. 
(&) A type commonly called "yellow berry," in which the air spaces within 
the endosperm occur in flakelike groups with quite definite margins. The 
opaqueness thus arising may be confined to a small spot only or may include 
the entire endosperm. This type of softness is very sensitive of environic 
conditions. 
In this bulletin soft texture refers to the condition designated above 
as " true softness ''' and must not be confused with yellow berry. 
True kernel texture, therefore, can not be determined on yellow- 
berry kernels, because they always are soft. It usuall}^ is possible, 
how^ever, to select from a sample a few kernels which are not wholly 
starchy and which can be accurately used for texture determinations. 
Koberts {159) has attempted to measure hardness mechancially by 
determining the crushing strength. This is not entirely accurate, 
as the shape of the kernel influences its crushing strength and, in 
addition, so ft- wheat varieties grown under dry-land conditions are 
quite brittle and difficult to crush. Texture is determined by cutting 
kernels which are not affected b}^ yellow berry and examining the 
endosperm. 
SHAPE OF THE KERNEL. 
The shape of kernel outline is described as ovate, elliptical, or 
oval. These terms refer only to the outline of the kernel as viewed 
from the dorsal surface, and not to the kernel as a whole. When 
egg-shaped in outline, the germ end being the broader, it is described 
