EN 
LINDSTROM, GENETICAL RESEARCH WITH MAIZE 999 
(1914) and Kempton (1919) show a 9 : 3 :4 ratio in F, from an F, Su 
su Wx wx as follows: — 
» 
9 Su Wx — starchy 
3 Su wx — waxy 
3 su Wx — sugary 
1 su wx — 
22 
The inheritance of dent, flint, and pop endosperm when intercrossed 
does not show a simple relationship. These crosses may be interpreted 
in terms of quantitative inheritance. 
The flour corns seem to give a fairly distinct genetic behavior when 
crossed with the flint type. There is a pronounced cumulative effect of 
the simple factors concerned. Due to the triple fusion in the embryo- 
sac of maize, there are four different genotypes in a cross of flour X 
flint corn. Two doses of either type overbalance one dose of the other 
as follows: — 
Fl Fl Fl — flint 
Fl Fl fl — 
fl fl Fl — flour 
a, 
The F, ratio of such a cross accordingly shows a 1 : 1 ratio of flinty 
to floury seeds. (Hayes East 1915). | 
As a result of much inbreeding in maize a large number of abnormal 
or defective types of endosperm have been isolated. Being recessive in 
inheritance they have been accumulating in the maize species for long 
periods of time. Since maize is so completely cross-fertilized it would be 
practically impossible to eliminate such abnormal types by natural se- 
lection or even by artificial mass selection. Accordingly they are sur- 
prisingly numerous even in the best varieties of maize. 
Defective endosperm. — Hereditary defects in the endosperm of maize 
have been reported by Jones (1920) and Lindstrom (1920 and 1923). 
They have been shown to be inherited as simple recessives in some Ca- 
ses. There is a multiplicity of different types (phenotypically and ge- 
notypically). In some the endosperm is only partly defective, the 
grains being slightly smaller in size. In others the defective nature 1s 
