330 LINDSTROM, GENETICAL RESEARCH WITH MAIZE 
plete linkage or of multiple allelomorphs. At present the latter expla- 
nation appears to offer the simplest solution.) 
A list of the more common pericarp and cob colors follows :— 
Pericarp Cob Genetic symbols 
Red Red APR 
Orange 4 AFP 
White à An Der 
Orange White PRE 
Red (white capped) H PSP 
Variegated (red) Variegated Al ait Oe 
White White A p 
In the above arrangement 4 merely indicates that a general anthocy- 
anin factor must be present for the red series. When aa is present in 
this same arrangement brown color replaces the red in both pericarp and 
cob. This Aa factor pair is the same general factor pair that is funda- 
mental in aleurone and plant color as will be seen later. 
Any one of the seven color combinations noted above is inherited as 
a simple allelomorph to any other. For example red-red (red pericarp- 
red cob) crossed with white-white, produces red-red ears in F,, and in F, 
3 red-red to 1 white-white. Red-white (white capped red pericarp-white 
cob) X white-red gives in F, red-red and in F,, | red-white: 2 red-red: 
I white-red. Likewise red-white x white-white, shows in F, approxima- 
tely 3 red-white: 1 white-white. The variegated (each grain striped red 
and white) type is a simple recessive to red-red, and dominant to white- 
white. ; 
Number of rows. — In normal maize there are two general situations 
with respect to the arrangement of the grains on the ear. By far the 
greater majority of commercial varieties of maize are characterized by 
a regular arrangement of the kernels in paired rows from butt to tip. In 
only one commercial variety (Country Gentleman sweet corn) is there 
a different arrangement. Here the grains are conspicuous by their irre- 
gular distribution on the ear. | 
1) This situation has been developed by Dr. R. A. Emerson of Cornell Univer- 
sityand Dr. E.G. Anderson, but the results have not yet been published in detail. 
Dr. Emerson has referred to the situation in several papers (1917 and 1920), and 
the material is now in manuscript form (Anderson 1923). 
