Introduction ... 503
The allelomorph Ab ... 504
The allelomorph ap ... 505
Dominance ... 508
Summary ... 508
Literature Cited ... 50

Anderson, E. G.

Emerson, R. A.

English

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Agronomy & Horticulture -- Faculty Publications Agronomy and Horticulture Department
1932
The A Series of Allelomorphs in Relation to
Pigmentation in Maize
R. A. Emerson
University of Nebraska-Lincoln
E. G. Anderson
California Institute of Technology
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Emerson, R. A. and Anderson, E. G., "The A Series of Allelomorphs in Relation to Pigmentation in Maize" (1932). Agronomy &
Horticulture -- Faculty Publications. 913.
http://digitalcommons.unl.edu/agronomyfacpub/913
THE A SERIES OF ALLELOMORPHS IN  RELATION 
TO PIGMENTATION I N  MAIZE' 
R. A. EMERSON 
Cornel1 University, Ithaca, New York 
AND 
E. G. ANDERSON 
California Institute of Technology, Pasadena, California 
Received March 10, 1932 
TABLE O F  CONTENTS 
PAGE 
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . . . . . . . . . .  503 
The allelomorph A b .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
The allelomorph ap. .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  
Dominance. . . . . . .  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  508 
SUMMARY.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  508 
LITERATURE CITED. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  509 
ALEURONE COLOR 
WITH CRPr 
INTRODUCTION 
The inheritance of anthocyanin, flavonol, and related pigments in 
maize is dependent upon a number of genetic factors. Descriptions of char- 
acters and their factorial interrelations have been presented in previous 
publications on aleurone color (EMERSON 1918), general plant color 
(EMERSON 192 1), silk color (ANDERSON 192 1), and pericarp color (ANDER- 
SON and EMERSON 1923, ANDERSON 1924, MEYERS 1927). Some of the 
more important factorial relations are shown in table 1. 
TABLE 1 
Factorial relations of plant, aleurone, pericarp, and silk colors. 
SlLK COLOR 
PERlCARP COLOR WITH -1 WlTHPSnz QENES PLANT COLOR 
Purple 
Dilute purple 
Sun red 
Dilute sun red 
Brown 
Green 
Green 
Green 
I I I 
Purple 
Purple 
Purple 
Purple 
White 
White 
White 
White 
Red 
Red 
Red 
Red 
Brown 
Brown 
Brown 
Brown 
Cherry 
Cherry 
White 
White 
Brown 
Brown 
White 
White 
Salmon 
Salmon 
Salmon 
Salmon 
Green 
Green 
Green 
Green 
* These pericarp colors are absent with homozygous p .  Other allelomorphs of P give varie- 
t The cherry-brown pericarp colors do not appear even in the presence of Pi with any combi- 
Paper No. 186, Department of Plant Breeding, CORNELL UNIVERSITY, Ithaca, New York. 
gated red or brown Pvv, red or brown cob with white (colorless) pericarp Pw, etc. 
nation of the allelomorphs of R lacking rch. 
GENETICS 17: 503 S 1932 
504 R. A. EMERSON AND E. G. ANDERSON 
Other genetic factors also affect these pigments. The recessive gene b, 
gives brown pericarp instead of red but does not affect aleurone or plant 
color (MEYERS 1927). A recessive gene found by Doctor M. T. JENKINS 
resembles a in its effect on aleurone and plant color but apparently does 
not affect red pericarp color. The P, p ,  factor pair differentiates bluish 
purple from reddish color of anthocyanin, most noticeable in the aleurone. 
These genes are all independent of A .  
The pigments involved in chocolate pericarp (ANDERSON and EMERSON 
1931) and in brown midrib (JORGENSON 1931, BURNHAM and BRINK 1932) 
seem to be unrelated to the anthocyanin, flavonol, and pericarp pigments 
dealt with in this paper. 
THE ALLELOMORPH A I 
The source of the allelomorph A b  was a maize with brown pericarp from 
Ecuador. This brown was found to be dominant to red pericarp and a note 
on its inheritance has been published (ANDERSON 1925). At that time tests 
of its re1atio.n to a had not been completed. Since then tests have been 
made showing the absence of any recombination between Aa and the 
gene for dominant brown pericarp. The data are summarized in table 2. 
TABLE 2 
Summary  of data on  the relation of dominant b r o w  pericarp to the a factor. 
The classification for A and a was made on aleurone color but was 
checked by plant color. The white pericarp in these cultures was due to 
the segregation of p ,  and may be disregarded since p is independent of a 
(shown by the data itself and by other records) and of the factor for 
brown pericarp (ANDERSON 1925). The total absence of red pericarp color 
on plants from seeds with colored aleurone shows that there is no recom- 
bination between brown pericarp color and the A factor. The gene for 
dominant brown pericarp is apparently an allelomorph of a and is desig- 
nated by the symbol Ab.  
PIGMENTATION I N  MAIZE 505 
Homozygous A b  C R seeds have colored aleurone. Reciprocal crosses 
with recessive a also give colored aleurone, not distinguishable from the 
corresponding crosses of A with a. Homozygous A and heterozygous 
Ab a with the various combinations of B and Pz give typical purple, dilute 
purple, sun-red, and dilute sun-red plants. Thus A b  appears to be identi- 
cal with A in its effect on aleurone and plant colors. 
From intercrosses of dominant brown pericarp with salmon silk red 
pericarp, backcrossed to salmon silk red pericarp plants, only three classes 
are obtained, as follows: 
Brown pericarp green silks 
Red pericarp green silks 
Red pericarp salmon silks 
Some of the brown pericarp plants when selfed give 25 percent of salmon 
silks; when crossed to salmon they give 50 percent of salmon. In these 
cultures all salmon silk plants have red pericarp, and all green silk plants 
have brown pericarp. These are homozygous sm s, the salmon silk color 
being suppressed by Ab.  This is to be expected if the salmon silk color is 
due to an extension of the red pericarp pigment into the silks. A small 
amount of brown pigment in the silks would be entirely masked by the 
chlorophyll and carotinoid pigments present. 
Thus A b  may be described as the equivalent of the normal A in its effect 
on the anthocyanin pigmentation of the plant; but it converts the red 
pericarp pigment into a corresponding brown pigment. In the latter effect 
it is dominant to A .  
A dominant brown pericarp similar to that discussed here has been 
isolated from maize (C. I. 501) collected by RICHEY and EMERSON at 
Huancayo, Peru, in 1924. 
THE ALLELOMORPH U P  
Another dominant brown pericarp came from the maize collection 
made in 1924 by RICHEY and EMERSON. An ear with cherry pericarp and 
purple aleurone (C. I. 499-2) was obtained at Huancayo, Peru. An indi- 
vidual grown at Ithaca, New York in 1925 from seed of this ear had purple 
plant color (apparently A B Pz) but produced no ear. Pollen from this 
plant crossed onto an individual of an inbred strain of Onondaga White 
Dent, a type with dilute sun-red plant color and white pericarp, A b p z  p ,  
produced an FI progeny of 25 purple plants with cherry pericarp (ap- 
parently A B PL rch)  and 28 sun-red plants (like A B p l ) .  But all plants 
of both color types had brown mosaic pericarp (in addition to cherry in 
GENETICS 17: S 1932 
506 R. A. EMERSON AND E. G .  ANDERSON 
ALEURONE COLOR F, 
STRONG PALE 
CRO8JED 
WITB 
PURPLE PURPLE 
~ _ _ _ _ _ _ _ _ . _ _ _ _ _ _ _  
883 . .  
. .  892 
AP 121 . .  . .  
A P  282 . .  . .  
d R P (  . .  ’ 
case of A B P z  plants) as if the genotype were a PmO. Moreover, in Fz and 
later generations of this cross, brown and green plants appeared as if 
the genotype were a B P L  or a b p,. When such green plants, however, 
were crossed with A-testers, a C R, the resulting aleurone color was pale 
purple rather than white as expected from a a or strong purple as ex- 
pected from A a or Ab a. 
Evidently the Peruvian plant used in this cross carried some gene like a 
with respect to plant color, like A b  with respect to pericarp color, and 
intermediate between A or A b  and a with respect to aleurone color. A 
gene up allelomorphic to A ,  A b  and a with characteristics noted above 
provides a ready interpretation of all the results obtained with this ma- 
terial. 
That Pmo was present in the original Peruvian plant is sufficiently indi- 
cated by the appearance of brown mosaic pericarp in F1 of crosses with 
white pericarp, and only mosaic and white segregates in Fz. Crosses of 
brown mosaic with red self-colored pericarp gave brown self color in F1 
and brown and red self and brown and red mosaic in Fz. 
Peruvian type green plants with brown pericarp apP crossed with green, 
white pericarp A-testers a b p z  p ,  and with brown plants with or without 
pericarp color, a B P z  P or p ,  the Fl’s being recrossed with a C R p or with 
A p ,  gave the results summarized in table 3. These data show that a C R p 
TABLE 3 
Summary of data from a p  and aP XaPP. 
PLANT COLOR PERICARP COLOR 
RED OR GREEN on 
RED WHITE PURPLE BROWN 
I__-p 
. .  74 39 . .  35 
. .  79 47 . .  32 
121 . .  41 30 50 
282 . .  125 157 . .  
X (a  p Xgreen plant brown pericarp) gave approximately equal numbers 
of pale purple and of white and no strong purple aleurone, and that both 
aleurone color types produced only green plants with approximately 
equal numbers of brown and of white and no red pericarp. Also A p X ( a  p 
Xgreen plant brown pericarp) gave only strong purple aleurone, only red 
plants and approximately equal numbers of brown and red pericarp. These 
results indicate the independence of brown and P and show no recom- 
bination of brown and a. 
PIGMENTATION IN MAIZE 507 
FI 
Selfed 
Selfed 
XaCRp 
Green plants with brown pericarp of the Peruvian stock, a p  P crossed 
with A p and A P gave the results shown in table 4. As shown in this 
table, selfed Fl’s gave approximately the expected frequency of strong 
purple and pale purple but no white aleurone. The pale purple seeds pro- 
duced only green plants with brown (or brown and white) pericarp while 
the strong purple seeds gave only red plants some with brown and some 
with red pericarp (and some white when P p ) .  The Fl’sXa C R p gave 
some strong purple aleurone, red plants, and red or white pericarp, and 
about an equal number of pale purple aleurone, green plants, and brown 
or white pericarp. These results establish the independence of brown and 
P and the allelomorphism of brown and A .  
TABLE 4
Summary of data from A p  and APXaPP. 
STRONQ , PALE 
PURPLE PURPLE RED 
GREEN BROWN RED WAITE 
-_______________ -_ 
76 . .  76 . .  28 15 . .  
28 . .  28 10 0 . .  
161 . .  42 18 23 
36 . .  36 17 0 7 
. .  272 . .  0 107 143 
. .  267 112 0 127 
I ALEURONBCOLOR 1 PLANTCOLOR I PERICARP COLOR 
The relation of a p  to salmon silk colors, P sm, has not been determined. 
Its relation to the cherry-brown pericarp colors is apparently the same as 
that of a. Some of the plants of the cross of the original Peruvian plant, 
a p  B PI Pmo R, with Onondaga White Dent, A b p z  p y C h ,  were purple and 
the pericarp of all these was brown mosaic on a background of cherry. 
This indicates that U P  either has the same effect as A or is recessive to it 
as regards cherry pericarp. A reddish brown plant, a p  B P1, which ap- 
peared in a later generation of this cross, crossed with a purple plant having 
cherry pericarp and known to be A a B PZ y c h ,  produced a small F1 culture 
consisting of purple and of reddish brown plants. All the purple plants had 
cherry pericarp, A a p  B Pl rch, and the brown plants had brown pericarp, 
a p  a B PZ y c h .  It is certain, therefore, that, with PI and reh, A a p  gives 
cherry and a p  a gives brown pericarp. Since the allelomorphs A and a are 
related to cherry brown pericarp colors exactly as they are to plant colors, 
A giving purple plants and cherry pericarp and a a green or brown plants 
and brown pericarp and since u p  a P  gives green or brown plants, it is pre- 
sumable that it would also give brown pericarp with PI ych .  
GENETICS 17: S 1932 
508 R. A. EMERSON AND E. G. ANDERSON 
The allelomorph u p  resembles A b  only in its effect on the pericarp pig- 
ment. Like A b  it produces brown pericarp color and is dominant to the 
red pericarp color produced by A .  With C and R it gives a pale purple 
aleurone color instead of the deep color of A and A b  or the absence of 
color with a. In  its effect on plant color it resembles the recessive a except 
that the brown color in combination with B and PI is a reddish brown. 
DOMINANCE 
These four allelomorphs of A do not form a simple series in their domi- 
nance relationships. The sequences from dominant to recessive are as 
follows : 
For aleurone color with C and R 
A and A b  strong purple 
UP pale purple 
a colorless 
For plant color with B and PL 
A and A b  purple 
UP reddish brown 
a brown 
Ab and a= brown (dominant) 
A red 
U brown (recessive). 
For pericarp color 
The interactions of the several allelomorphs of A with various other 
aleurone, plant, pericarp and silk color genes are summarized in table 5 .  
Combinations which have not been tested directly are given in paren- 
theses. 
SUMMARY 
Two new allelomorphs of the A factor for aleurone, plant and pericarp 
color are described. 
A b  resembles the normal A in its effect on the anthocyanin pigmentation 
of the plant; but it converts the red pericarp pigment into a corresponding 
brown pigment. It is dominant to A in this respect. 
The allelomorph u p  resembles Ab in its dominant effect on pericarp 
color. But it gives pale aleurone color with C and R and it is almost like 
the recessive a in its effect on plant color. 
Table 5 gives a summary of the effects of these four allelomorphs in 
combination with the factors C, R, B,  PI, P, and sm. 
PIGMENTATION I N  MAZIE 509 
PLANT COLOR PERICARP COLOR ALEURONE 
COLOR WITH 
CRP, WITR BPI WITH Bp1 W I T H P l t C h  WITH P 
Strong Purple Sunred Cherry Red 
Strong Purple Sunred Cherry Red 
Strong Purple Sun red (Cherry) Brown 
Strong Purple Sun red Cherry Brown 
Strong Purple Sun red (Cherry) Brown 
(Strong (Purple) (Sun red) (Cherry) (Brown) 
Strong Purple Sun red (Cherry) Brown 
Pale Reddish Green Brown Brown 
Pale purple Reddish Green Brown Brown 
White Brown Green Brown Brown 
purple 
purple 
purple 
purple 
purple 
purple) 
purple 
brown 
brown 
ALLBLO- 
YORPAS 
OF A 
BILK COLOR 
WITH PSm 
Salmon 
Salmon 
Green 
(Green) 
Green 
(Green?) 
(Green?) 
(Green?) 
(Green?) 
Green 
A A  
A a  
A A b  
Aap 
AbAb 
A bap 
Aba 
apap 
@a 
aa 
LITERATURE CITED 
ANDERSON, E. G., 1921 The inheritance of salmon silk color in maize. Cornell Agric. Expt. Sta. 
1924 Pericarp studies in maize. 11. The allelomorphism of a series of factors for pericarp 
Mem. 48: 539-554. 
colors. Genetics 9: 442453. 
1925 A dominant brown pericarp color in maize. Michigan Acad. Sci., Arts and Letters 5: 
73-75. 
ANDERSON, E. G., and EMERSON, R. A., 1923 Pericarp studies in maize. I. The inheritance of 
1931 Inheritance and linkage relations of chocolate pericarp color in maize. Amer. Nat. 65: 
BURNHAY, C. R., and BRINK, R. A., 1932 Linkage relations of a second brown midrib factor in 
EMERSON, R. A., 1918 A Bth pair of factors A a, for aleurone color in maize, and its relation to 
1921 The genetic relations of plant colors in maize. Cornell Agric. Expt. Sta. Mem. 39: 1-156. 
JORGENSON, L. R., 1931 Brown midrib in maize and its linkage relations. J. Amer. Soc. Agron. 23: 
MEYERS, MARION T., 1927 A second recessive factor for brown pericarp in maize. Ohio J. Sci. 
pericarp colors. Genetics 8: 466476. 
253-257. 
maize. (Manuscript.) 
the C c and R r pairs. Cornell Agric. Expt. Sta. Mem. 16: 225-289. 
549-557. 
27: 295-300. 
GENETICS 17: S 1932 


The \u3ci\u3eA\u3c/i\u3e Series of Allelomorphs in Relation to Pigmentation in Maize

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The \u3ci\u3eA\u3c/i\u3e Series of Allelomorphs in Relation to Pigmentation in Maize

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