86 R. A. EMERSON 
either A a or Cc. An Fs sun red plant with green anthers, R’ R’, had§j 
97 colored and 20 colorless seeds, again indicating either A a or Cc. If it 
was AA BbCcR! R’, both colored and colorless seeds should have 
given sun red and green plants in a 3:1 ratio; if it was Aa BBCC R'R’,§ 
the colored seeds should have given sun red and the colorless ones green) 
plants only, the plant-color ratio again being 3:1; but if it was A a B bff 
CC R® R’, the colored seeds should have produced sun red and greenf 
plants in a 3:1 ratio and the colorless seeds green plants only, the ratioff 
of sun reds to greens in the two lots together being 9:7. Actually the 
colored seeds resulted in 23 sun red and 10 green plants and the colorlessi 
seeds in 10 green plants only, the ratio of sun reds to greens being 23: 20,8) 
thus approaching 9:7. There is, therefore, considerable assurance that 
the F3; plant was Aa BbCC R’ R’, that the F. plant was Aa BbCC§ 
R’ 7", and that the F3 numerical relation of plant colors was 36:9:19, as 
originally suggested by the closeness-of-fit test. 
A single dilute purple plant of F2, 2960-4, was tested in F; and found 
to give 38 dilute purple and 39 green plants. Of the eight possible geno- 
types for F, dilute purples, the only ones that could give only dilutelj 
purples and greens in F; are A Abb Pl PIUR’?’, Aabb Pl Plr'r’, and 
AabbPlIPIR’r. The first two should give a 3:1, and the third a 
9:7, F3 ratio. The plant had colored aleurone, which throws out of 
consideration the second genotype with rr. The F; plant-color ratio fits 
fairly well a 9:7 but not at all a 3:1 expectation, the observed numbers 
being 38:39 and the calculated numbers 43:34 and 58:19, with deviations] 
of 5 and 20, and probable errors of 2.6 and 2.9, respectively. The deviation 
from a 9:7 ratio might occur by chance once in five trials, P equaling 0.20, 
but that from a 3:1 ratio not more than twice in about a million trials, 
P equaling 0.000002. The genotype AabbPIPIR’r’ is thereforefl| 
decidedly favored by these results. The aleurone-color record shows that) 
this genotype is possible, since there were 57 colored and 56 colorlessi 
seeds, a relation about halfway between the 9:7 and the 27:37 ratiofj 
due to AaCCRr and AaC cRr, respectively. 
Intercrosses of F'2 color types 
It is realized that the tests of F2 types by studies of their behavior inf 
later generations as reported above, are markedly inadequate to servell 
