PLANT Coors IN MatIzE 45 
trials. One of the F, brown plants that, when selfed, gave a 3:1 ratio 
in F;, when crossed with green gave 34 brown and 41 green plants where 
equal numbers were expected, the deviation being 3.5 + 2.9. None of 
the fourteen F, brown plants bred true in F;. The fourteen plants should 
theoretically have given F; ratios of 1:0, 3:1, and 9:7 in approximately 
the respective numbers of 1.6, 6.2, 6.2, while the observed numbers were 
0, 9, 5. Such deviations might occur by chance once in five trials, P 
equaling 0.22. 
It is often difficult and sometimes practically impossible from ordinary 
F; progenies to distinguish between the: two genotypes of brown which 
throw 3:1 progenies, namely, aa BB PlplandaaBb PI Pl. The green 
plants thrown by the former often show some brown pigment in the exposed 
parts of the sheaths and husks (type Vla), a condition not seen in the 
greens (VIb) thrown by the latter. In some lots the brown pigment 
is fairly conspicuous but in others it is very weak or is absent. Again, the 
greens of type VIb thrown by browns of the genotype aaBb Pl Pl 
show considerable brown in the glumes of the staminate flowers. This 
is particularly pronounced when r (a gene for cherry pericarp which is 
effective only in the presence of PI) is present, but when this factor is 
lacking the brown color is often so faint that it is impossible to distinguish 
between a green plant carrying Pl and one lacking it. If r-’ is present, 
the green plants carrying Pl develop a light brownish pericarp at maturity 
while those lacking Pl never show this pericarp color whether or not B 
is present. Here again, however, the lght brownish pericarp due to 
rk, Pl, and aa may be wholly masked if there happens to be present 
another pericarp color gene, P, which with aa brings about a strong 
brown color of the pericarp whether or not Pl or B is present. On the 
whole, therefore, it is difficult, and often impossible, to determine the 
genotype to which a brown plant belongs, by an inspection of the green 
plants occurring in its progeny. Because of this, the 3:1 lots of F; 
progenies of F, brown plants are lumped together in group 2 of table 13 
without any attempt to separate them into the two classes expected. 
Fortunately, it is readily possible to distinguish between brown plants of 
the two genotypes under consideration here by means of appropriate 
crosses. 
4 An account of these pericarp-color factors is to be published later by Dr. E. G. Anderson, who is 
making a study of the pericarp colors of maize. 
