308 
Journal of Agricultural Research 
Vol.XXIX, No. 6 
The yellow seedlings were similar to 
the normal green seedlings in all 
respects except color. Those grown 
out-of-doors died after producing three 
or four leaves while the green plants 
grew normally without indication of 
chlorophyll disorders. Fifteen of these 
surviving green plants together with 18 
of the plants having the green section 
of the chimera as a male parent were 
self-pollinated. 
From these self-pollinated ears 4,489 
seedlings were grown in the green¬ 
house, all being normal with no recur¬ 
rence of the yellow character. In. 
addition, the progeny of self-pollinated 
normal sibs of the chimera resulted in 
547 plants all normal with respect to 
chlorophyll disorders. 
Although these greenhouse seedlings 
were normal with respect to the yellow 
coloration they exhibited another type 
of chlorophyll disorder. This latter 
form, in extreme cases, resembled 
ordinary albinism but with impercep¬ 
tible gradation from pure white to 
normal green. There was much vari¬ 
ability between the progenies of dif¬ 
ferent ears in this respect, some having 
100 per cent of the plants affected, 
while in others less than 10 per cent 
showed the character to a noticeable 
degree. Except in the most extreme 
cases the plants recovered after the 
first four or five leaves developed and 
then remained normal. 
It was thought at first that this 
second deficiency was related to the 
dominant, yellow disorder indicating a 
general breakdown of chlorophyll, but 
subsequently unrelated progenies grown 
under the same conditions exhibited 
the phenomenon. Remnants of the 
ears planted in the field showed no 
evidence of this albinistic character, 
and it now seems probable that this 
character depends for its expression on 
some of the peculiar environmental fac¬ 
tors of greenhouse culture. 
At the time the seedlings were grown 
in the greenhouse the remainder of the 
Fi hybrid seeds having the yellow sec¬ 
tion of the chimera as the male parent 
were planted, giving 12 green and 16 
yellow seedlings. Contrary to their 
behavior in the field, the yellow seed¬ 
lings raised in the greenhouse grew 
slowly and finally flowered, and al¬ 
though no seeds were produced, a small 
amount of pollen was shed. The 
growth of these seedlings had been so 
slow, however, that all the normal 
plants had matured long before the 
yellow plants flowered and only plants 
of the annual teosinte (Euchlaena 
mexicana ) were available for crossing. 
Several crosses were made between 
yellow plants and this teosinte but 
only 40 seeds resulted. Of these 10 
seedlings are now growing, 6 being 
yellow and 4 green. From this be¬ 
havior it seems clear that the yellow 
half of the chimera was the result of a 
dominant mutation from green to yel¬ 
low in one chromosome at a very early 
somatic cell division since it affected 
almost exactly one-half of the plant as 
well as the germ plasm. 
Since plants lacking chlorophyll can 
not survive, the production of a further 
generation of this mutation was made 
possible only by the fortuitous circum¬ 
stance that it involved but one-half of 
the plant. Had it occurred at an 
earlier cell division or previous to fer¬ 
tilization, the result would have been a 
single self-yellow seedling which would 
have perished without progeny. 
As none of the yellow seedlings in the 
subsequent generation survived in the 
field, and as these were the only plants 
carrying this dominant mutation the 
character would have been automat¬ 
ically eliminated, precluding further 
study. It is believed that this is the 
only dominant mutation observed in 
maize within historic times and it fur¬ 
nishes evidence why such mutations 
have not been observed more fre¬ 
quently. 
The" fact that the chlorophyll de¬ 
ficiency observed in this case proved 
heritable raises the question as to 
whether similar deficiencies observed 
in Japonica plants would not also 
prove to be heritable if the pollen 
could be collected from the white areas. 
There can be no question that on ex¬ 
treme Japonica plants the albino 
stripes often involve entire spikelets of 
the staminate inflorescence, an excel¬ 
lent illustration having been afforded in 
the case of a Japonica plant which pro¬ 
duced an apogamous terminal panicle 
where each spikelet developed into a 
minature plant. Some of these minature 
plants were perfect albinos, others 
variegated, and still others, self-green. 
With the exception of the albinos, such 
plants can be propagated and it seems 
not unreasonable to infer that normal 
self-green plants could be produced 
from the recessive Japonica type by 
such means. The occurrence of albino 
plantlets strongly suggests that had 
these spikelets developed normally they 
would have produced pollen genetically 
albinistic and the occurrence of albino 
seedlings in the progeny of many com¬ 
mercial strains of Japonica may be due 
to this phenomenon. 
