Aug. 18, 1923 
Inheritance 0} Dwarfing in Maize 
3i3 
combination of characters, as is the case with anther ear and dwarf or 
dwarf and brachytic, the question of a common cause can hardly be 
avoided. From the mode of inheritance of these characters there can 
be no doubt that independent genetic changes have taken place on sepa¬ 
rate chromosomes. That such strikingly similar somatic resemblances 
can arise as the result of the alteration of unrelated and wholly separate 
hereditary elements appears incredible. It seems more probable that in 
maize some or all of the 10 chromosomes are practically identical, each 
with hereditary elements for all the characters of the complete plant as 
suggested by Emerson ( 3 ). Such a hypothesis permits the prediction 
that all characters in maize eventually will be found to involve at least 
10 independent factors and that these factors in a general way will have 
similar linkage relations. 
Thus the shortened internodes of dwarf and brachytic are genetically 
distinct, and both are associated with the development of staminate 
ear spikes. These spikes, like the shortened internodes, though bearing 
a close resemblance to each other, are wholly distinct from a genetic 
standpoint. Even more striking, of course, is the character complex of 
anther ear and dwarf. It seems not unreasonable that a change of 
whatever form in a similar group of genes in separate chromosomes 
would result in a somewhat similar somatic behavior. Such a hypoth¬ 
esis is in accord with the fact that most linked groups involve diverse 
organs and that the factors or hereditary elements for multiple factor 
characters are not found in one chromosome but are distributed through 
many. 
If other organisms possess identical chromosomes, then those organisms 
with few chromosomes should have relatively simple characters, speaking 
in a genetic sense, while those with many chromosomes should have 
complex characters composed of many factors. If mutations occur at 
the same rate in organisms with few chromosomes, as in those with 
many, then those organisms with few chromosomes should have many 
multiple allelomorphs while those with many chromosomes should have 
multiple factor characters. 
PERFECT FEOWERED EARS 
Perfect flowered ears always have been found associated with the 
dwarf stature in its numerous appearances. The character is of more 
than usual interest since it represents a reversion toward a more primitive 
form of maize, comparable in some respects to the ramose and tunicate 
forms. Perfect flowered ears are not limited to dwarf plants, and many 
maize breeders have encountered them on plants otherwise quite normal. 
In the writer’s experience the character is ephemeral, repeated inbreeding 
failing to stabilize its appearance in stocks of normal stature; and since, 
strictly speaking, it is the development of vestigial floral organs, it may 
well be that environment, especially photoperiodism, which is recognized 
as having a profound influence on the development of sex organs, is an 
important factor in its expression. 
In the present hybrid, 22.95 ±0.98 P er cent °f bh e plants were found 
to have perfect flowered ears. This seems fairly close to the expected 
25 per cent and it may be accepted as* a simple Mendelian character. 
When the three classes of plants—normal, brachytic, and dwarf—are 
examined with respect to this character, it is found that of the normal 
plants only 0.6 ±0.2 2 per cent have perfect flowered ears, while of the 
