Aug. 18,1923 
Inheritance of Dwarfing in Maize 
319 
The percentage of liguleless plants is 24.7 ±1.02, of perfect flowered 
ears 20.8±0.97, and Q (Yule's coefficient of association) =0.167. The 
expected distribution on the assumption of a 9:313:1 grouping would 
be 455.1 : 151.7 : 151.7 : 50.5, from which the observed departs by an 
amount which could be expected as the result of chance about 4 times 
in 10, (x 2 ==2.94). 
The fact that all but two of the dwarf plants had staminate ear spikes, 
and the possibility that the absence of such spikes in these two cases may 
be due to the activities of the ear worm, necessitates the conclusion that 
this character and dwarf stature are very closely linked. It necessarily 
follows that the linkage relations of the staminate ear spike character 
in question will be identical with those of dwarf stature. But by 
confining the analysis of staminate ear spikes to plants of nondwarf 
stature, it becomes possible to measure the linkage relations of a single 
factor for the other heterozygous staminate ear-spike character involved 
in this cross. 
This factor is the one not linked with brachytic stature. Confining 
the analysis to those plants of normal stature only, the fourfold grouping 
with liguleless leaves becomes: 
Normal leaves. 
Liguleless leaves. 
Total. 
Without 
d* spikes. 
With 
<? spikes. 
Without 
c? spikes. 
With 
& spikes. 
395 
140 
109 
33 
677 
The percentage of plants with staminate ear spikes is 25.6± 1.13 and 
for liguleless leaves 2i.o±i.o5, while Q = o.o79±o.o7, or practically 
50 per cent, of crossing over. 
It may be concluded, therefore, that the gene for liguleless leaves is 
independent of this factor for staminate ear spikes, as well as of the 
corresponding factor which is linked with dwarf. 
INHERITANCE OF PERICARP COLOR 
The inheritance of pericarp color in this hybrid presents no new or 
unexpected features. The association of brachytic stature with color¬ 
less pericarp confirms previous results where these characters were 
found to lie from 31 to 43 units apart. The coefficient of association is 
found to be 0.389 ±0.076, which for the 13 to 3 grouping is the equivalent 
of 38 per cent±2.3 crossovers. 
SUMMARY 
(1) There are two forms of dwarf maize in which the reduction in 
height is due to shortened internodes and not to a reduction in the number 
of internodes. One of these is known as dwarf, the other as brachytic. 
The variation known as dwarf also departs from the normal in characters 
other than stature. The most striking of these other changes are the 
shortened and widened leaves, the reduced number of tassel branches, 
and the perfect flowered ears. 
(2) When the dwarf and brachytic variations are crossed, the plants of 
the first generation are fully as tall as normal plants from which the 
