re 
ey of the maize cob (Galinat et al., 1956; Sehgal, 1963). 
The presence of a short, thick rachilla inclined to the 
axis, pronounced glume cushions, slightly upeurved 
glumes, comparatively soft rachis tissue, and well de- 
veloped central pith in the maize cobs of the fields sug- 
gests the introgression of segments of chromosome 9, 
and possibly chromosome 4, of teosinte. 
Might ears selected by the cultivator as seed ears from 
a field where maize X teosinte hybrids were known to be 
abundant were studied. These very productive ears were 
not highly tripsacoid, but they too showed evidence of 
teosinte introgression (rigid cob, straight rows, and in- 
durated glumes). Four of these ears were shelled and 
100 seeds from each ear were grown. Three cobs yielded 
all maize plants, but the fourth produced three maize X 
teosinte hybrids. This frequency of three maize X teosinte 
hybrids per 400 plants compares well with the number 
of maize X teosinte hybrids estimated to be present in the 
field and the abundance of highly tripsacoid cobs found 
in the total harvest. 
Maize Xteosinte hybrid seed on the predominantly 
maize-pollinated ear can not normally be distinguished 
morphologically from pure maize. Yet at Nobogame 
several ears from the same field were selected from the 
total pile because they possessed smaller than usual seeds. 
These small seeded ears uniformly yielded maize X teo- 
sinte hybrids when planted. It was found that if the ear 
is pollinated only by teosinte, the hybrid seeds are smaller 
than the few hybrid seeds found on a predominantly 
maize-pollinated ear. Thus there appears to be a chemi- 
cal feed-back mechanism (growth hormone/) between 
the developing seed and the cob. This postulated hor- 
mone might act to stimulate the conduction of food 
through the cob to the developing seed. 
Controlled pollinations of teosinte on the corn inbred 
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