in plant height and possibly the increase in tillering 
(Table III), as also observed by Maguire (1956), may 
be effects only from a chromosomal unbalance, the com- 
bination of longer internodes in the rachis (measured as 
thicker kernels) with shorter ears bearing a lower num- 
ber of kernel rows would not result from just a general 
reduction of vigor. In the background of modern maize, 
long internodes in the rachis are associated with longer 
ears, even under conditions of stunting, but in primitive 
maize such as Confite Morocho of Peru (Grobman et ai, 
1961) and in the archaeological wild maize of Tehuacan, 
Mexico (Mangelsdorf et a/, 1946), relatively long inter- 
nodes in the rachis are associated with tiny eight-rowed 
ears. The data (Table II1) show that there was no over- 
lapping in the range of variation for ear length and almost 
none for kernel rows and kernel thickness. The one 10- 
rowed ear which occurred in the 21-chromosome plants 
was actually eight-rowed at the tip of the ear and, there- 
by, showing a tendency to be eight-rowed like the other 
ears bearing the extra chromosome. None of the 20- 
chromosome plants were eight-rowed. Thus, the Trip- 
Taste III. Phenotypic effects of the 7’. dactyloides counterpart for 
chromosome 2 when added to maize. ! 
Character 20-chrom 
21-chrom. 
4 Min. Max. = Min. Max. 
Plant height cm. 96.0 75.0 120.0 90.5 738.0 110.0 
No. of tillers 2.8 2.0 3.0 4.3 4.0 5.0 
Ear length cm. 14.2 13.5 17.0 10.5 Tel 12.0 
Kernel rows 11.5 10.0 12.0 8.1 8.0 10.0 
Kernel thickness mm.” 3.6 3.3 3.8 4,2 3.7 4.7 
1 Since the population is small (16 plants), maximum and minimum 
are given rather than standard deviations. 
? Averaged from 10 consecutive kernels in the central region of 
each ear. 
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