from South America in pre-Columbian times. Its South 
American progenitor was subsequently found in Colom- 
bia and identified by Roberts et al. (1957), as Cabuya, 
an eight-rowed race that is both tripsacoid and has nearly 
knobless chromosomes (average, 2.2 knobs). Grobman 
et al. (1961), suggested that these two features might 
result from indirect introgression, by way of Sabanero 
(1.5 knobs), from a South American species of T'ripsa- 
cum, T. australe, which, as shown by Graner and Ad- 
dison (1944), is unlike its knobby Central and North 
American relatives in having almost knobless chromo- 
somes. 
The blending of these three diverse germplasms from 
Chapalote, teosinte and Harinoso de Ocho produced, in 
Mexico and the American Southwest, new and more 
productive races of maize with increased adaptability 
sufficient to permit maize cultivation to spread north to 
northern Utah in the Great Basin. As this maize spread 
northward into the Dakotas in the Plains east of the 
Rocky Mountains and east across northern United States 
and on into New England, there was a filtering out of 
the eight-rowed element which became stabilized as the 
race called Northern Flint. Eventually, with the migra- 
tions of European farmers, these northern flints en- 
countered the southern dents which had spread north- 
ward from eastern Mexico. The resulting hybridizations 
yielded the world’s most productive race, our modern 
Corn Belt Dent, as shown by historical records (Wallace 
and Brown, 1956). The efficient use of these diverse 
germplasms which are now captured to various degrees 
in modern inbred lines of maize involves a knowledge of 
their origins and a recognition of their particular effects 
upon a spikelet-rachis relationship (Galinat, 19638). 
There has been some confusion surrounding the origin 
and identity of this important eight-rowed race. This 
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