Blando de Sonora, Pima-Papago and Fremont Dent are 
seen in Plate X XV). 
he denting of kernels in Pima-Papago to produce the 
Fremont Dent apparently allowed a more northerly ex- 
tension of the culture of this hybrid race. The dent type 
of kernel has some of the advantages of both the hard, 
flinty kernels which are more resistant to decay in cool 
moist soils and the soft, floury kernels which are easier 
to grind for flour. The dent itself refers to a depression 
which develops in the crown of the kernel and extends 
toward the column of soft starch which occurs in the cen- 
tral region of the kernel. The sides of dent kernels are 
flinty and, thereby, provide protection against decay in 
the region most susceptible. During germination, the 
column of soft starch expands toward the crown, causing 
the dent to disappear. 
The degree of denting is variable in different races of 
maize and appears to be one of the effects of teosinte in- 
trogression. Denting is correlated with the number of 
chromosome knobs, which in turn is related to tripsa- 
coidness in the maize from western Guatemala (Mangels- 
dorf and Cameron, 1942) and in the maize from the 
United States (Brown, 1949). Since there is at most only 
slight denting in Chapalote even where there is extensive 
teosinte introgression, it was apparently the introduction 
of Maiz de Ocho germplasm combined with the tripsacoid 
Chapalote germplasm that made denting possible. 
Although most collections of Fremont Dent appear 
to be merely a dented form of the Pima-Papago race, 
apparently some of its northernmost isolates have ac- 
quired slightly more pointed kernels and shorter ears than 
the Pima-Papago race and, consequently, have some 
superficial resemblance to the race called Zapalote Chico. 
In fact, it has been suggested that Zapalote Chico jumped 
about one thousand miles from central Mexico to the 
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