32 
Research Bulletin A 7 o. 2 
covered by the data from nine ears that were selfed artificially. 
The interesting part of the record is decidedly the F 3 families, 
for they arose from three ears, each having a different number of 
rows. The 8-rowed mother gave progeny with a few more 10 
rowed ears than 8-rowed ears, but one can see what a tendency 
there is toward the 8-rowed condition. It would probably be very 
easy to recover a typical 8-rowed race in the next generation. 
On the other hand, the progeny of the 14-rowed mother is a 
variable family with the modal condition at 14 rows. The 
number of ears exceeding this condition is sufficient to lead one 
to believe that a race like the No. 8 parent would be as easy to 
obtain as the one like the No. 15 parent. But this could not be 
done, we believe, by selecting ears having the flint condition 
There is certainly some sort of a correlation between the dent 
condition and a high number of rows, for all of the ears with 
a high number of rows are dent in character. 
This dent, No. 8, was also crossed (Table 8) with an 8-rowed 
sweet, No. 54 (Black Mexican). Nine F g families were grown 
in this cross, and strains exactly like each parental condition 
were recovwed. The progeny of (8x54)1-13 are as typically 8- 
rowed as the Black Mexican variety, while the progeny of No. 
(8x54)1-5 and No. (8x54)1-6 are practically like No. 8, in 
number of rows, tho they both differ in other characters. 
Tables 9, 10, and 11 are similar to Table 8. Different in- 
dividuals belonging to the commercial varieties known as Tom 
Thumb and Black Mexican were crossed. This gives one some 
idea of the various gametic possibilities within what might be 
considered single races. No. 54 is a comparatively pure 8-rowed 
race, but No. 60, since it produces individuals having from 8 
to 16 rows, may be expected to have various potentialities. 
Table 9 lists the data from the cross known as 60-3x54. The 
F-l generation is very variable, if confidence can be placed in a 
population of only 33 ears. Three F 2 families were grown. 
Family (60-3x54) -1 grew from a 16-rowed ear, and shows clearly 
that it had within it possibilities different from those of ears 
(60-3x54) -5 and (60-3x54) -6, the other two ears that produced 
F 2 families. In fact, tho ear (60-3x54) -1 produced no daughter 
ears with less than 12 rows, ear (60-3x54) -6 produced no 
daughter ears with more than 12 rows. No further proof is 
necessary to show that one of the parental plants was hetero- 
zygous for certain of the factors necessary for the production of 
rows greater than eight in number. The F 1 individuals, in other 
words, Avere different in gametic constitution. 
Even the family ( 60-3x54) -1 contained individuals hetero- 
zygous for several factors, moreover, tho apparently it was some- 
what low in variability. This is shown by the varied appearance 
