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Nebraska Agricultural Exp. Station , Research Bui. 20 
produced by the particular combination of Mendelian factors in 
each hybrid. 
Tho perhaps possible, no elemental strain of corn has yet 
been found by the Nebraska Experiment Station, or to our 
knowledge has been reported elsewhere, which is as vigorous or 
productive as the original variety from which it was derived 
by repeated self-fertilization. On the other hand, a large range 
of degrees of productivity is found in first generation hybrids 
between various elemental strains, ranging from no increase to a 
somewhat greater productivity than that of the original variety. 
Our results and those of a number of other investigators would 
seem to justify more extended investigation of the practical pos- 
sibilities of wholesale elimination of undesirable Mendelian fac- 
tors and the recombination of those factors which result in 
superior production. Methods and results along this line at the 
Nebraska Experiment Station are as follows: 
Fm. 7. — Covering tassels and ear shoots with paper bags preparatory to 
artificial self-fertilization. This is normal Hogue's Yellow Dent 
corn which has never been self-fertilized and may be compared for 
size with corn of the same variety in figure 8 which has under- 
gone six years of inbreeding and is growing in the same field. Corn 
in both illustrations is full grown and at the same stage of develop- 
ment. 
