July i, 1925 Productiveness and Deleterious Characters in Corn 
99 
Selection for large ears frequently has resulted in ears with larger 
numbers of kernel rows, and it seems probable that the benefits 
accruing from increased size of ear may nave been nullified for the 
reasons already noted. The diameter of ear and the number of rows 
of kernels are correlated, though how much of this relation is un¬ 
avoidable is unknown. Size of ear is dependent upon length as well 
as diameter, however, and the number of kernel rows need not be 
increased in obtaining longer ears. It therefore seems that selection 
on the basis of total length of ear (or ears) per plant, together with 
as much diameter as may be had without too many rows of kernels, 
may be recommended as satisfying the size requirements without in¬ 
creasing the ill effects that apparently are associated with a larger 
number of kernel rows. It is probable that the maximum length 
of total ear per plant can be obtained by having more than one ear 
on a plant. Whether this is necessary to obtain the maximum yield, 
however, or whether plants bearing one long ear may be equally 
productive under some conditions, remains to be determined. 
SUMMARY 
Experiments are reported in which prolific varieties were more 
productive as a class than comparable nonprolific varieties. The 
ears in the prolific varieties had fewer rows of kernels and smaller 
diameters and the kernels were less angular than in the nonprolific 
varieties. 
In comparisons between groups of ears, both within prolific and 
nonprolific varieties, and within several F! crosses, those with fewer 
kernel rows, larger kernels, or less angular kernels were more pro¬ 
ductive. In the comparisons, both between and within varieties, the 
lots with fewer kernel rows produced fewer barren plants and, in 
some cases, made the larger total yield in spite of a smaller yield 
per bearing plant as measured by the yield index. 
Selection for different numbers of kernel rows in selfed lines re¬ 
sulted in an essentially steady increase during five generations in 
the degree of conformity to the parental number. The rate of this 
increase was greatest in the lines with the fewest rows and decreased 
as the number of rows increased. Selection also resulted incidentally 
in other differences. Thus, the lines having smaller numbers of 
kernel rows had a greater length of ear per plant, ears with a smaller 
diameter, and kernels more rounded and with less indentation than 
the lines having larger numbers of kernel rows. Finally, the fewer- 
rowed lines were more resistant to corn smut, had fewer plants with 
heritable deleterious characters, and were more vigorous and pro¬ 
ductive in general. 
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