568 
Journal of Agricultural Research 
Vol. XI, No. n 
18 days from silking. Correlations involving days to harvest and matur¬ 
ity therefore have relatively little significance. The data are sufficient, 
however, to prove that differences in the rapidity of maturing could not 
have been an important factor in causing the differences in damage. 
In no instance was there a significant interprogeny difference in the 
average maturity at 16, 17, or 18 days from silking. Neither did the 
two Hopi hybrids, the table variety of soft corn, and the commercial 
variety of sweet corn, differ significantly in this respect from the worm- 
proof progenies. The interprogeny regression of the degree of maturity 
on days from silking to harvest, of 0.72, indicates that for each additional 
day that elapses the maturity advances on the average 0.7 of a grade. 
Since it is almost certain that the regression of maturity on days is not 
linear, the average difference in maturity between the ears harvested 
at 16 and at 17 days from silking is perhaps a better criterion of the 
regressions than that calculated from the correlation coefficients. This 
difference is 1.3 grades of maturity. 
It might have been expected that the progenies requiring the longer 
season to reach the silking stage would also have required a longer time 
after silking before reaching the edible condition. This proved not to 
be the case. The correlation between the degree of maturity and days 
to silking was positive and close, 0.924. This was to a slight extent 
due to the fact that silking to harvest averaged slightly longer in the 
late season progenies, but with silking to harvest constant the partial 
correlation of maturity and days to silking was 0.88. As a further check 
on this determination the ratio of “maturity” to “silking to harvest” 
was correlated with days to silking and found to be 0.73. 
Two possible explanations are suggested for this unexpected relation: 
(1) The field varieties used as parents in the crosses were longer 
season than the sweet varieties, and field varieties are supposed to 
mature the seed more rapidly after fertilization. If there was coherence 
between these two characteristics, the later maturing parents should 
mature their seeds more rapidly. It should be recalled, however, that 
with the same number of days from silking to harvest the writers failed 
to detect significant difference in the degree of maturity among the 
different progenies or the nonsweet varieties included in the experiments. 
(2) The climatic conditions following the flowering of the later prog¬ 
enies may have been more conducive to rapid maturing of the seeds 
than earlier in the season. It is difficult to find support for this view 
in the meteorological conditions of the latter part of the season when the 
days are shorter and the temperatures no higher. It has often been 
observed, however, that varieties planted late in.the season mature 
with greater rapidity than the meteorological conditions seem to warrant. 
