Feb. 23, 1924 
Teosinte Maize Hybrids 
59i 
Number or suckers.— While there are 15 significant correlations 
with number of suckers, all but four of these would be expected for both 
physiological and genetic reasons. Of the four which can be explained only 
on the basis of genetic relationship, the highest is with rank of the pistil¬ 
late inflorescence, and all involve some measure of the form of this in¬ 
florescence. These correlations indicate clearly a tendency for plants 
with few suckers to bear maizelike inflorescences. 
Diameter of culm.— Normal maize and teosinte differ pr6nouncedly 
in diameter of the culm, and this difference is greatly magnified when the 
maize parent is brachytic; yet, notwithstanding this fact, there are 
more disherences with diameter of culm in the brachytic-teosinte hy¬ 
brid than with any of the other characters studied. It seems clear that 
physiological factors are able to mask most of the genetic relationships 
which exist, though the negative correlation with alicole index indicates 
that the most maizelike pistillate inflorescences will occur on plants with 
the thickest culms. 
Leaves above upper branch. —With leaves above the upper branch, 
which is one of the best differentiating characters between maize and 
teosinte, there are no significant disherences. While the coefficients for 
none of the correlations with this character are high, with the exception 
of that with the leaves above the best inflorescence, the many negative 
coefficients where physiological and gentic factors are at work in opposite 
directions indicate the relative strength of the gentic relationships. 
Total number of leaves. —With the character, “total number of 
leaves,’ ’ there are two significant disherences, one of which can not be 
explained readily on the basis of the interaction of physiological factors; 
but in this case the coefficient of — o. 148 is but slightly in excess of three 
times the error, and with the number of coefficients under consideration 
several chance departures of this magnitude from complete independence 
are to be expected. Of the coherences, there are three clear examples 
of linkage, those with central spike index, length of the pistillate portion 
of the best spike, and rank of the pistillate inflorescence. 
Central spike index. —Relatively long central spikes are an out¬ 
standing characteristic of brachytic maize, but from the standpoint of 
correlations with other characters the index is unsatisfactory. While 
there are only two significant disherences there is a complete absence of 
clear genetic linkage. 
Branching space. —The length of the branching space also is un¬ 
satisfactory from the standpoint of correlations, since in many instances 
physiological and genetic factors operate in the same direction; and 
where disherences are found they obviously are due to the greater weight 
of the physiological factors. 
Length of central spike. —This character has many of the objec¬ 
tions of the other measures of the terminal panicle, though it should be 
observed that the negative correlations with days to pollen and silk, the 
former significant, show that linkage is involved with these complex 
characters. 
Number of tassel branches. —There is one clear genetic relation¬ 
ship with this character, that with the length of the pistillate portion of 
the best spike, though, curiously enough, this relationship is not sus¬ 
tained with the other measures of the pistillate inflorescence. 
Length of the longest tassel branch. —While there are several 
significant disherences with this character, all can be ascribed to the 
interaction of physiological factors. There is one clear genetic correla¬ 
tion evidenced in the negative coefficient of —0.309 with alicole index. 
