CHARACTERS IX AN UPLAND-EGYPTIAN COTTON HYBRID. 
The fact is rather remarkable, considering the high parent-offspring 
correlations in other characters, that no correlation was found to exist 
between the number of bolls borne by the F 2 parent and the average 
number per plant in the corresponding F 3 progeny, the value of r 
having been 0.095 = 0.143. One of the most fruitful of the F 2 parents, 
the one which gave the largest F 3 progeny, produced offspring of 
which 23^ per cent were completely or almost completely sterile, only 
1 of the 21 other F 3 progenies having shown a higher percentage. 31 
Of the 22 F 3 progenies. 9 contained from 3 to 38 per cent of com- 
pletely sterile individuals which matured no seeds, and most of these 
progenies contained also a certain percentage of plants which matured 
only a very few (not more than 5) bolls. In 4 progenies from 6 to 
10 per cent of the plants were nearly sterile, but none was completely 
so. In the remaining 9 progenies none of the plants was recorded 
as sterile or nearly so. 
It is of interest to consider whether there was any relation between 
the relative sterility of these F 3 progenies and the relative variability 
of their morphological characters. The correlations were determined 
between the coefficients of variation or standard deviations for the 
IS characters measured or graded on these populations (see Table S 
and the percentages of sterile or nearly sterile individuals. Positive 
and presumably significant correlations were found in the following 
cases: 
Axis internode length r = 0. 545 ±0. 101 
Fruiting branch length r = . 513 — . 
Fruiting branch, first internode length r = . 854± . 040 
Leafleneth r= .379± .123 
Positive correlations also occurred between the relative sterility and 
the variability in respect to callus color and petal spot, but the coeffi- 
cients of correlation in these cases were only 2.6 and 2.3 times the 
respective probable error. The four length characters, high vari- 
ability in respect to which proved to be associated with a marked 
tendency to sterility, are all intercorrelated, doubtless physiologically. 
Especially notev orthy is the very high positive correlation in the 
case of the length of the first internode of the fruit ins: branch, the 
character which showed the greatest range in variability among the 
several F 3 progenies. It is fairly obvious that the presence of factors 
making for sterility might affect injuriously the development of the 
fruiting branch as a whole and hence might increase the variability 
of this organ, but it is not apparent why variability in the first inter- 
node of the branch should be so much more closely correlated with 
a tendency to sterility. At any rate, the conclusion may be drawn 
that variability in the length of the internodes, branches, and leaves. 
characters which might be expected to respond most readily to the 
influence of unfavorable growth factors, is more closely associated 
with a tendency to sterility than is the variability in color characters. 
hairiness, and size and shape of the bolls. 32 
21 On the F: plant referred to (No. 40), 2S0 bolls of all sizes were counted on October 15 as compared 
with a maximum of 405 and an average of 167 bolls per plant in the entire F: population. This individ- 
ual was the tallest of the 215 plants in the F : population and was characterized by numerous, nearly 
erect vegetative branches. The Fj progeny was remarkably uniform and closely resembled the parent 
individual except in the marked tendency to sterility and to a disc..- liage. 
32 Kottur (29) found that in a hybrid "between Oossypium hcrbaceum and G. ed the 
same kinds and degree of sterility as the parent species' and Fi and Fi a greater amount, li 
form of complete sterility accompanied by vegetative peculiarities (abnormal leaf col seen in 
the parents nor in Fi bu bout 7 per cent of the Fj individuals and from Q 
the individuals in differ. : ules. 
