28 BULLETIN 1164, U. S. DEPARTMENT OF AGRICULTURE. 
deeply and narrowly lobed leaf, with G. arboreum or G. negleclum, species which 
have broader and shallower lobes, the F! is exactly intermediate. In a later paper 
(SI, pp. 225-230, Table 14) similar results in F, and a close approximation to a 1:2:1 
ratio in F 2 are reported. There was a high parent-offspring correlation between F 2 
and F 3 . Furthermore, F 2 individuals which had a leaf factor closely approaching 
that of one or the other parent gave strong evidence of homozygosity in their F 3 
progenies while progenies of intermediate F 2 plants showed segregation similar to 
that of the F 2 population. 
Fyson (20, pp. 11-15) crossed two distinct species grown in India, one having 
broadly and shallowly lobed leaves, the other deeply and narrowly lobed leaves, and 
obtained only the latter type in Fj. The distribution in F 2 was not recorded, but of 
13 F 3 progenies 5 showed only the deeply and narrowly lobed type, 4 progenies 
showed practically only the broadly and shallowly lobed type (84 in a total of 85 
individuals), and 4 progenies, when combined as one array, gave a 3 to 1 ratio with 
the deeply and narrowly lobed type predominating. Similar behavior continued in 
the fourth and fifth generations, some of the dominant type breeding true and others 
segregating in approximately a monohybrid ratio, while the recessive type (broadly 
and shallowly lobed) bred true with a few exceptions, which the author attributes 
to accidental cross-pollination. 
Shoemaker (36), crossing two upland cottons, one being an "okra leaf" (deeply 
and narrowly lobed) type segregated from the King variety and the other being the 
Edson variety with relatively shallow and broad lobes, obtained an intermediate F x 
and close approximations to a 1:2:1 ratio in F 2 and in the F 3 progenies of inter- 
mediate F 2 individuals. His results, although based upon grading rather than 
measurement, accord therefore with those ot Leake. 
McLendon (34. pp. 169-185), crossing narrowly lobed types (" okra leaf," sea 
island) with broad-lobed varieties of upland cotton and making his classifications by 
inspection rather than by measurement, obtained results similar to those of Leake 
and Shoemaker. 
Balls (6, p. 158) used the same expression for depth of lobation as the writer's 
leaf lobe index and obtained results with an upland-Egyptian hybrid similar to those 
here described for the Holdon-Pima cross, the Egyptian (deeply lobed type) being 
dominant in Fj and no segregation in a definite ratio being discernible in F 2 . 
LEAF BLADE COLOR. 
The character leaf blade color, as was explained on a preceding page, could not 
be graded satisfactorily in the Holdon-Pima hybrid, the difference between the 
parent varieties being only that between a lighter and a darker shade of green. 
Other investigators have studied hybrids of which one of the parents had red color 
in the foliage, and their results may be considered briefly. 
Leake (31, pp. 214-215, Table 6, p. 246) found in various crosses involving a red- 
leafed and a green-leafed type that the red color was dominant but with diminished 
intensity in F, and that very close approximations to a monohybrid ratio for presence 
of the red color as contrasted with its absence were obtained in most of the F 2 
progenies. There was. however, wide variation in the intensity of the red color in 
different F., individuals in which red was present. The behavior, therefore, was 
similar to that of the character petal spot in the Holdon-Pima hybrid. 
McLendon (34, pp. 169-178), in crosses of the Willetts Red Leaf variety of upland 
cotton with upland varieties having green leaves, concluded that F t was intermediate 
and that the segregation in F 2 indicated a 1:2:1 ratio. F 3 progenies from red-leafed 
and from green-leafed F 2 individuals appeared to be homozygous, while in progenies 
of intermediate F 2 individuals the three types segregated, but usually not in very 
close approximation to the 1:2:1 ratio. In crossing a broad-lobed, red-leafed type 
(Willetts) with a narrow-lobed, green-leafed type ("okra leaf") he obtained an 
intermediate expression of both characters in Fj and recovered in F 2 the nine types, 
in approximately the proportions to be expected when both characters give a mono- 
hybrid ratio and the heterozygotes can be distinguished. 
LEAF CALLUS COLOR. 
In the Holdon-Pima hybrid the F x and F 2 means were approximately intermediate 
although nearer that of the Holdon parent, and there was no indication of a pluri- 
modal frequency distribution in the second generation. (Fig. 14.) 
Balls (4, p. 24), studying this character in upland-Egyptian crosses, found an 
intermediate condition in F x . Classifying an F 2 population as "spotted," "inter- 
mediate, ' ' and ' ' no spot ' ' he obtained a close approximation to a 1 : 2 : 1 ratio. Three 
F 3 progenies of intermediate F 2 plants also gave close approximations to this ratio. 
In a later publication (6, p. 133) Balls states that "extracted full spot and spotless 
breed true, without known exceptions." 
