CHARACTERS IX AX UPLAND-EGYPTIAN COTTON HYBRID. 33 
cotton, stated to have been Gossypium peruvianum, with a fuzzy-seeded American 
upland variety, reported (p. 5) dominance of the smooth-seeded condition, and stated 
(p. 19) that the same relation obtained in crossing two nearly related Indian cottons 
which had, respectively, smooth and fuzzy seeds. In subsequent generations of the 
latter hybrid some of the naked-seeded parents bred true, others segregated irregularly, 
while most of the fuzzy-seeded parents gave only fuzzy seeds in their progenies. 
Fyson (20, p. 26) notes, however, that there was variation in the degree of fuzziness, 
and it is doubtful that the inheritance was of a simple type. 
Balls (S, p. 21), in a hybrid between an entirely fuzzy-seeded upland cotton and 
an Egyptian variety which had only a little fuzz on the seeds, found that F, was 
entirely fuzzy like the upland parent and that the F 2 population comprised 147 
plants that were entirely fuzzy seeded and 8 plants resembling the Egyptian parent. 
Apparently both the uplandlike and the Egyptianlike F 2 plants bred true or very 
nearly so in F 3 . Similar data are presented in a later publication (4, pp. 71-74 ) and 
are interpreted as pointing to a dihybrid ratio (15 to 1), although the evidence is not 
conclusive. In crosses between two Egyptian varieties differing in the amount of 
fuzz on the seed, Balls (6, p. 143) reported that "in all cases they have given a sim- 
ple 3 to 1 ratio, more fuzz being dominant over less fuzz and expectation has been 
fulfilled in F 3 ." 24 
McLendon (84, pp. 220-225) reported that in his hybrids of the smooth-seeded 
sea-island cotton with fuzzy-seeded upland varieties, fuzziness was dominant. His 
F 2 populations, classified simply as fuzzy and smooth, show great diversity in the 
proportions of the two classes and afford little evidence of definite segregation. 
IN CHARACTERS NOT GIVING DEFINITE MENDELIAN RATIOS IN F 2 . 
It has been shown that the second generation of the Holdon-Pima 
hybrid afforded no satisfactory proof of segregation in definite ratios 
except possibly in the characters petal spot, anther color, and mid- 
lock furrow index. It remains to consider whether the third genera- 
tion yielded evidence that segregation of a less definite type had taken 
place in F 2 in regard to other characters. Eighteen of the characters 
which were determined on the parental and F 2 progenies in 1919 were 
also determined on 22 F 3 progenies grown in 1920. One of these 
characters, petal spot, gave evidence of definite Mendelian segregation 
and has been considered in that connection. The other 17 characters 
gave unimodal frequency distributions in F 2 . The size of the F 3 
progenies varied from 8 to 46 individuals, but it was not possible to 
determine all of the characters on every plant of each progeny. No 
character was determined in any progeny on less than seven 
individuals. 
Evidence of segregation in F 2 was sought by comparing for each 
character (1) the means of the several F 3 progenies as to the signifi- 
cance of their differences, (2) the means of the F a progenies with the 
values given by their respective F 2 parents, and (3) the coefficients 
of variation of the F 3 progenies with those of the parental and F., 
populations. 
COMPARISON OF THE Fj PROGENY MEANS. 
Table 8 shows for all characters determined in F 3 25 the moans of 
the F 3 progenies which gave, respectively, the highest and the lowest 
mean, and the means of the populations representing the parent vari- 
eties which were grown in the preceding year. 
"This simple type of Mendelian Inheritance was not encountered by the writer In crosses bet wee 
varieties of the Egyptian type of cotton (Pima ami Gila) which differed rat Iter markedly m the degree 
of fuzziness of the seed coat. Six grades, including the parental extremes, were distinguished in Fj, and 
the frequency curve for that generation was unimodal and very nearly symmetrical. The indication, 
therefore, was that more than two factors were concerned. 
** Including, for the sake of completeness, the character petal spot, which is not further considered in 
this connection. 
