300 
Journal of Agricultural Research 
Vol. XXV, No. 7 
recessive combination. While two-thirds or n of the 16 would be 
expected to produce dwarf plants if the brachytic and dwarf characters 
are independent, the departure of 3 from this expectation may be 
ascribed to chance. Curiously, the percentage of germination was 
slightly higher in the segregating progenies than in the others, but not 
significantly so. The percentage of dwarf plants in the 8 progenies was 
very close to the expected, though 2 were very low. It is interesting to 
observe that the percentage of germination on the 3 progenies which 
were below the expected in the percentage of dwarf plants is 13.8 ±2.1 
lower than the progenies which equaled or exceeded the expected per¬ 
centage of dwarfs. The classification of plants is shown in Table II. 
Table II .—Showing F z results obtained from growing self-pollinated seed of the brachytic 
plants which reappeared in the F 2 of dwarf-brachytic; the dwarf plants obtained represent 
the combination of the two characters , dwarf and brachytic; the counts are made of seed¬ 
lings raised in greenhouse flats 
PROGENIES SEGREGATING FOR DWARF 
Progeny. 
Number of — 
Percentage of— 
Seeds 
planted. 
Non¬ 
dwarf. 
Dwarf 
seedlings. 
Germi¬ 
nated 
seeds. 
Germi¬ 
nation. 
Dwarf 
seedlings. 
108 
49 
2 9 
78 
72. 0 
37 - 2 ± 3 - 7 
100 
73 
2 7 
100 
100. 0 
27. o±3. 0 
3 . 
106 
62 
19 
81 
76. 5 
2 3 - 4 ± 3 - 2 
4 . 
100 
6 S 
3i 
96 
96. 0 
3 2 - 3 ± 3 - 2 
5 . 
US 
5 2 
18 
70 
60. 9 
2 5 - 7 ± 3 - S 
6. 
100 
65 
9 
74 
74.0 
12. I±2. 5 
7 . 
100 
5 2 
4 
56 
56. 0 
7 - 1± 2 -3 
8. 
100 
60 
2 9 
89 
89. 0 
32. 6±3. 4 
Total. 
829 
478 
166 
644 
77*7 
25. 8±i. 2 
PROGENIES NOT SEGREGATING FOR DWARF 
1 . 
2 . 
3 . 
4 . 
5 . 
6 . 
7 . 
8 . 
Total 
108 
80 
117 
115 
102 
ii 5 
100 
102 
96 
48 
no 
93 
93 
90 
10 
99 
96 
48 
no 
93 
93 
90 
10 
99 
89. 0 
60. 0 
94.0 
81. 0 
91. 0 
78. 0 
10. 0 
97.0 
839 
639 
. 
639 
76. 2 
The inclusion of the double recessive class in the group of dwarf 
stature should have been reflected in the ratio of dwarfs to the other 
groups in the F 2 populations, the expectation then being nine normal, 
three brachytic, and four dwarf, but it is reasonable to suppose that the 
relatively high death rate for dwarf plants in field cultures so reduced 
the percentage of this type that the small increment due to the addition 
of the double recessive combination did not fully compensate for the 
loss due to low viability. 
