Dec, 10, 1917 
Flaxwilt 
595 
of 1 to 2.27. This ratio is fairly close to the expectation. The number 
of susceptible plants ran rather high, although this was to be expected, 
since the E 2 plants were grown under slightly abnormal conditions, as we 
have already seen. Some of these plants showed only slight signs of 
infection and would no doubt have resisted entirely had they been under 
less severe conditions. In this case the discrepancy is in the direction 
expected, the number of susceptible plants running high. Since this is 
the only cross that gave definite ratios, too much emphasis should not be 
placed on these results until further experimental evidence is obtained. 
It is furthermore very desirable that experiments of this kind be con¬ 
ducted in environmental conditions which are kept fairly constant. 
Table IV .—Resistance to flaxwilt obtained with reciprocal crosses of resistant flax No. 4 
with susceptible No. 3 and their controls 
Parent strain. 
Date of 
planting. 
4E1 (F,). 
i 9 * 5 - 
Oct. 15 
...do. 
6E1. 
4E1 (self). 
. ^do. 
6E1 (self). 
.,.do. 
F 2 generation (6E1 9 and4Ei S ): 
6E1-1. 
1916. 
June 27 
.. .do. 
6E1-2. 
6E1—3. 
...do. 
6 El -4 . 
., .do. 
6E1- 1 ;. 
... do. 
6El-6. 
... do..... 
Total. 
Controls, F 2 generation: 
Resistant No. 4. 
.. .do. 
Susceptible No. 6. 
Susceptible No. 3. 
...do. 
...do. 
F 2 generation (4E1 9 , 6E1 d ): 
4 El“I. 
.. .do. 
4 El -2 . 
...do. 
4E1-3. 
...do. 
4 Ei —4 . 
...do. 
...do. 
4EI-6. 
.. .do. 
Total.... 
Num¬ 
ber of 
plants 
grown. 
Ratio at end of 
three weeks. 
Ratio at end of 
experiment. 
Num¬ 
ber of 
plants 
killed 
by 
wilt. 
Wilted. 
Not 
wilted. 
Wilted. 
Resist¬ 
ant. 
9 
2 
7 
9 
O 
9 
9 
I 
8 
9 
0 
9 
17 
O 
17 
0 
17 
0 
17 
13 
4 
17 
0 
17 
76 
56 
20 
67 
9 
57 
133 
IOO 
33 
128 
5 
US 
125 
56 
79 
123 
2 
118 
104 
49 
55 
101 
3 
97 
66 
22 
44 
66 
0 
65 
34 
19 
34 
0 
33 
■538 
298 
240 
5 i 9 
19 
48s 
84 
12 
72 
3 ° 
54 
22 
8 
8 
0 
8 
0 
8 
24 
24 
10 
24 
0 
24 
93 
61 
32 
92 
1 
* 84 
74 
52 
22 
73 
1 
68 
36 
33 
3 
36 
0 
36 
86 
63 
23 
86 
0 
84 
S* 
3 i 
25 
56 
0 
55 
84 
55 
J 9 
80 
4 
78 
429 
29s 
134 
423 
6 
405 
Another cross which was followed up with great care was a cross of 
resistant flax No. 4, with susceptible No. 6. Reciprocal crosses were 
made, and selfed seed was obtained from both parent plants. The 
resistant parent is designated as 4E1 and the susceptible parent as 
6E1. The first generation (PI. 45, A, b t c) proved to be entirely suscept- 
23717°—17 - 5 
