Jan, 12,1924 
Soybean Mosaic 
$7 
Table VIII .—Effect of mosaic on yield of seed , IQ22 
Variety. 
Midwest. 
Haberlandt 
Feldun. 
Lexington. 
Dunfield. 
Arlington. 
Manchu. 
A. K. 
Condition of plants. 
Number 
of plants. 
/Healthy 
/Mosaic (seed origin)... 
/Healthy 
(Mosaic 
[Healthy 
(Mosaic 
f Healthy 
(Mosaic 
(Healthy 
(Mosaic 
(Healthy 
(Mosaic 
/Healthy 
(Mosaic 
(Healthy 
1 Mosaic 
28 
95 
22 
13 
6 
5 
7 
6 
4 
4 
6 
4 
3 
3 
9 
8 
Average 
number j 
seeds per j 
plant. 
1 
Average 
yield per 
plant. 
Reduction 
in yield. 
Average 
weight of 
a seed. 
i 
1 
Gms. 
Per cent. 
Gms. 
18.0 
I.85 
0.103 
4.4 
.46 
75 
.105 
22.0 
3.01 
•137 
14.7 
2.04 
32 
.138 
21.6 
3* 2 5 
.141 
14.0 
1.77 
45 
. 126 
22.8 
2.00 
•I 5 1 
12.5 
•93 
53 
•075 
35*7 
4-65 
68 
.130 
13.2 
1.47 
. nr 
40.8 
2.56 
.062; 
6.7 
•23 
93 
• 033 ' 
19*3 
2.40 
. 124: 
10.3 
1.10 
54 
. 106 
27.2 
3*75 
•137 
9.6 
1.14 
69 
. 118 
Owing to the drought, all of the yields were very low in 1922 as com¬ 
pared with 1921. However, the results in Table VIII show that mosaic 
caused heavy losses in all of the varieties. The loss in the Midwest variety, 
of which the greatest number of mosaic plants were available, amounted 
to 75 per cent. All of these Midwest plants represented mosaic of seed 
origin and 37 of the 95 bore no seeds whatever. In the Haberlandt 
variety, however, the average yield of seven plants with mosaic of seed 
origin, not recorded in Table VIII, was only 14 per cent less than that 
of the healthy plants. 
It will be noted that in general the loss was due to the fewer number 
of seeds per plant rather than to the smaller size of the seeds, although 
in the last six varieties the seeds from mosaic plants were considerably 
smaller, especially in the Lexington and Arlington varieties. 
SUMMARY 
No host for soybean mosaic has been found other than the soybean 
itself. 
Varieties of soybean seem to differ somewhat in susceptibility. Mid¬ 
west has proved very susceptible; Soysota and Virginia have shown a 
tendency to escape infection. 
Generally about 10 to 25 per cent of the seed from mosaic plants 
produced mosaic seedlings. 
Varieties seem to differ in their ability to transmit mosaic through the 
seed. Midwest, Haberlandt, Black Eyebrow, A. K., and Arlington 
readily transmitted the disease. 
Marked differences occurred in the percentages of mosaic in the prog¬ 
enies of individual mosaic plants of the same variety. 
The transmission of mosaic seems to bear little or no relation to the 
location of the node at which the seed was produced nor to the date of 
infection of the parent plant. 
The disease has been found in 2-year-old seed saved from mosaic plants. 
73431—24-3 
