STERILITY OF OATS. 
Table II. — Average percentages of sterility in 11 varieties of oats, as shown by inoculc tion 
experiments in 1918. 
Variety, 
Untreated, 
uninjured. 
Sprayed with water. 
Uninjured. Injured 
Sprayed with organism. 
Uninjured. Injured 
Wisconsin Pedigree 1. 
Wisconsin Pedigree 3. 
Wisconsin No 4 
Wisconsin Pedigree 5. 
Wisconsin Pedigree 7. 
Wisconsin Pedigree 13 
Wisconsin Pedigree 14 
Wisconsin Pedigree 15 
Wisconsin No. 22 . . 
Wisconsin N o. 25 
Wisconsin N o. 49 
0.4 
25 
29 
63 
{ S \ 
On normal untreated plants of the 11 varieties tested the amount of 
sterility varied from a fraction of 1 per cent to as much as 16 per cent. 
Sprayed with water suspensions of bacteria and with sterile water 
and treated as previously described, the proportion increased from 2 
to 47 per cent. In some cases there was more sterility on plants 
spra}^ed with bacterial suspensions than on plants of the same variety 
sprayed with sterile water. In other varieties the reverse was true. 
On the whole, the amounts of sterility produced by either method 
seem to be about equal. If this is so, the bacteria are not the cause 
of the sterility in the varieties included in these experiments. 
Wisconsin Pedigree -7 oats were sprayed when the panicles were 
entirely out and the spikelets practically full size. Although every 
spikelet was yellowed with halo lesions, the spikelets continued to fill 
out, as in untreated panicles. 
In a plat of Wisconsin Pedigree 14 oats which was untreated a few 
panicles appeared which showed halo lesions on from a few to all of 
the spikelets in a panicle, but in spite of these lesions the spikelets 
were apparently as well developed as those unspotted. 
EXPERIMENTS OF 1920. 
During the season of 1920 panicles of oats were collected 'at random 
in oat fields and counts made of sterility; also another set of experi- 
ments was carried on to learn more of the possible relation of bacteria 
to sterility in oats. Bacterial suspensions and sterile water were 
sprayed into the unopened sheaths of plants about two-thirds grown. 
These were covered with glassine bags for three days, as in previous 
experiments. The results of these tests are shown in Tables III 
and IV. 
