May 19, 1923 
Life History of Stripe Rust 
617 
Tabi,B IV .—Development of rust on plants grown in the field at Corvallis^ Oreg,y in iQiQi 
from rusted and unrusted seed sown on Oct. 20, igiS 
No. 
Variety. 
Condition of seed 
Number 
of rod 
rows. 
First rust appeared* 
I 
Salt Lake Club. 
Slight infection. 
10 
None until spring. 
2 
Chul. 
Heavy infection. 
10 
Do. 
7. 
Dale (Dale Gloria).. 
Clean seed. 
10 
Do. 
0 
4 
Baart (Early Baart). 
.do. 
10 
Do. 
Talimka. 
.do. 
10 
Do. 
6 
Dale. 
Medium infection. 
10 
Do. 
7 
Federation. 
Clean seed. 
10 
Do. 
8 
Chul. 
Heavy infection. 
10 
Tan. 20. loio. 
0 
Baart. 
Slight infection. 
10 
Dec. i<. 1018. 
10 
Hansia Brooch. 
Heavy infection.. 
10 
Feb. II, 1919. 
II 
Popatia Nadiad.... 
10 
None until spring. 
greenhouse experiments 
In addition to the field experiments given above, greenhouse experi¬ 
ments have been carried on under controlled conditions. In order to 
grow a large number of wheat plants from seed infected with stripe rust, 
a portion of one of the greenhouses at the Oregon Agricultural College 
was equipped in the following manner: A partition was built to isolate 
completely one corner of the greenhouse; double doors were arranged in 
such a manner that anyone entering the isolated room could pass into 
a vestibule and close the first door before the second one was opened; 
the vestibule between the two doors always was sprayed with water 
before entering. A system of forced circulation of washed air was 
installed, as shown in figure i. 
The author (< 5 ) has reported upon this same system of air washing as 
it was used in connection with similar studies with wheat kernels infected 
with P, graminis tritici. Every precaution was taken to guard against 
any possible infection from outside. The room was made tight by using 
roofing cement to seal all cracks and openings in the sides and roof. 
The first experiment was started on December 24, 1918. The seed 
used was for the most part from varieties grown in the rust nursery at 
Corvallis. It consisted of hand-picked kernels, all of which showed 
unmistakable evidence of stripe-rust infection. The varieties used were 
Hansia Brooch (C. I. No. 4690), Popatia Nadiad (C. I. No. 4696), Talimka 
(C. I. No. 2495), Baart (C. I. No. 1697), and Chul (C. 1 . No. 2406). In 
this, as in all other experiments of this series, temperature and humidity 
records were kept and it was found possible to maintain the temperature 
and relative humidity within the normal limits of plant growth. Flats 
filled with about 5 inches of sandy-loam soil were used for growing the 
plants. In all, 1,465 wheat plants were grown to maturity in this ex¬ 
periment, and no rust appeared on any of these plants at any time. 
The second experiment was started on November 20, 1919. Wheat 
kernels were picked in the same manner as for the first experiment and 
the same methods were followed. Chul wheat (C. I. No. 2406) was used 
for the entire lot of plants in this experiment. The total number of 
plants grown was 2,470. No rust appeared at any time on any of the 
plants grown from this rust-infected seed and the experiment was 
discontinued when the wheat was mature. 
