4 BULLETIN 1046, U. S. DEPARTMENT OF AGRICULTURE. 
NURSERY EXPERIMENTS. 
METHODS AND MATERIALS. 
Because of the infrequent occurrence of natural epidemics of stem. 
rust under Kansas conditions,® it was necessary to study varietal 
resistance in a rust nursery (PI. I, figures 1 and 2), following the gen- 
eral plan suggested by Johnson (20). This rust nursery was located 
near Manhattan, Kans., on land which is low and slopes slightly 
toward the south and west. Along the south side of the nursery is 
a hedge of common barberry bushes (PI. I, fig. 2). A large drainage 
ditch on the south side carried off the surplus water. Because of 
the likelihood of frequent heavy rains during the crop season, the 
rust nursery was sown in slightly elevated plats; separated by de- 
pressed alleys, which received the surplus water and carried it into 
the main ditch. The rust nursery has been sown in various ways. 
At first a plat 1 rod square was used for each variety, but it was 
found impossible to produce severe epidemics of stem rust on large 
areas under Kansas conditions. ‘The plats, therefore, were reduced 
to a single rod row and in 1915 to 5-foot nursery rows spaced 10 
inches apart. The seeds are sown 3 inches apart in the row. A 
small hand plow was used for opening a furrow and a seeding board 
with notches at regular intervals served to obtain uniformity in 
spacing the seed. 
The spring varieties generally were sown during the last week in 
March or the first week in April in rows close to the winter-wheat 
rust nursery. 
The rust used in these experiments up to and including 1917 was 
obtained from the Minnesota Agricultural Experiment Station. In 
1914, 1915, and 1916 the urediniospores came from greenhouse cul- 
tures of Puccinia graminis tritici, but in the fall of 1917 cultures 
were used from rusted wheat plants obtained in the field. These 
were found later to be a new strain of stem rust (30). The stock 
cultures of rust which were used in these field experiments were 
cultured on Improved Turkey (Kansas No. 2382), a variety which 
has been found in these experiments to be very susceptible to stem 
rust. When the leaves produced uredinia which were sporulating 
abundantly they were used in one of two ways: (1) The leaves 
were clipped from the plants, placed in a few quarts of water, the 
urediniospores removed, and the liquid used as a spray on the wheat 
plants in the rust nursery, or (2) the potted wheat plants bearing 
uredinia were used as centers of infection in the nursery. 
5 The only natural epidemic known to the writers occurred in 1904. In 1915 and 1916 stem rust was very 
prevalent in many fields in Kansas and in some instances there wasan appreciable loss. In 1919 stem rust 
was uniformly present in eastern and central Kansas, and although it was difficult to estimate the actual 
injury caused by stem rust it was one of several factors which reduced the yield and quality of wheat. 
