RUST RESISTANCE IN WINTER-WHEAT VARIETIES. Cal ee 
crop as a result of the production of Kanred wheat would be $21,000,- 
000. A statement of the agronomic value of this variety will be 
found in Circular 194 of the United States Department of Agriculture. 
Although the problem of breeding wheat for resistance to stem rust 
has been greatly complicated by recent discoveries of a number of . 
distinct biologic strains of rust which are present in the several grain- 
growing regions, Kanred wheat in the future probably will prove of 
ereat value as a parental variety in crosses, for it certainly contains 
factors for resistance to some strains of leaf rust and stem rust. 
There is good evidence that these factors are transmitted in wheat 
hybrids in the same general way as the factors for other characters. 
Kanred wheat is being used by the Tennessee Agricultural Experi- 
ment Station as the rust-resistant parent in a series of crosses with 
adapted varieties of soft red winter wheat, in the hope of producing 
varieties of soft red winter wheat resistant to leaf rust and otherwise 
equal to the best varieties now being grown, which are often severely 
damaged by leaf rust. Kanred also has been used at the Kansas 
and Minnesota Agricultural Experiment Stations as a parent in a- 
large number of crosses. It is too early to make any predictions as 
to the value of any of these hybrids, although several of them appear 
promising. 
SUMMARY. 
(1) Field experiments to determine the resistance to black stem rust 
(Puccinia graminis triticr) of about 100 varieties and strains of winter 
wheat, many of them pure-line selections, and of a few varieties of 
spring wheat, were conducted in a rust nursery at Manhattan, Kans., 
in 1915, 1916, and 1917. Greenhouse experiments were conducted 
during the winter of 1916-17, using the same varieties. Special 
methods were developed for producing rust epidemics under the pre- 
vailing climatic conditions of Kansas. 
(2) In the rust nursery severe epidemics were produced each 
season, and the percentage of rust infection probably represented 
the maximum rust attack which the varieties old encounter under 
field conditions. 
(3) All the winter-wheat varieties grown were found to be suscep- 
tible to stem rust except Kanred and two very similar pure-line 
selections, P1066 and P1068. These three varieties were found to be 
resistant. Another pure-line strain, Kansas No. 2390, gave evidence 
of being partially resistant. 
(4) Plumpness of kernels usually is reduced by severe rust attack. 
The three resistant varieties produced grain of good quality in 1916 
and 1917, when other varieties grown under the same conditions 
but much more severely rusted produced very badly shrunken 
kernels. | 
