RUST RESISTANCE IN WINTER-WHEAT VARIETIES. ~ % 
The varieties grown in the rust nursery included the commonly 
grown hard red winter wheats of the Crimean group, such as Turkey 
and Kharkof, and the varieties of soft red winter wheat grown in 
eastern Kansas and other soft red winter-wheat districts. Some of 
_ the varieties were obtained from the Office of Cereal Investigations 
of the Bureau of Plant Industry and others from the agricultural 
experiment stations of other States. The strains grown under a 
pedigree number, and so designated in Table 1, represent pure-line 
selections made by Prof. H. F. Roberts, formerly of the department 
of botany, Kansas Agricultural Experiment Station. These strains © 
were turned over to the department of agronomy in 1910, and seed 
was obtained from that department when the study of wheat varie- 
ties for rust resistance was begun. Not all the varieties have been 
grown throughout the period of experiment, because some of them 
were found to be of little or no agronomic value. Some were shown 
to be extremely susceptible to stem rust, and others were eliminated 
because of complete winter killing. A small number of spring- 
wheat varieties were grown, to obtain comparative data on rust 
infection. 3 
BREEDING PLAT. 
Certain varieties of spring and winter wheats were grown in a 
breeding plat each year to serve as material for crossing. The 
winter-wheat varieties were sown in the fall at the time the varieties 
were sown in the rust nursery. Considerable space was left between 
the rows of winter wheat, to allow for seeding spring wheats for 
crossing. Occasionally a few of the spring varieties bloomed at the 
same time as the winter wheats, thereby simplifying the work of 
making the crosses. Generally, however, it was necessary to sow 
such spring varieties in the greenhouse about the first of February. 
These were transplanted to the breeding nursery in April and May, 
thus providing some of the spring-wheat plants, which were in flower 
at the same time as the winter varieties. : 
Crosses have been made between Kanred (Kansas No. 2401), 
Kansas No. 2414, and Kansas No. 2415,° three closely related winter- 
wheat varieties which are resistant to leaf rust (31) and to certain 
strains of stem rust (29, 30); also between Marquis, Haynes Blue- 
stem, and Preston, varieties of spring wheat which are susceptible 
to stem rust. The F,, F,, and F, generations have been grown to 
maturity, and data on the inheritance of resistance to stem rust 
(Puccinia graminins tritict) have been obtained. These results, 
however, are not presented in this bulletin. 
¢These varieties have been known as P762, P1968, and P1066, respectively. They have recently 
been given Cereal Investigations numbers as follows: C. 1. 5146, C. I. 5879, and C. I. 5880, respectively. 
