RUST RESISTANCE IN WINTER-WHEAT VARIETIES. 7 



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 Burbau 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. 



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^, Fj, and F3 generations have been grown to 

 maturity, and data on the inheritance of resistance to stem rust 

 (Puccinia graminins tritici) have been obtained. These results, 

 however, are not presented in this bulletin. 



• These varieties have been known as P762, P1068, and P1066, respectively. They have recently 

 been given Cereal Investigations numbers as follows: C. 1. 5146, C. I. 5879, and 0. 1. 5880, respectively. 



