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Experiments with cereals have been conducted cooperatively since 1904 at College Park, Md., by the Maryland Agricultural Experiment Station and the Office of Cereal Investigations. 1 Similar experiments have been conducted by the Office of Cereal Investigations on the Arlington Farm, Rosslyn, Va., since 1907. 2 These experiments have consisted mainly of varietal tests and extensive breeding operations with the most important winter cereals. This bulletin is for the most part a report of the varietal tests. The varietal testing has J The preliminary cereal work conducted at College Park, Md., prior to 1907 was under the supervision-of Mr. Mark Alfred Carleton, Cerealist of the Bureau of Plant Industry. Mr. H. A. Miller, a scientific assistant in the Office of Cereal Investigations, was in immediate charge. On October 1, 1907, when cooperative cereal investigations were begun with the Maryland station , Mr. V. M. Shoesmith, then agronomist at the station, was made collaborator. From the time of Mr. Shoesmith's resignation on January 1, 1908, Mr. C. W. Nash, assistant agronomist at the station, acted as collaborator to September 1, 1909. On the latter date Mr. N. Schmitz was appointed agronomist of the Maryland station, since which time he has been collaborator. 2 The Arlington Farm is located in Virginia on the southern bank of the Potomac River, just opposite and to the west of the city of Washington, D. C. The experimental work with cereals has been under the direction of the men in charge of wheat, oat, and barley investigations in the Office of Cereal Investigations. From 1907 to 1912 Mr. H. B. Derr supervised the work with barley and wheat at the Arlington Farm. Since that time the work with these cereals has been in charge of Drs. H. V. Harlan and C. E. Leighty, respectively. Mr. C. W. Warburton has been in charge of the work with oats during practically the entire period.

R ESULTS on the inheritance of smut resistance in crosses between Mar kton and certain other oat varieties were reported in a previous paper. 3 Markton is very resistant to the specialized races of both loose smut (Ustilago avenae (Pers.) Jens.) and covered smut (U. levis (K. and S.) Magn.), that have been used by the senior author in his experiments. Of the other varieties used as parents, Canadian, Early Champion, and Victor are susceptible to both smuts, Gothland is susceptible to loose smut but resistant to covered smut, while Monarch is resistant to loose smut and susceptible to covered smut. Results with eight additional hybrids are presented in the present paper. These may be classified into three groups, based on the reaction of the parental varieties to the specific physiologic races of the loose and covered smuts. MATERIALS AND METHODS Group r involved crosses of the variety Victor, susceptible to both smuts, with Seizure and Scottish Chief susceptible to loose smut but resistant to covered smut. Group 2 involved crosses of five varieties susceptible to loose smut and resistant to covered smut with Monarch, which is susceptible to covered smut but resistant to loose smut. These five varieties crossed with Monarch are Gothland, Rossman, Danish, Seizure, and Scottish Chief. Group 3 consisted only of the Danish Island X Monarch cross. Danish Island is very susceptible to loose smut and but slightly susceptible to covered smut. The history of these crosses is the same as for those reported in the previous paper, 4 and the specialized races of the smuts and methods of inoculation are identical. Data were obtained for the F ,, F 3 , and F 4 , and, in some cases, on the F 5 generations, but those for the F 4 and F 5 generations are omitted in this paper. EXPERIMENTAL DATA The data for the parental varieties and those obtained for the F, generation. are given in Table I. The parental varieties, Danish, Danish Island, Gothland, Rossman, Seizure, and Victor, have shown from 89.9 to 96.o% infection with loose smut. Scottish Chief has not shown so high a degree of susceptibility, as only an average of 55-S% of infection with loose smut was obtained. An infection above 75% has never been secured in the many experiments with Scottish Chief. Monarch, on the other hand, has shown a high degree of resistance to this smut, and only 0.4% of the inoculated plants were infected. 1 The investigations reported herein were conducted by the Division of Cereal Crops and Diseases, Bureau of Plant Industry, U.S. Dept. of Agriculture, in cooperation with the Brooklyn Botanic Garden, Brooklyn, N. Y. Brooklyn Botanic Garden Contribution No. 81.