oF 
64, Rossman & Monarch. Rossman is susceptible to loose smut 
anc 
er 
resistant to the covered, while Monarch is exactly the reverse 
in its behavior. The progenies showed independent behavior with 
reference to these two smuts. In the series inoculated with the 
loose smut, 5 were resistant, 23 gave less than 50 per cent. infec- 
tion, and 5 gave more than 70 per cent. In the series with the 
covered smut, 13 progenies were resistant, 12 gave less than 50 per 
cent. infection, and 8 more than 50 per cent. 
ivperiments with the Fourth Generation of Hybrids. In 
former reports, the data on many additonal oat hybrids have been 
recorded and, during the past year, fourth generation progenies 
of some of these were grown. 
Hybrid 18, Silvermine X Black Mesdag, was represented by 69 
progenies, and Hybrids 34 to 36, Early Champion & Black Mes- 
dag, by 42 progenies. Practically all of these in all the hybrids 
had descended from resistant third generation families. Silver- 
mine and Karly Champion are both very susceptible to loose and 
covered smut, while Black Mesdag is resistant to both and, 
throughout the second, third, and fourth generations, the hybrids 
have shown a very similar behavior to loose and covered smut. 
During the past few vears very extensive data have been accumu- 
ated on these two sets of hybrids, and have been prepared for 
early publication. 
— 
There were 85 fourth generation progenies of Hybrids 29 to 
32, lulghum x Black Mesdag, tested with the Fulghum Race of 
oose smut. Most of these had descended from resistant third 
generation progenies, and complete resistance to the special race 
of loose smut was established in the fourth generation. 
A large number of fourth generation progenies of Eybrids 50 
to 69, involving various combinations of crosses, were grown. 
— 
The accumulated data are valuable in determining the mode of in- 
heritance of smut resistance in these various types of hybrids. 
Separate sets of progenies, one inoculated with loose smut and the 
other with the coverec 
ear 
, were planted. 
Physiologic Races of Oat Smuts 
Further experiments were carried out with some of the physio- 
pay 
logic races of both loose and covered smut. The most extensive 
