50 
Studies on the Inheritance of Resistance of Oat Hybrids to Loose 
and Covered Sinuts 
The investigation of the inheritance of smut resistance in oat 
hybrids was continued. [Experiments were carried out with the 
third, fourth and later generations of various hybrids which in- 
volved crosses between varieties of oats differing in their reaction 
to the Missouri races of the two smuts of oats. 
Experiments with the Third Generation of Oat Hybrids.— 
Hybrid 80, Canadian X Monarch Selection, is a cross between 
Canadian, susceptible, and Monarch Selection, resistant to the 
covered smut. [Extensive data on the reaction of the third gen- 
eration progenies of this hybrid to this specialized race of covered 
smut were reported last year. A few additional progenies have 
been grown, and the results are comparable to those previously 
obtained. There were 30 third generation progenies, of which 4 
were resistant, 18 segregating, and 8 susceptible. Resistant prog- 
enies are those which contain no smutted individuals; susceptible 
progenies regularly give a very high percentage of infection, fre- 
quently as much as 100 per cent.; segregating progenies are those 
which include 50 per cent. or less infected plants. 
Hybrid 81 is a cross between Gothland, which is very suscepti- 
ble, and Black Mesdag, which is resistant to the loose smut. Some 
additional data, supplementary to that reported a year ago, have 
been secured. There were 30 thir¢ 
an 
generation progenies, of which 
S were resistant, 15 segregating, and 7 susceptible. These results 
are in harmony with those previously recorded for this hybrid. 
Hybrid 82 is a cross between Danish Island and Monarch. 
Danish Island is susceptible to the loose smut, while Monarch is 
resistant. Monarch, however, is very susceptible to the covered 
smut, and Danish Island ts only slightly so. There were two series 
of third generation progenies inoculated. In one series 180 third 
generation progenies were inoculated with loose smut, and 78 were 
classified as resistant, 79 as segregating, and 23 as susceptible. 
These results correspond fairly well with those recorded in the 
previous year. There was a conspicuous preponderance of re- 
sistant progenies in comparison with the susceptible, and accord- 
ingly, the behavior of this hybrid does not correspond fully with 
that of Hybrid 81. 

