June 23,1923 
Inheritance of Resistance to Puccinia graminis 
987 
resistant^ 70 heterozygous, 15 near-susceptible, and 104 susceptible; of 
those from white-seeded parents, i was classed as resistant, i near- 
resistant, 14 heterozygous, 5 near-susceptible, and 24 susceptible. A 
brief comparison of these two sets of figures reveals their similarity, 
that is to say, no correlation of seed color with resistance or suscepti¬ 
bility to rust was indicated. 
Mindum X Pentad Fg families when inoculated with Form I gave the 
following results: Of those from red-seeded parents, 23 were classed as 
immune, 7 near-immune, 39 heterozygous, 6 near-susceptible, and 6 
susceptible; of those from white-seeded parents, 21 were placed as 
immune, 6 near-immune, 43 heterozygous, 4 near-susceptible, and ii 
susceptible. Here again the distribution of families from red seed was 
similar to that of the progeny of white-seeded plants. A lack of corre¬ 
lation of seed color with resistance or susceptibility to rust was evident. 
Mindum X Pentad Fg families when tested with Form XXXIV reacted in 
the following ways: Of those from red-seeded parents, 9 appeared resistant, 
2 near-resistant, 48 heterozygous, 10 near-susceptible, and ii susceptible; 
of those from white-seeded parents, 5 were classed as resistant, 4 near- 
resistant, 20 heterozygous, i near-susceptible, and none susceptible. A 
comparison of the distribution of the progeny of the red-seeded parents 
with that of families arising from white-seeded parents shows differences 
in the near-susceptible and susceptible classes. These, however, can not 
be given much weight owing both to the small number of families classi¬ 
fied and to the fact that Mindum, the white-seeded parent, was suscep¬ 
tible, whereas only i of the 30 families from white-seeded Fg was in the 
near-susceptible and susceptible classes. If anything, a negative corre¬ 
lation is indicated. 
A summarization of the data concerning the mode of inheritance of 
rust resistance with respect to seed color shows that no correlation was 
found to exist between the two. It is important to note that each of the 
three sets of data shows everal Fg families which were homozygous for the 
reaction of the Pentad parent and also homozygous for the seed color of 
Mindum or Kubanka No. 8 parents. Rust resistance and seed color 
appeared to be inherited independently. 
R^SUIvTS OF INOCUI^ATIONS OF KUBANKA NO. 8 X PFNTAD Fg FAMIUFS WITH 
BIOIvOGIC FORM XXXIV. 
The data obtained for Kubanka No. 8 X Pentad with Form XXXIV are 
summarized in Table IV. About 35 control pots of Kubanka No. 8 were 
inoculated. Of the 308 plants that were infected, 21, or about 7 per cent, 
had type i infections and 287 showed types ranging from x- to 4. In 
view of the fact that possible errors and variations may result in types of 
infection outside of the normal range, the type i infection on these 21 
plants was regarded here as exceptional. The range of infection types 
on Kubanka No. 8 tested with Form XXXIV was therefore considered to 
be from x— to 4 (PI. I, B). All Kubanka No. 8 pots with plants giving 
types of infection falling within this range were classified as susceptible. 
Tfhose pots with 9 or more plants, one of which had a type i infection, 
were placed in the near-susceptible class. Pots having a greater percent¬ 
age of plants with type i infections were classed as heterozygous. The 
distribution of the Kubanka No. 8 pots in the five classes of infection was 
5 heterozygous, 5 near-susceptible, and 25 susceptible. There is no reason 
to believe that 5 of the parent control pots were actually heterozygous 
43326—23-2 
