reb. 15 ,1925 Smut Susceptibility of Selections from an Oat Hybrid 391 
suit, observations were made on the 
relative plant height in some of the F 3 
progenies. Of the F 3 progeny of F 2 
plant No. 1015al-45, some wereftall 
like Swedish Select, and others were 
short like Fulghum. Similar varia¬ 
tions in plant height were indicated in 
some of the other families that proved 
very resistant to smut. In the very 
susceptible families No. 1015al-52 and 
No. 1015al-54, indications of marked 
variation in plant height also were 
observed. 
These observations, therefore, indi¬ 
cate rather definitely that the plant 
characters of either parent are not 
correlated with smut resistance or smut 
susceptibility. The factors for smut 
resistance apparently are inherited in¬ 
dependently of morphological charac¬ 
ters in the cross in question (Fulghum X 
Swedish Select). 
CONCLUSIONS 
1. The behavior of 92 F 3 families of a 
cross between Fulghum and Swedish 
Select to Ustilago avenae and U. levis 
has been studied. A very wide range of 
susceptibility of the families has been 
noted. A large majority of the families 
have shown a moderate or high degree 
of susceptibility Twenty-five families 
have shown a resistance comparable to 
that of the resistant Fulghum parent, 
and eight families a susceptibility 
greater than that of Swedish Select. 
2. The F 4 selections from susceptible 
F 3 families all proved to be highly sus¬ 
ceptible, whereas the F 4 selections from 
resistant F 3 families in general have 
been very resistant. In one case, how¬ 
ever, two of the latter selections showed 
rather high percentage of infection. 
3. The selections appear to behave in 
a similar fashion toward both loose and 
covered smut. These results are in 
harmony with those obtained by Reed 
(14) and Reed, Griffiths, and Briggs 
(15) in connection with their studies on 
the varietal resistance of oats to loose 
and covered smuts. Very few varieties 
of oats have been found which show any 
marked differences in their resistance 
to the loose and covered smuts. 
4. There appears to be no correlation 
between morphological characters of 
the various selections and their suscep¬ 
tibility to the smuts. Certain F 3 fam¬ 
ilies with the general characters of 
Fulghum have been found to be highly 
susceptible. On the other hand, some 
families more or less similar to Swedish 
Select have proved to be highly resist¬ 
ant. Thus it is possible to obtain the 
desired combination of resistance to 
smut and other varietal characters of 
oats. 
LITERATURE CITED 
(1) Aamodt, O. S. 
1923. THE INHERITANCE OF GROWTH HABIT AND 
RESISTANCE TO STEM RUST IN A CROSS BETWEEN 
TWO VARIETIES OF COMMON WHEAT. Jour. Agr. 
Research 24: 457-470, illus. 
(2) Armstrong, S. F. 
1922. THE MENDELIAN INHERITANCE OF SUSCEP¬ 
TIBILITY AND RESISTANCE TO YELLOW RUST 
(PUCCINIA GLUMARUM ERIKSS. AND HENN.) IN 
WHEAT. Jour. Agr. Sci. 12: 57-96. 
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1924. THE INHERITANCE OF SMUT RESISTANCE IN 
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(4) Biffen, R. H. 
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(5) Fraser, A. C. 
1919. THE INHERITANCE OF THE WEAK AWN IN 
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OTHER CHARACTERS OF THE OAT GRAIN. N. Y. 
Cornell Agr. Exp. Sta. Mem. 23, p. 629-676, 
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(6) Gaines, E. F. 
1920. THE INHERITANCE OF RESISTANCE TO BUNT 
or stinking smut of wheat. Jour. Amer. 
Soc. Agron. 12: 124-132. 
(7) - 
1923. GENETICS OF BUNT RESISTANCE IN WHEAT. 
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(8) Garber, R. J. 
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(9) Harrington, J. B., and Aamodt, O. S. 
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(10) Hayes, H. K., and Aamodt, O. S. 
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(11) - Parker, J. H., and Kurtzweil, C. 
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(12) Melchers, L. E., and Parker, J. H. 
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O 
