470 
Journal of Agricultural Research voi. xxiii, No. 6 
Table VIII .—Frequency distribution for resistance to bunt in a cross between two 
varieties of Triticum vulgare, both of which are resistant 
Variety. 
Year 
tested. 
Bunt in parent 
row. 
Numbers falling into classes with average percentage of 
bunt per row of — 
Im¬ 
mune. 
5 
15 
as 
35 
45 
55 
65 
75 
85 
95 
Turkey 326. 
1918 
1919 
1920 
1918 
1919 
1920 
1918 
1918 
1919 
1920 
| 
Per cent. 
0. 5 
.6 
2.4 
. 0 
•9 
8. 1 
Not tested. 
.do. 
I 
6 
11 
5 
2 
2 
1 
1 
29 
1 
2 
8 
1 
Florence 634.... 
226 V62 A F«. 
1 
1 
19 
2 
326X634. Fa 
72 
II 
9 
3 
3 
2 
3 
5 
4 
5 
2 
18 
12 
6 
6 
3 
2 
1 
•J26V624 F.. 
. 0 
. 0 
3-2 
a 67. 7 
. 0 
. 0 
. 0 
. 0 
. 0 
. 0 
226V62A F.. 
5 
2 
1 
1 
3 
I 
a This is evidently a mistake. The row next to it was immune, and it seems probable that the numbers 
got mixed at harvest time, for the three selections showed no trace of bunt the following year. 
In 1919 aif P 3 family of Hybrid 128 X Marquis was produced to test 
the inheritance of the resistance of Marquis to bunt. Information 
regarding the inheritance of Hybrid 128 had been obtained the year 
before from the F 8 generation of the cross between this variety and 
Turkey. The question arose as to whether the seed should be planted 
in the fall or spring, one parent being a winter wheat the other a true 
spring variety. If fall-sown, much winterkilling would be expected, for 
Marquis is not very winter-hardy. If spring-sown the true winter 
segregates would not produce heads and two-thirds of the others would 
be heterozygous for the winter factor and would produce some winter 
plants and some that would develop late so as to interfere with harvesting 
operations. The former course was decided upon and the planting was 
done in October, 1918. The winter was unusually mild, and a good 
stand was harvested the following summer. Every one was surprised to 
find all of the F s rows (334 in number) very badly bunted. The best 
row in the lot was three-fourths smutted, and 276 of the rows produced 
more than 90 per cent of bunt. The whole block of rows appeared as 
a mass of stinking smut which gave off an offensive odor that penetrated 
to windward for half a mile. An examination of some demonstration 
plots in another field showed that the fall-sown Marquis was very 
smutty. This gave a clue as to why all of the F s rows of Hybrid 128 X 
Marquis were badly bunted. The inherent resistance of Marquis was 
broken down by the winter rest period. 
One plant each from nine of the best rows—that is, those having the 
least amount of bunt—and one from each of the four worst rows were 
selected for testing in the F 4 generation. The complete results of the 
parents, the F 2 , F 3 , and these F 4 selections are summarized in Table IX. 
