45» 
Journal of Agricultural Research 
Vol. XXIII, No. 6 
Bunt, like the rusts, finds certain species more congenial hosts than 
others. Table I, compiled from the tests of 1919 and 1920 at the Wash¬ 
ington Agricultural Experiment Station, Pullman, Wash., shows the 
comparative resistance of the eight species as tested. 
Table i .—Comparative bunt resistance of the eight species of wheat 
Species. 
Number of 
tests.® 
Total num¬ 
ber of 
plants 
counted. 
Percentage 
of bunt 
produced. 
Einkom (T . monococcum) . 
4 
87 
O. O 
Polish (T. polonicum) . 
3 
66 
7.7 
Emmer (T . dicoccum) . 
10 
*55 
9.6 
Spelt (T. spelta) . 
21 
5 i 5 
9 - 7 
Durum (T . durum) . 
40 
1,256 
29.3 
Poulard (T. turgidum) . 
9 
264 
33 - 5 
Club (T . compactum) . 
98 
4, 296 
64.1 
Common ( 7 \ vulgare) . 
666 
25,009 
70. 2 
® The actual number of distinct races or sorts was but slightly over 500 in round numbers. Many of the 
29x9 plantings were duplicated in 1920. 
Taking the average percentage of bunt produced as the index of 
resistance, the eight species may be arranged into four groups. Ein- 
kom is immune, polish, emmer, and spelt are very resistant, durum 
and poulard are intermediate, and club and common are very suscep¬ 
tible. It would require a much more exhaustive test to establish these 
findings as general laws for specific bunt resistance, but there are two 
deductions that may be made. i. Species of Triticum differ in their 
susceptibility to bunt and in a manner analogous to specific rust resist¬ 
ance and also analogous to their genetic relationships. 2. Spelt forms 
a notable exception, falling into the very resistant class instead of the 
susceptible class that its genetic and rust-resistance relationships call 
for. These relationships are established by the work of several investi¬ 
gators (15, 57, 58 ), and the different behavior of spelt in respect to 
bunt resistance is established in Table 1 by the performance of 21 rows 
and more than 500 plants. 
It has been found that the common and club wheats vary within 
rather wide limits among the different races of the same species, a few 
selections of both being very resistant, more being intermediate, but 
the majority being very susceptible. 
Resistance to some diseases seems to break down when the host is 
grown in another environment. The information available on bunt 
resistance indicates that a wheat resistant to bunt will remain so in all 
climates. For example, Turkey (Washington, No. 326) is resistant 
under conditions favoring maximum infection at the experiment stations 
of Kansas, Minnesota, California, Oregon, Idaho, and Washington. 
A comparison of a large number of varieties, known to be pure lines, 
in two districts of distinctly different climate should give a clear idea 
of the probable constancy of bunt resistance in different environments. 
This can best be done by means of a correlation table in which the 
comparative resistance of each variety in one locality is measured in 
relation to its comparative resistance in the other locality. If there is 
perfect agreement, the coefficient of correlation is 1. If they vary inde¬ 
pendently in each locality, without regard to the comparative resistance 
