RELATIVE RESISTANCE OF WHEAT TO BUNT 5 
tion shows bunt infection under any condition it is known to be not 
immune, and such varieties as are not immune or highly resistant are 
not considered worthy of continued testing. Immune or highly 
resistant varieties should be subject to conditions as favorable as 
possible for bunt infection in order to determine their degree of 
resistance. These are the wheats desired to serve as resistant parent 
stocks for hybridization studies. 
RESULTS WITH AMERICAN WHEATS 
The results obtained in bunt experiments with American wheat 
varieties and selections are presented in Tables 1 to 4, inclusive. 
Data on commercial varieties of common wheat are given in Table 1, 
but results with selections of hard red winter wheat and a few results 
on head selections of Pacific Bluestem, a white wheat, are given in 
the text only. 
Full data on a few of the most bunt resistant of the selections of hard 
red winter wheat are presented later in Table 8, under the heading 
"Resistant varieties." 
Data similar to those for common wheat are presented for club 
wheats in Table 2 and for durum wheats in Table 3. Results of experi- 
ments on minor wheat groups, such as ernmer, spelt, poulard wheat, 
Polish wheat, and einkorn, are shown in Table 4 and the accompany- 
ing text. 
COMMON WHEATS 
In preparing the data the common wheats are separated into " Com- 
mercial varieties 7 ' (Table 1) and "Selections" (not tabulated). 
COMMERCIAL VARIETIES 
The percentages of infected heads in the commercial American 
varieties of common wheat are shown in Table 1. The common 
wheats are here divided into four commercial classes (hard red spring, 
hard red winter, soft red winter, and white) . The recognized varieties 
are listed in alphabetical order, following the nomenclature used in 
the " Classification of American Wheat Varieties," by Clark, Martin, 
and Ball (1). All names of synonymous varieties are listed together 
in alphabetical order or in the order of their Cereal Investigations 
( C. I.) numbers under the recognized varietal names. Data are shown 
for only the varieties and selections which have been grown in the 
bunt experiments during two or more station years. 
The varieties consist largely of those assembled for the study of 
wheat classification by members of the Office of Cereal Investigations. 
Many were grown from seed selected from individual heads in previous 
seasons and thus are pure-line selections, whereas others represent 
merely the mass variety. It may be possible, therefore, that other 
pure lines of these varieties would show different degrees of bunt 
infection. Two or more strains of nearly ail varieties were grown in 
the bunt experiments, so that the behavior of the variety as a whole 
is fairly well indicated. 
