2 BULLETIN 1284, U. S. DEPARTMENT OF AGRICULTURE 
distribution, the sorghurns are able to produce larger yields and with 
greater certainty than corn, wheat, and other crops. Consequently, 
the total acreage devoted to sorghums has greatly increased during 
the last few years. In 1903 approximately 2,000,000 acres were sown 
to this crop, and in 1918 more than 6,000,000 acres. The acreage 
in 1919 showed a decrease from that of 1918, yet more than 5,000,000 
acres were grown (100). ? The estimated area in grain sorghums in 
1922 was 5,057,000 acres. 
The sorghums have long been under cultivation in various parts of 
the Old World, and their great diversity is no doubt due to their 
utilization by man in widely separated regions. In India (63) sor- 
ghums occupy third place among cultivated crops, covering an area 
of 21,000,000 acres. In the Bombay Presidency the crop ranks first, 
more than 8,000,000 acres being grown annually, constituting more 
than one-third of the area devoted to the cultivation of grains. In 
parts of northern China (5) the kaoliangs constitute the chief crop of 
the inhabitants. The kafirs, sorgos, and durras are extensively cul- 
tivated in various sections of Africa. Broomcorn is an important 
agricultural product of Italy and Hungary. 
The sorghums are regarded as having been derived from the wild 
species Holcus sorgJwm L. (Andropogon sorgJwm (L.) Brot.) (47, 87, 
118). The wild forms of the species, such as Sudan grass and Tunis 
grass, are distributed in central and southern Africa, Egypt, Mada- 
gascar, and neighboring islands. They are annual plants, without 
rootstocks, and are differentiated into a number of distinct races or 
subspecies. They readily hybridize with the cultivated sorghums. 
A closely related species is Holcus Jialepensis L. (Andropogon Jiale- 
pensis (L.) Brot.), which includes the perennial forms with root- 
stocks, such as Johnson grass and related forms. The various races 
or subspecies are widely distributed in southern Europe, northern 
Africa, and western Asia. Hybrids between Johnson grass and the 
sorghums have rarely been observed, and attempts to cross them 
artificially are only occasionally successful. 
Sorghums, like other crops which are extensively cultivated, are 
subject to many diseases. The sorghum smuts, however, are gener- 
ally recognized as the most destructive diseases of sorghum, and 
much attention has been given to them in order to determine their 
life histories and methods of controlling them. 
SMUTS ATTACKING SORGHUMS 
The primary purpose of the investigations described in this bulletin 
was the determination of the behavior of the different varieties of 
cultivated sorghums with reference to their susceptibility or resist- 
ance to the covered kernel smut, S pJiacdotJieca sorgJii (Link) Clinton, 
and the head smut, Sorosporium reilianum (Kiihn) McAlpine. No 
extensive studies of this nature have been conducted, although 
mention has frequently been made of the occurrence of smut on 
broomcorn, sorgos, kafirs, durras, and kaoliangs. The absence of 
smut on milo and feterita has been noted frequently. If certain 
sorghums, such as milo and feterita, possess a marked degree of 
resistance to the smuts, they furnish a sound basis for conducting 
breeding experiments for the improvement of sorghums by combining 
2 The figures in italic within parentheses refer to the bibliography at the end of this bulletin. 
