UNITED STATES DEPARTMENT OF AGRICULTURE 
| BULLETIN No. 1058 
Contribution from the Bureau of Plant Industr7 
WM. A. TAYLOR, Chief 
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Washington, D. C. 
PROFESSIONAL PAPER 
March 6, 1922 
STERILITY OF OATS. 1 
By Charlotte Elliott, Scientific Assistant, Laboratory of Plant Pathology. 
Introduction 
Experiments of 1918. 
CONTENTS. 
Page. 
1 I Experiments of 1920. 
4 I General summary.... 
Page. 
INTRODUCTION. 
At the time when oats are maturing in the field, panicles having 
a part of the spikelets undeveloped or sterile are often sufficiently 
abundant to attract attention and to cause some concern because 
of the resulting reduction in yield. This sterility was first observed 
by the writer in connection with the halo blight of oats. In fields 
showing considerable halo blight there are usually some plants with 
the flag leaf and sheath badly spotted and yellowed. As the panicles 
emerge from these yellowed sheaths, often as many as half of the 
spikelets will be found to be sterile. This sterility usually occurs at 
the base of the panicle, but occasionally part of the upper spikelets 
ate undeveloped. The fact that panicles emerging from yellowed 
sheaths usually show more sterility than panicles from unspotted 
sheaths might lead to the conclusion that the sterility is due to the 
bacterial disease. Thomas F. Manns, in his bulletin on the bacterial 
blight of oats (1909) , 2 describes and figures (pi. 14, p. 161) this 
condition and states that " blast" (sterility) of oats is more or less 
directly proportional to the extent of blade blight. He says that in 
some cases the blast may be due directly to the killing of parts of the 
panicles by contact with blight lesions, but as a rule it is caused by 
the reduced vitality of the plant occasioned by the blade blight 
several weeks before the panicle emerges. 
1 These experiments were begun at the suggestion of Prof. L. R. Jones, of Madison, Wis. 
1 Manns, Thomas F. The blade blight of oats— a bacterial disease. Ohio Agr. Exp. Sta. Bui. 210, p. 161, 
pi. 14. 1909. 
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