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UNITED STATES DEPARTMENT OF AGRICULTURE 



msm BULLETIN No. 105 



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Contribution from the Bureau of Plant Industry 

 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 

 are 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 C1909), 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 

 ;il weeks before the panicle emerges. 



1 Tiir-,(t experiments wen began at the nigga tlon at Prof. i>. u. Jones, of Madison, wis. 

 ■ Mans , Thomai i . Thi Wade blight of oats— a bacterial disease. Ohio Agr. Exp. Sta. Bui; 210, p. 101 , 

 pi. 14. 1909. 



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