97 



A Test of Indiana Varieties of Wheat Seed for 

 Fungous Infection. 



Geo. N. Hoffer. 



"ludiaiia grows annually more than 2,500,000 acres of wheat. The aver- 

 age yield for the past ten years has been 15.1 bushels per acre.'" — Clr. No. 

 23, Purdue University Agr. Exp. Sta. 



The economic significance of any factor which plays a part in causing 

 c decrease in the quantity of the yield, even though this decrease may be 

 represented by a fractional part of one per cent, of the yield, is considerable. 

 The mere presence, then, of internally infecting fungi in the wheat seed 

 studied in the laboratory may be indicative of very important problems in 

 the field. 



In Bulletin No. 203 of the Ohio Agricultural E.vperhneut Station. T. 

 F. Manns has described a method for detecting fungi internally infecting 

 wheat and other small grain. The nietliod in brief, consists in sterilizing the 

 outside of the grain by means of a solution of corrosive sublimate in 50 per 

 cent, alcohol and then placing the seeds in sterile petri dishes on agar-agar. 

 This allows germination of the plant embryo when viable. Cultures 

 or growths of the fungi surviving internally in the seed develop at the 

 same time. The fungi in these cultures can then be identified. 



The results of laboratory tests at the Ohio station "show an amazing 

 amount of disease transmission in seed wheat as well as the proof of scab 

 infection by both germinating and dead wheat kernels." A study of field 

 conditions showed "that many seedling wheat plants were killed by the scab 

 fungus (Fusarium roseum) conveyed in the seed or retained by the soil." 

 This verified the laboratory conclusions. 



In the report of the botanist of the North Dakota Agricultural Experi- 

 ment Station for 1011, Dr. H. L. BoUey concludes from the results of numer- 

 ous tests of seeds that "our experiments, taken as a whole, tend to prove 

 definitely that the soU is not often materially depleted, but that the deteri- 

 oration in j'ield and quality of grain is more specifically to be assigned to 

 troubles caused by internal seed infection and soil infection." 



7—1019 



