Jan. a, 1930 



Treatment of Cereal Seeds by Dry Heat 



385 



EXPERIMENT 4 



The fourth experiment was started April 25 and completed April 26, 

 1918, the seed being heated for 30 hours. The same gas oven was used as 

 for the third experiment. It was watched in the same way and the tem- 

 perature range held the same, 95° to 105° C, averaging about 100°. 

 Seed samples of about i pint were again used, but in this fourth experi- 

 ment wheat, oats, and rye were tested. 



In Table IV are given the results of greenhouse germination tests on 

 the untreated and treated seed of both the third and fourth experiments. 



Table IV. — Effect of dry-heat treatment in experiments j and 4 on germination 



Kind of grain. 



Variety. 



Percentage of germina- 

 tion. 



Heated for 



30 hours 

 at 100° C. 



Barley. 

 Do 

 Do 

 Do 

 Do 

 Do 

 Do 

 Do 

 Do 

 Do 

 Do 



Wheat. 

 Do 

 Do 

 Do 



Rye. .. 



Oats. .. 

 Do 



Beldi 



Beldii. 



Chevalier 



Oderbrucker (a) ^ 



Oderbrucker (b) 



Oderbrucker (c) 



Oderbrucker (d) 



Oderbrucker (e) 



Oderbrucker (f) 



Manchuria 



Manchuria (Wisconsin pedigree No. 9) 



Kubanka (South Dakota No. 75) 



Preston (South Dakota No. 67) 



Kanred 



Kharkov 



Winter rye 



Mixed variety 



Swedish Select 



86 

 53 

 85 

 95 

 94 

 100 

 92 

 95 

 95 

 97 

 97 

 66 



95 

 100 



97 

 92 

 96 

 95 



55 

 63 

 71 

 64 

 79 

 31 

 59 

 66 



85 

 58 

 83 

 30 

 53 

 98 

 80 

 16 

 65 

 57 



1 Seed hand-picked from plants distinctly infected with bacterial blight in the heads. 



' Oderbrucker a, b, c, etc., represent samples of same variety but from different sources. 



It is evident from Table IV, as from Table I, that seeds of these various 

 cereals withstand this severe drying surprisingly well. While with cer- 

 tain samples the germination was cut down severely, as with rye and 

 Preston wheat, it should be noted that both of these were rather shrunken, 

 especially the Preston wheat. The Kubanka wheat was also a weak 

 sample. 



The seed of the wheat varieties, Kubanka (South Dakota No. 75) and 

 Preston (South Dakota No. 67), used in experiment 4, carried a consid- 

 erable amount of scab infection (Gibberella saubinetii and Fusarium spp.). 

 The untreated grain from both samples when sown in the greenhouse for 

 the germination test gave a considerable number of plants showing seed- 

 ling infections. The bases of many plants were discolored, and some 

 plants were killed even before reaching the surface (Pi. 49, B, at left). 



