STERILITY OF OATS. 



Table II. — Average percentages of sterility in 11 varieties of oats, as shown by inocuU Hon 



experiments in 1918. 



Variety. 



Wisconsin Pedigree 1. 

 Wisconsin Pedigree 3. 



Wisconsin No 4 



Wisconsin Pedigree 5. 



Wisconsin Pedigree 7. 

 Wisconsin Pedigree 13 

 Wisconsin Pedigree 14 



Wisconsin Pedigree 15 



Wisconsin N o. 22 



Wisconsin N o. 25 



Wisconsin No. 49 



Untreated, 

 uninjured. 



16 



10 



7 

 8 



1 

 15 



7 



0.4 



Sprayed with water. 



Uninjured. Injured 



Sprayed with organism. 



Uninjured. Injured 



29 



On normal untreated plants of the 1 1 varieties tested the amount of 

 sterility varied from a fraction of 1 per cent to as much as 16 per cent. 

 Sprayed with water suspensions of bacteria and with sterile water 

 and treated as previously described, the proportion increased from 2 

 to 47 per cent. In some cases there was more sterility on plants 

 sprayed with bacterial suspensions than on plants of the same variety 

 sprayed with sterile water. In other varieties the reverse was true. 

 On the whole, the amounts of sterility produced by either method 

 seem to be about equal. If this is so, the bacteria are not the cause 

 of the sterility in the varieties included in these experiments. 



Wisconsin Pedigree 7 oats were sprayed when the panicles were 

 entirely out and the spikelets practically full size. Although every 

 spikelet was yellowed with halo lesions, the spikelets continued to fill 

 out. as in untreated panicles. 



In a plat of Wisconsin Pedigree 14 oats which was untreated a few 

 panicles appeared which showed halo lesions on from a few to all of 

 the spikelets in a panicle, but in spite of these lesions the spikelets 

 were apparently as well developed as those unspotted. 



EXPERIMENTS OF 1920. 



Dunnir t lie reason of 1920 panicles of oats were collected at random 

 in oat fields and counts made <>F sterility; also another set of experi- 

 ments was carried on to learn more of the possible relation of bacteria 



t<> -tej-iliU in outs. Bacterial suspensions and sterile water were 

 ayed into the unopened sheaths of plants ahout two-thirds grown. 



These were covered with glassine bags for three days, as in previous 

 experiments. 'The results <»f these tests ace shown in Tables III 



an. I IV. 



