P.REEDIXG RFSISTAXT VAkll-rriKS. 53 



VV. A. Orton: It is necessary to grow crops on infected land in order to make 

 selections. 



S. Fraser: To maintain tlie immunity? \V. A. Orton: 1 ilon't think so. 



S. Fraser: If grown on other free land for a series of years will it then be resistant? 



W. A. Orton: Except in this way, that if planted on infected land the non-re- 

 sistant plants can be weeded out, while if grown on non-infected land they would not 

 be noticed. 



S. Fraser: Could you mention any variety of potatoes that is resistant? 



W. A. Orton: I could not just now. I have that information in my notes, but 

 I don't recall any variety resistant to ground rot. 



The Chair: The subject treated by Professor Orton is one of very great economic 

 importance, and we can only hope that the experiments will go on and very effective 

 results be obtained. I am sure that there are opportunities in many fields for experi- 

 mentation in this line of selection, and it is something that we can almost any of us 

 ill and do it with a hope, after hearing this paper, of satisfactory result. 



