the tobacco crop consists of varieties with this sort of resistance. Havana 
425 carries this resistance, and it is present in the experimental tobacco. 
Additionally, a small segment of a chromosome from N. longiflora confers 
resistance, in certain varieties, to race O of Pseudomonas syringac pv. 
tabaci (7). Over 90 percent of the commercial tobacco in Wisconsin has 
this type of resistance, in addition to resistance to tobacco mosaic virus, 
but Havana 425 and the genetically engineered tobacco to be tested in this 
proposed field test do not have this resistance. As far as is known, these 
additions to the genetic complement of tobacco had an effect only in 
regard to the response of the crop to these diseases. There is no reason to 
suppose that resistance to Agrobacterium tumefaciens in the experimental 
tobacco to be tested in this proposed field test would have any effect other 
than resistance to Agrobacterium tumefaciens . 
The crown gall disease caused by /K. tumefaciens is not known to occur in 
field tobacco. It is highly unlikely that the genetic alterations would affect 
the interactions of the experimental tobacco with other microorganisms or 
viruses. 
Environmental Assessment 
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