43 
of INA + bacteria is in snowmaking, to enhance the skiing season either in 
spring or fall. No public information is available on the strains used or 
the properties of these strains, nor the quantities employed in snowmaking. 
Dr. Tolin concurred with Dr. Vidaver. She said the practices outlined in 
the AGS proposal are consistent with USDA practices, and she supported 
approval of the project with the five stipulations suggested by Dr. Vidaver. 
Dr. Fedoroff also supported Dr. Vidaver' s recommendation. 
Dr. Pirone said he agreed with Dr. Vidaver' s analysis but requested addi- 
tional information on the methodology of pathogenicity testing. Dr. Lacy 
also said he would like AGS to provide more information about the methods 
and results of pathogenicity testing. As he is familiar with Pseudomonas 
syringae , he did not, however, believe emission of pathogenicity testing 
data was critical in his evaluation of the AGS proposal. He pointed out 
that the proposed test site is geographically isolated from all major 
production areas of the test plant species. Crops grown in the vicinity 
of the test sites are primarily potato and alfalfa; no known isolates of 
Pseudomonas syringae are pathogenic to potato, alfalfa, or the test plant 
species . 
Dr . Vidaver explained that some strains of Pseudomonas syringae are patho- 
genic. The majority of these pathogenic strains are considered minor 
pathogens, occasionally important locally but generally relatively insig- 
nificant. Dr. Vidaver said AGS in greenhouse trials tested their modified 
strain for pathogenicity under conditions where adverse effects to plants 
would have been detected. However, without field trials one cannot say 
unequivocally the strain would have no adverse effect on plants in the 
field. This is one reason field testing is necessary. 
Dr. Rapp asked if AGS proposed to obtain a baseline sample of naturally 
occurring INA“ and INA + Pseudomonas syringae before spraying their modified 
strain in the test field. He also asked what would be the expected recom- 
bination frequency for Pseudomonas syringae in the field. Dr. Vidaver 
replied AGS had not proposed to obtain a baseline sample for naturally- 
occurring INA + and INA” bacteria in the field before application of the 
modified strain. 
In reply to the second of Dr. Rapp's questions. Dr. Lacy said Pseudomonas 
syringae pathovars under ideal laboratory conditions have a recombination 
frequency of lCT^ to 10”9. In the field, however, these organisms tend to 
be isolated on plant surfaces in microcolonies; recombination frequency 
in the field would be expected to be much lower. 
Dr. Lacy said he felt the AGS proposal with Dr. Vidaver 's five stipulations 
and a requirement for additional pathogenicity data should be approved for 
several reasons: (1) The experiment is important; warm temperature frost 
damage causes hundreds of millions, if not billions of dollars loss yearly 
to crops in the U.S.; (2) No new genes are being introduced into the envi- 
ronment; (3) In this proposal, a very small portion of a gencme (about 
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