ANNUAL REPORT, 1933 



15 



Strain of 



Havana Seed 



Tobacco 



Common strain , 



Grown on land free or 

 nearly free of 

 Thiflavia basicola 



Grown on land heavily 



infested with 



Thielavia basicola 



Yields Grade 



per Acre Index 

 Pounds 



2098 



142A3 2367 



.419 

 .440 



Crop 

 Index 



879 



1042 



Yields Grade 



per /Vcre Index 

 Pounds 



1268 

 1991 



.256 

 .349 



Crop 

 Index 



325 

 695 



New strains 



NOTE: Grade Index is a number expressing the grading quality of tobacco produced by a strain 

 in an experiment. It is based upon the percentage yield of grades, and the percentage relation- 

 ships of these difTerent grades, as given below: 



Light wrappers 1.00 



Medium wrappers 60 



Long seconds (19" & longer) 60 



Short Seconds (17" & shorter) 30 



Long darks (19" & longer) 30 



Dark stemming (17" & shorter) 20 



Fillers 10 



Brokes 10 



Grade Index is derived by multiplying the percentage yield of each grade by its respective per- 

 centage relationship in the above schedule and adding the products. 



Crop Index is a number expressing crop value. It is derived by multiplying the total acre 

 production of tobacco in pounds by the Grade Index value of that particular lot of tobacco. 



Grade Index, Crop Index, and the adopted price relationships given above do not necessarily 

 represent commercial values and prices. 



Some of these resistant strains deserve testing on a considerably greater scale 

 in numerous places in the Connecticut Valley, to determine their excellence in 

 practical production. One strain was so tested in 1933 and proved to be highly 

 satisfactory that season. Arrangements have been made for such testing of 

 several of these strains in 1934. 



DEPARTMENT OF BACTERIOLOGY 



Leon A. Bradley in Charge 



Application of the Azotobacter Soil Plaque Test for Determining Mineral 

 Deficiencies in Massachusetts Soils. (J. E. Fuller.) Further studies have 

 been made on plots previously investigated, and several new plots have been 

 added. In all instances the Azotobacter test indicated a deficiency of available 

 phosphorus even though satisfactory crops were grown on all of the plots rep- 

 resented. The results obtained from the tests agreed with those reported by 

 several other investigators, and with those previously reported from this Station 

 (Bulletin 293, p. 14). Tests by Truog's method indicated that the soils studied, 

 with few exceptions, contained sufficient available phosphorus for crop growth. 

 Perhaps some factor in the technique of the Azotobacter test may have been re- 

 sponsible for rendering the phosphorus in the soil unavailable for Azotobacter 



