WHITH BURLEY TOBACCO RESISTANT TO ROOT-ROT. ~ a 
in some northern districts tobacco has been given a definite and per- 
manent place in rotation with other farm crops. 
DEVELOPMENT OF BURLEY STRAINS RESISTANT TO ROOT-ROT. 
Although a high measure of control of the root-rot.in the Burley 
section is attained by the system of rotation in use it is evident 
that, on account of the extreme susceptibility of the Burley variety, 
considerable disease occurs annually. The susceptibility of this 
variety not only prevents continued culture when desired, but also 
makes the growing of second and third crops on the soil quite a 
game of chance. A type of Burley as resistant as some of the cigar 
varieties and still possessing the yield and quality of the ordinary 
Burley strains therefore would be extremely valuable in reducing 
the annual loss from disease. Two possible means of producing such 
a type are selection for disease resistance among commercial varie- 
ties now grown and crossing resistant green types, such as some of 
the cigar tobaccos, with White Burley, for the purpose of adding 
disease resistance to the White Burley characteristics. The first 
method, that is, selection for resistant strains in diseased fields, has 
been resorted to in obtaining the results presented here, All tobacco 
growers have seen fields in which the crop has made a very uneven 
growth, though all the plants apparently had an equal chance to 
start and develop. It sometimes happens that these fields behave in 
this manner because of the presence of the root-rot and the use of 
impure seed. Those plants which grow rapidly and stand out dis- 
tinctly from their neighbors may be resistant to the disease. A 
large number of these have been selected and the seeds saved from 
the individual plants and grown in separate rows on sick soils the 
following year. A few of these selections have shown very distinct 
resistance when compared with ordinary Burley, and these strains 
propagated and tested over a period of several years under many 
varied conditions have continued to maintain their original degree 
of resistance. In some cases these strains have been tested on a 
rather large scale on both healthy and sick soils for the purpose of 
comparing the quality of the cured leaf produced with that of the 
ordinary White Burley. The results on the whole have been very 
encouraging, although the ideal in mind has not yet been reached. 
The resistant strains thus far produced and given commercial trial 
are all of the drooping-leaf type and not stand-up Burleys, which 
many growers prefer. Encouraging results have now been secured 
in developing resistance in the stand-up types also, and it is expected 
that these strains will soon be ready for testing commercially. 
A more important feature, however, is the quality of the resistant 
Burleys obtained, as compared with the best strains of ordinary 
