TOBACCO RESISTANT TO BLACK ROOT ROT 



capacity of the progeny of the various crosses with corresponding properties of 

 the controls, it was possible to estimate their comparative acceptability in these 

 respects. 



The progeny- of plants selected as being satisfactorily' resistant to black root 

 rot in the foregoing tests were further tested under conditions unfavorable to 

 the development of the disease and otherwise favorable for the growth and 

 development of tobacco, to determine their value under favorable growing con- 

 ditions. The controls in these tests were strains of regular Havana Seed known 

 to be highly acceptable in type, qualit>-, and yielding capacity under favorable 

 tobacco producing conditions. The most acceptable plants were selected for 

 further use in the project. 



The progeny of these latest selections were retested simultaneously under 

 lilack root rot promoting conditions and under conditions favorable to the good 

 growth and development of tobacco, to make certain of their acceptability both 

 for resistance to black root rot and for type, qualitx-, and yielding capacit>', so 

 far as these properties could be ascertained in small plot tests. The controls 

 used were the same strains that had been used previously. 



3. The third phase was the commercial testing of the strains to determine 

 their acceptability to tobacco farmers and to buyers and users of Connecticut 

 Valley Havana Seed tobacco. For these purposes the strains were placed with 

 enough tobacco farmers and were grown in sufficient amounts to provide a fair 

 demonstration of their productiveness and salability. Those strains which, as a 

 result of these trials, seemed to be suitable for wider use under Connecticut \'alley 

 conditions, were distributed to farmers. 



Results of the Breeding Phase of the Work 



Numerous as were the strains of regular Havana Seed that were tested in 

 search of resistant specimens, the new strains which were produced by controlled 

 breeding procedures, partly here and partly elsewhere but all developed here, 

 were even more numerous. 



Two of the new strains seemed to be sufficiently acceptable to both farmers 

 and buyers to warrant their continuation. These are Havana 211 and a newer 

 strain Havana K2. Although' Havana 211 has not been fully accepted on the 

 quality basis by all of the tobacco trade, it is now being bought in large quantities 

 by our leading tobacco dealers and cigar manufacturers. The strain has become 

 well established in the tobacco culture of the Connecticut Valley. Although 

 I lavana K2 has not been tested long enough commercially to prove its entire 

 suitability, it is, nevertheless, very promising. At the present time it seems to be 

 largely acceptable to tobacco farmers and to the tobacco trade, alike. 



Havana 211 (see figure 1) was produced as a result of cooperative tobacco 

 breeding work in the Connecticut Valley and in Wisconsin. The strain was bred 

 in Wisconsin; it was developed and distributed to tobacco farmers first in the 

 Connecticut Valley. The original cross (5,7) from which it was developed was a 

 cross of Page's Comstock and Havana 38. Page's Comstock was resistant to 

 black root rot, but it was coarseh' typed and largely- unacceptable in qualit}'. 

 Havana 38 was an improved strain of regular Havana Seed, highh' acceptable 

 in t\pe and qualit>-. 



