TOBACCO RESISTANT TO BLACK ROOT ROT 



15 



Discussion of Results 



The suitabilit\- of any strain of tobacco for general commercial growing de- 

 pends principally upon the ability of the strain to produce sufficient readily 

 salable tobacco to be profitable to the producer. To be readily salable, tobacco 

 must be of a quality that is acceptable to buyers. 



So far as gross yields are concerned, it is natural for farmers to want to produce 

 as much readih" salable tobacco as they can. There is a limit, however, to the 

 size of tobacco that can be handled and cured successfully with the equipment 

 available. Rather than attempt to formulate an arbitrary standard for profitable 

 gross yields, it seemed advisable to use the actual gross yielding capacity of 

 Havana 142 under black root rot promoting conditions and of regular Havana 

 Seed under favorable producing conditions as standards. So far as gross yields 

 are concerned, Havana 142 has long been acceptable under root rot promoting 

 conditions, and regular Havana Seed is largely acceptable under favorable con- 

 ditions when black root rot is not an important factor. 



The following analysis of data in Tables 3 and 4 shows how Havana 211 and 

 Havana K2 compare with the controls in productiveness under different condi- 

 tions. 



Strain 



Percent Increase over 

 Regular Havana Seed 



Yield 



Grade 

 Index 



Crop 

 Index 



Percent Inciea^e over 

 Havana 142 



Yield 



Grade 

 Index 



Crop 

 Index 



Havana 211 

 (Table 3) 

 (Table 4) 



Havana K2 

 (Table 4) 



1. Under Black Root Rot Promoting Conditions 



47 



32 

 16 



88 

 63 



4 



4.5 



33.5 II 48 0.8 



!!. Under Favorable Producing Conditions 



12 



5.5 

 0.9 



17 



10 



1.7 



.05 



5.5 



Since Havana 211 and Havana K2 equaled or e.xceeded Havana 142 slightly in 

 gross yielding capacity under black root rot promoting conditions, and e.xceeded 

 regular Havana Seed considerabK- under favorable tobacco producing condi- 

 tions, it would seem that there can be little if an>- doubt about their acceptability 

 in productiveness under most, if not all, circumstances in the Connecticut Valley. 

 Since the productiveness of these strains under black root rot conditions depends 

 largely upon their resistance to the disease, it would seem that there can be little 

 doubt about their being satisfactorilv resistant under most circumstances. 



