ANNUAL REPORT, 1937 



21 



Seed comparatively by means of well-arranged, small plot experimental tests 

 and to select the most promising strains for further and more extensive testing; 



(2) to conduct the more extensive tests cooperatively with successful tobacco 

 farmers and with cigar manufacturers, to learn the merits of the strains in practical 

 production and commercial uses, and to obtain the criticisms of these men and 

 also their suggestions for the improvement of the strains from their point of view; 



(3) to improve the strains, if possible, by further selection and breeding, to 

 correct the faults which were detected in the previous cooperative tests; (4) to 

 conduct further cooperative tests with successful tobacco farmers and with cigar 

 manufacturers to obtain, if possible, their approval of the strains. 



The results of the first phase of the work were promising. They have been given 

 in previous reports. The complete results of the second phase of the work have 

 not been learned, but the portion of these results that are known are also promis- 

 ing. They have shown the strains to possess merit, but to need improvement in 

 certain respects in order to be entirely acceptable from the point of view of the 

 cigar manufacturers. As a result, the project is now in its third phase of the 

 proposed procedure. 



Reductions in Yield and Quality of Tobacco Caused by Mosaic. (C. V. Kight- 

 linger.) Experiments were begun in 1936 to make comparative determinations 

 of reductions in yield and quality of Havana Seed tobacco caused by common 

 tobacco mosaic whose periods of infection were inoculated for at successive 15-day 

 intervals, extending from as soon after time of setting to as near topping time as 

 conditions would permit. Uniform conditions of culture, harvesting, and curing 

 of the tobacco were employed. 



The tobacco for these experiments was set June 5 and was harvested August 23. 

 Topping was done August 5. The inoculations for mosaic were made artificially 

 by rubbing the leaves of the plant to be inoculated with expressed juice of mosaic 

 diseased tobacco plants. The dates of inoculation were June 10, June 25, July 10, 

 and July 25. Two replications of the experiment were made. 



The average experimental results obtained in 1936 are as follows: 



Dates 



of 



Inoculation 



Control 1 



June 10 



June 25 



Control 2 



July 10 



July 25 



Control 3 



.Average Yield 

 per acre 

 (pounds) 



1991 



1545 



1624 



2006 



1709 



1840 



2035 



Average 

 Grade 

 Index 



.395 

 .322 

 .336 

 .393 

 .348 

 .372 

 .402 



Average 

 Crop 

 Index 



786 

 497 

 546 

 788 

 594 

 684 

 818 



Grade index, as used here, is a number expressing the grading quality of tobacco produced under 

 the conditions of the experiment. It is based upon the percentage yield of each grade of tobacco 

 and the relative values of these grades given below: 



Lights 1.00 Long darks (19" and longer) 30 



Mediums 60 Dark stemming (17" and shorter) 20 



Long seconds (19" and longer) 60 Brokes 10 



Short seconds (17" and shorter) 30 Fillers 10 



The grade index is derived by multiplying the percentage of each grade of tobacco by the re- 

 spective rating of the grades, given above, and adding the products. 



Crop index, as used here, is a number expressing the crop value of tobacco produced under the 

 conditions of experiment. It is based upon the gross yields of tobacco in pounds per acre and the 

 grade index of the tobacco. Crop index is derived by multiplying the gross yield of tobacco in 

 pounds per acre by the grade index of the tobacco. 



Grade index and crop index and the adopted relative values of the different grades of tobacco, 

 as used here, do not necessarily represent current commercial prices of tobacco. 



