12 TOBACCO BREEDING. 



formity of the plants in the field and thus produce the most profit- 

 able crops. 



The variations in tobacco plants may be divided into two general 

 classes — variation in type and individual variability within the type. 

 The causes of the variations in type, or striking variations, include 

 crossing and change of soil and climatic conditions, particularly the 

 change of seed from the Tropics to temperate regions. The causes 

 of individual variations within the type include the fortuitous va- 

 riations or inherent tendency to variability, methods of soil fertili- 

 zation and cultivation, maturity of seed, and various local conditions. 

 AYith an understanding of these conditions the grower can to a great 

 extent control the degree of variability by methods of saving seed, 

 systems of cultivation, and other practical methods of culture. 



THE INTRODUCTION AND ACCLIMATIZATION OF VARIETIES. 



The introduction of the seed of standard foreign-grown varieties 

 of tobacco has been the source of increased wealth and prosperity 

 in certain tobacco districts of the United States. In other regions 

 such importations have resulted in great financial loss to the grow- 

 ers, which in most cases has been due to a lack of knowledge of the 

 effect of the change of soil and climatic conditions on the particular 

 type of tobacco grown. The writers have had an unusual opportu- 

 nitv in the course of their work to observe the behavior of crops 

 grown in different tobacco-gi^owing sections from imported seed, and 

 have conducted extensive experiments in taking seed from one dis- 

 trict to another, with a view to securing definite information on 

 this subject for the benefit of the growers. The results of these 

 observations are presented here for the guidance of tobacco growers 

 who desire to use foreign-grown seed or who wish to change their 

 seed. 



The western Florida and southern Georgia Sumatra tobacco in- 

 dustry is an illustration of the successful introduction of a foreign- 

 grown variety of tobacco. Tobacco growers in this region secured 

 small samples of the seed of the Sumatra variety of tobacco from 

 the island of Sumatra. At first small experimental crops were 

 grown and seed saved from the best plants in these crops. In the 

 course of this exj^erimental cultivation it was noticed that the 

 plants grown under the partial shade of trees in freshly cleared 

 fields produced finer and more desirable leaves for cigar wrappers 

 than the plants grown in the open. This fact led to the erection of 

 an artificial shade over the fields, made of slats laid on a suitable 

 framework. This method of growing tobacco was introduced about 

 1896 by ]Mr. D. A. Shaw, of Quincy, Fla. Later, other groATers 



96 



