168 BREEDING CROP PLANTS 



1910 to 1914 inclusive. An average of 150 plants was carefully 

 examined yearly and no aberrant types were observed. 



In 1912 about 100 acres were grown by the Windsor Tobacco 

 Growers' Corporation from seed saved in 1911, and late in the 

 season three plants were discovered which had produced a high 

 leaf number and showed no signs of blossoming. One of these 

 plants when taken to the Connecticut Experiment Station green- 

 house produced 72 leaves and blossomed about January first. 

 Considerable seed was saved from this plant and one-third acre 

 of the new type was grown in 1913. The plants were of uniform 

 appearance. They differed from the normal Cuban in having 

 leaves of a somewhat lighter green, in having but few basal 

 suckers, and in a long continued period of growth; whereas 

 the normal Cuban variety bears a terminal inflorescence 

 after producing from 14 to 25 leaves on the main stem. 

 From 25 to 30 acres have been grown yearly by the same tobacco 

 company. The quality and yield of this giant variety which has 

 been named Stewart Cuban, have been quite satisfactory. One of 

 the great difficulties of growing these giant forms is the extra 

 trouble of obtaining seed. This difficulty has been overcome in 

 part by studies which show that a reduction of length of day leads 

 to the production of blossoms. These studies will be briefly de- 

 scribed after giving a short history of the Maryland Mammoth 

 type. 



The Maryland Narrowleaf Mammoth type first appeared in 

 1907 in the second generation of a cross between two common 

 varieties of Maryland tobacco (Garner, 1912). One hundred 

 and fifty-seven plants of this new form were grown in 1908 and 

 all plants were of mammoth habit. This new variety has been 

 grown commercially since that time and retains its characteristics 

 of high leaf number and non-blooming habit under normal field 

 conditions. 1 Accurate information regarding the acreage of 

 Mammoth tobacco in southern Maryland is not available but 

 some hundreds of acres were grown in 1920. The chief limiting 

 factor in the acreage is the quantity of seed available. As Mary- 

 land tobacco is harvested by cutting and spearing the stalk, 

 there is little additional cost in harvesting the giant type. The 

 Mammoth variety will yield 2,000 Ib. or more per acre and the 



1 Information kindly furnished by DR. W. W. GARNER, Physiologist, 

 in Charge of Tobacco and Plant Nutrition Investigations, B. P. I., United 

 States Department of Agriculture. 



