58 



TOBACCO BEEEDIXG. 



make a healthier, more strudy, and stronger growth, and produce 

 much better plants in the end. The comparative size, production, 

 earliness. and other characters of plants raised from light and heavy 

 seed are shown in Plate IX. figure 1. It frequently happens that the 

 light seed are the first to germinate, and in some cases the young 

 plants from the light seed are first to reach the proper stage for 

 transplanting. However, after they are about half grown they show 

 freaky tendencies and are very susceptible to various diseases, are un- 

 stable, and of little value to the tobacco grower. They sometimes 



bloom earlier and mature before the 

 average well-developed tobacco plants 

 in the field, but are deficient in yield 

 and other important qualities Such 

 plants are. of course, undesirable from 

 every standpoint and should be elimi- 

 nated before being transplanted to the 

 field, so as to give place to vigorous 

 plants grown from heavy seed. 



It is almost impossible to select and 

 discard in the seed bed the weak 

 plants produced from light seed, so 

 that it must be done, if at all, before 

 the seed is sown. Doctor Trabut, in 

 his experiments with tobacco, sought 

 to make a separation of tobacco seed 

 according to different degrees of spe- 

 cific gravity by throwing the seed 

 upon water and discarding those that 

 continued to float after a certain length 

 of time. This process effects a par- 

 tial separation, but it is incomplete. 

 The extremely small size of tobacco 

 seed makes this method rather im- 

 practicable, for the reason that minute 

 air bubbles will adhere to the seed for a considerable time and hold 

 many of the heavy seed on the surface, while some of the lighter 

 ones will lose the air bubbles first and sink to the bottom with the 

 heavy seed. Notwithstanding the incompleteness of this method. 

 Doctor Trabut found a great difference in the growth and productive- 

 ness of the seed which sank to the bottom of the vessel first, and he 

 brought to light new and vital facts regarding the importance of 

 using heavy seed. 



In order to secure a more complete separation of the light from the 

 heavy grade of seed, the writers have devised a simple and practical 



96 



Fig. 8. — Tobacco seed separator. This ap- 

 paratus separates the light, immature, 

 and poor seed from the heavy seed, and 

 can be so regulated as to furnish any 

 degree of fineness of separation desired. 

 It is now being used extensively by to- 

 bacco growers. 



