24 TOBACCO BREEDING. 



the present time showing the behavior of plants raised from arti- 

 ficially cross-fertilized seed within the variety in comparison with 

 plants raised from self-fertilized seed. The principal object of this 

 work has been the achievement of practical results, so that the 

 opportunity for scientific observations and experiments has been 

 necessarily limited. However, the writers have had the privilege 

 of making careful observations on the results of saving seed from 

 plants grown under large field tents and comparing the plants raised 

 from such seed with the plants raised from self-fertilized seed. 

 Under these tents there is little opportunity for cross-fertilization 

 with other varieties, except thru the small doors opening into these 

 tents, which are kept closed all of the time when persons or teams 

 are not actually passing thru them, so that there is little likelihood 

 of bees or other insects passing in and out. The probability is that 

 the cross-fertilization that takes place is wholly between the plants 

 saved for seed in these tents or with other plants under these shades 

 that are in bloom at the proper time for cross-pollination. 



The comparison of the plants raised from seed saved under these 

 field tents and exposed to cross-fertilization with the surrounding 

 plants and of j^lants of the same variety raised from seed protected 

 from cross-fertilization by paper bags shows that self-fertilized 

 seed produces more uniform, vigorous, and productive plants than 

 the open- fertilized seed, which is to a greater or less extent cross-fer- 

 tilized between plants of the same variety. 



It appears that the cross-fertilization of tobacco seed, even tho it 

 occurs between good individuals, has a tendency to seriously break 

 up the type. Along with the variability of type induced by cross- 

 fertilization, it frequently happens that many freak plants resembling 

 the wild species appear; these can only be explained with our present 

 knowledge of the subject as reversions. Such freak plants are not 

 usable for profitable manufacture, and consequently are a source of 

 loss to the growers. 



The size and weight of seed from the inbred plants are equal to 

 and in most cases greater than the seed saved from open-fertilized 

 plants. In a series of comparative tests of the two kinds of seed 

 in the case of four varieties grown in the Connecticut Valley it was 

 found that the inbred seed was heavier and larger than the cross- 

 fertilized seed. The total quantity of seed harvested from the 

 open-fertilized plants usually exceeded that of the inbred plants. 

 This was due to the fact that in the case of the inbred plants more 

 of the seed-bearing branches were removed than where the plants 

 were allowed to set seed under natural conditions, in order to adapt 

 the seed head for the best possible development under the paper 

 bags. Where an equal number of seed pods was examined for 



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