How Domestic Varieties Originate 229 



ful influences. If they can be brought through the early 

 period of growth and become well established, and the 

 foliage or fruit is not attacked by rots or blights, the 

 grower will usually be rewarded by an earlier and more 

 abundant crop of slightly smaller and less firm fruit. 

 These characters will be more slightly emphasized in sub- 

 sequent years by continuous seed propagation." Goff 

 remarks that the increase in earliness in tomatoes, fol- 

 lowing the use of markedly immature seeds, "is accom- 

 panied by a marked decrease in the vigor of the plant, and 

 in the size, firmness, and keeping quality of the fruit." 

 These results are probably closely associated with the 

 chemical constitution and content of the immature seeds. 

 The organic compounds have probably not yet reached 

 a state of stability, and therefore they respond quickly 

 to external stimuli when placed in conditions suitable to 

 germination ; and there is little food for nourishment of 

 the plant let. The consequent weakness of the plant let 

 results in a loss of vegetative vigor, which is earliness. 

 (See Rule 2.) 



Still another feature connected with the choice of seeds 

 is the fact that in some plants, as in various Ipomceas, for 

 example, the color of the seed is more or less intimately 

 associated 'with the color of the flower which produced 

 them and also with the color of the flower which they 

 will produce. 



6. Plants that have any desired characteristics in 

 common may differ widely in their ability to transmit 

 these characters. It is usually impossible for the cul- 

 tivator to determine, from the appearance of any given 

 progeny, which is the most unvariable and the most like 



