PLANT HYBRIDIZATION BEFORE MENDEL 293 



« 



seed parent. This interesting fact, as Mendel states, had already 

 been observed by Gartner (4), whose statement it may be worth 

 while to reproduce. 



"This most important and most interesting phenomenon in the cross- 

 ing of plants for the production of hybrids is the complete similarity of 

 the two products ; in that seeds which come from the one as well as 

 from the other fertilization give rise to plants of the most complete 

 similarity ; so that the dissimilar origin and derivation of the two kinds 

 of hybrids, after the most careful investigation with respect to their 

 form and type, does not admit of the slightest distinction between them, 

 and even the most practised expert with a hybrid species is not in a 

 position to distinguish the origin of the hybrid with respect to the sex 

 of the parents. . . . This is the general rule with almost all plants." 

 (p. 223.) 



Here it is well to call attention to the fact that Mendel never 

 for a moment considered, as did all the older hybridizers, that 

 he was crossing one individual as a whole with another as a 

 whole, but that he was pitting one character in an individual 

 against a single contrasting character in another individual. 

 Herein is revealed Mendel's scientific genius and analytical in- 

 sight. 



In the seven classes of "character-crosses," if we may so desig- 

 nate them, that Mendel made with peas, he found that in the 

 first generation, the following characters were dominant. 



Dominant Recessive 



1. round seeds over wrinkled seeds • 



2. yellow seeds " green seeds 



3. gi^ey or brown seed-coats " white (i.e., colorless) seed-coats 



4. inflated ripe pods " constricted ripe pods 



5. immature green pods *' immature yellow pods 



6. axial arrangement of " bunched or terminal arrangement 

 flowers of flowers 



7. tall stems ** dwarf stems 



Of these "characters," those relating to the shape and color of 

 the seeds (i.e., of the cotyledons within the seed-coats) can, of 

 course, be seen at once after the flowers have been fertilized, and 

 the seeds grown. All of the other characters, of seed coats, pods, 

 flowers and stems, can only, of course, become apparent when the 

 hybrid seedlings grow up and produce stems, flowers, pods, and 

 seeds themselves. 



Mendel now proceeds with the study of the second generation 

 (F2). Of the self-fertilized hybrid he says: 



