lyo PLANT HYBRIDIZATION BEFORE MENDEL 



"Among the characters of hybrids worthy of recommendation for agri- 

 culture, their tendency toward luxuriance in the stalks and leaves, and 

 their extraordinary capacity for tillering, is related above. With respect 

 to the raising of forage, agriculture could, without doubt, make great 

 use of this characteristic." (p. 634.) 



Gartner derived, from his long experience, a certain, philosophy 

 concerning the nature of hybrids which is noteworthy. He recog- 

 nized an inequality in the influence of the relative "potency," as 

 he termed it, of one parent over another in a cross ; which potency 

 was maintained whichever way the cross was made. As now inter- 

 preted it probably means the relative dominance of one or more 

 factors of the respective parents. Gartner, not having the knowl- 

 edge which has come in consequence of Mendel's investigations, 

 sought a theoretical explanation for this phenomenon of domi- 

 nance and gave it the designation "sexual affinity" {W ahlverwand- 

 schaft) in the crossing of species, the magnitude of which he con- 

 sidered could be measured by the number of viable seeds produced 

 in the cross. He seems to confuse the matter by appearing to indi- 

 cate that there might possibly be a different number of seeds pro- 

 duced by the reciprocals of reciprocal crosses, thus presumably 

 indicating a possible "prepotency," so called, of one of the parents 

 in the cross. In other cases he seems to mean simply the relative 

 influence, so to speak, of such and such species when crossed with 

 others. This appears to be the meaning in the following : 



"This manifestation of generic types, according to which one species 

 operates in a predominant manner over several other species in hybrid 

 breeding, is a further incontrovertible proof that the relationship of the 

 forces, through which the union of two pure species takes place, must 

 be unlike, and that thereby there can be no question of any balance of 

 factors." (2f, p. 290.) 



It will be seen that Gartner's view of hybridization was that 

 "species" was crossed with "species" as such, each species as a 

 whole exerting its own relative power or "potency" in the cross — 

 the hybrid being regarded as the resultant, so to speak, of the 

 contest for supremacy of the two competing natures in the com- 

 pound. This view is well enough expressed in the following pas- 

 sages : 



"Thus, just as there are species in a natural genus, which possess a 

 prepotent fertilizing power upon several other species of their genus, so 

 there are also species which exert upon several others such a typical pre- 

 dominating effect, not to an equal extent to be sure, but still of such a 



