334 MINNESOTA STATE HORTICULTURAL SOCIETY. 



characters thereby designated withdraw or entirely disappear in the 

 hybrids, but nevertheless reappear unchanged in their progeny. It 

 is perfectly immaterial whether the dominant character belong to 

 the seed bearer or to the pollen parent, the form of the hybrid re- 

 mains identical in both cases." This interesting fact was also em- 

 phasized by Galtner with the remark that the most practical expert 

 is not in a position to determine in a hybrid which of the two paren- 

 tal species was the seed or pollen plant. The Mendelian theory is 

 that in the first generation bred from hybrids these reappear, to- 

 gether with the dominant (or prepotent) characters, also the reces- 

 sive or latent ones with the full peculiarities, and this occurs in the 

 definitely expressed average proportion of three to one, so that 

 among each four plants of this generation three display the domin- 

 ant and one the recessive. Once the hybrids resulting from re- 

 ciprocal crosses are fully formed they present no appreciable dif- 

 ference in their subsequent development, and, consequently, the re- 

 sults (of the reciprocal crosses) can be reckoned together in each 

 experiment. 



In the case of the Perkins' seedlings how shall we decide which 

 is the dominant character by the appearance and quality of the seed- 

 lings ? Under the heading of the offsprings of hybrids in which sev- 

 eral differentiating characters are associated we find this explanation : 

 "The next task consisted in ascertaining whether the law of devel- 

 opment discovered in these applied to each pair of differentiating 

 characters when several diverse characters are -united in the hybrid 

 by crossing. As regards the form of the hybrids in these crosses 

 the experiments showed throughout that this invariably more nearly 

 approaches to that one of the two parental plants which possesses 

 the greater number of dominant characters." Which, to my mind, 

 with the Perkins' seedlings, not examining the trees and other char- 

 acteristics, only judging from external appearance of the fruit, would 

 constitute the Wealthy to be the dominant character. 



Luther Burbank, who is probably one of the greatest living au- 

 thorities on plant breeding, says : "The two influences or forces 

 which control plant and animal breeding are heredity and envi- 

 ronment. To guide the interaction of these two forces is the sole 

 object of the breeder, whether of plants or of animals. A general 

 knowledge of the relations and affinities of plants is not sufficient for 

 the successful plant breeder. He must be a skillful biologist, and 

 having a definite plan must be able to correctly estimate the action 

 of the inherent and external forces which he would control. A plant 

 breeder, before attempting to make new combinations, should select 

 with great care the individual and plants which seem best adapted 

 to his purpose. This requires an exceedingly keen perception of 

 minute differences, great patience and extreme care in breeding the 

 organisms operated upon. This applies more particularly to ani- 



