128 JOOKNAL OF THE ROYAL HOiiTiCULTUUAL SOCIETY. 



Ill view of the adoption of the *' presence and absence " method, 

 which in the circumstances seems inevitable, the question naturally 

 arises whether it is quite expedient to retain for general use the Men- 

 delian terms " dominant " and " recessive." If these terms are applied 

 in the original sense, as they usually are, to the " dominance " of a 

 higher unit-factor over a lower unit-factor, then from the standpoint 

 of " presence and absence " the application is unsound. While, on 

 the other hand, if the terms are more properly restricted to the " pre- 

 sence " and " absence " of a single unit-factor it is to be feared that 

 considerable confusion must arise. 



On the whole, therefore, it would seem better to use the terms 

 " liigher " and " lower " (" epistatic " and " hypostatic " of Bateson) 

 in place of " dominant " and " recessive," where two unit-factors are 

 concerned. 



Application of Mendel's Law to Hokticultube. 



Eecent experiments have shown that many simple characters in 

 garden plants follow^ Mendel's law. When the unit-factors happen to 

 correspond with the horticultural characters, it is a simple matter 

 for the breeder to breed quickly what he wants; for he knows that, 

 according to Mendel's law, the plant manifesting the lower factor will 

 breed true at once, and that by breeding from several individuals 

 manifesting the higher factor one will be found which breeds true. This 

 enables the breeder to dispense entirely with the old and laborious 

 method of so-called " fixing " by continuous selection, which method, 

 though usually effective in the end, is now clearly recognized as a waste 

 of time. 



Mendel's law provides a much quicker and more effective method 

 of achieving the same result. Mendel's metnod was simply to breed 

 from single individuals separately. By so doing the breeder can select 

 the particular individual which breeds true in accordance with his 

 requirements and increase his stock solely from that source. In that 

 way the grower secures at once a true and permanent stock, whi(^ii 

 can be maintained simply by isolation. 



Beeeding Novelties by Ee-combination. 



The combination of two pairs of simple characters by crossing, and 

 the results which follow the self-fertilization of such crosses, are of 

 great utility to the breeder, for in the process of re-combination following 

 Mendelian segregation new forms arise which will breed true in accord- 

 ance with Mendel's law. Thus, Mendel himself crossed a round yellow 

 with a wrinkled green pea, and obtained in the second generation two 

 new forms — round green and wrinkled yellow peas, some of which 

 bred true at once in accordance with his law. 



By following Mendel's law Me. W. Cuthbeetson, the well-known 

 grower of sweet peas, states that he obtained in the second generation 

 a true stock of the new and valuable variety, ' Waved King Edward,' 

 by simply crossing the plain red ' King Edward ' with the waved 



