PLANT BREEDING 345 

Fig. 1. CASTRATION OF BuDS or Nicotiana tabacum BEFORE CROSSING. 4a, correct 
stage for castration; b, method of slitting the corolla; c, castrated bud. 
The theory supposes that when a dominant and a recessive char- 
acter meet in a cross, the germ cells which are produced in the hybrid 
do not blend these characters, but possess either the one or the other; 
and as the possession of either character is a matter of chance, on the 
average 50 per cent. will bear the dominant and 50 per cent. will bear 
the recessive character. In a plant, for example, 50 per cent. of the 
pollen cells would bear the dominant and the other 50 per cent. would 

Fic. 2. CASTRATED Bub or Impatiens sultant SHOWING METHOD OF PROTECTION IN 
GREENHOUSE WORK. 
VOL. LXXVIiI.—24. 
