WHEAT, OATS, BARLEY 11 



fact that susceptibility to rust was dominant to 

 immunity to rust. 



This means that when a susceptible type of 

 wheat is crossed with an immune one, all the off- 

 spring will be susceptible. But it means also 

 that the recessive quality of immunity will 

 reappear in one-fourth of the offspring of the 

 second generation. 



And thereby hangs the tale of Professor 

 Biffen's achievement, as will appear in a moment. 



CHARACTERS THAT Do NOT "MENDELIZE" 



Before following this let us glance at the 

 other groups of unit characters which Professor 

 Biff en found not subject clearly to the rules of 

 dominance and recessiveness. 



These groups include fewer characters than 

 those in the dominant list, partly perhaps 

 because it is obviously more difficult to study 

 characters that do not show the clear phenomena 

 of dominance and recessiveness. But these 

 groups are highly interesting none the less. The 

 unit characters that showed what Professor 

 Biffen speaks of as irregular dominance as 

 studied in this investigation, were only two, 

 namely: (1) felted glumes versus glabrous 

 glumes; and (2) gray-colored glumes versus 

 red or white glumes. 



