VARIATION AND HEREDITY 235 



rust, and they do not bake into a good loaf. This 

 last property depends upon the amount of gluten 

 present, and it is the greater proportion of this which 

 gives to the ' hard ' foreign wheat its quality of 

 causing the loaf to rise well when baked. For some 

 time it was held that ' hard ' wheat with a high 

 glutinous content could not be grown in the English 

 climate, and undoubtedly most of the hard varieties 

 imported for trial deteriorated greatly in a very short 

 time. Professor Biffin managed to obtain a hard 

 wheat which kept its qualities when grown in England. 

 But in spite of the superior qualities of its grain from 

 the baker's point of view, its cropping capacity was 

 too low for it to be grown profitably in competition 

 with English wheats. Like the latter, it was also 

 subject to rust. Among the many varieties which 

 Professor Biffin collected and grew for observation 

 he managed to find one which was completely im- 

 mune to the attacks of the rust fungus, though in 

 other respects it had no desirable quality to recom- 

 mend it. Now as the result of an elaborate series 

 of investigations he was able to show that the 

 qualities of heavy cropping capacity, ' hardness ' 

 of grain, and immunity to rust can all be expressed 

 in terms of Mendelian factors. Having once an- 

 alyzed his material, the rest was comparatively 

 simple, and in a few years he has been able to build 

 up a strain of wheat which combines the cropping 

 capacity of the best English varieties with the hard- 

 ness of the foreign kinds, and at the same time is 

 completely immune to rust." 1 



1 Punnett, " Mendelism," Chapter XIV. 



