2i8 MENDELISM 



this quality of strength, are worth in England some 

 shillings a quarter more than home-grown wheats. 



When such strong American varieties are grown in 

 this country the majority of them are rapidly found to 

 lose this quality, and to become after a short time as 

 ' weak ' as ordinary English wheats. Some of them do, 

 however, retain their strength, and after several seasons 

 in one case fourteen show no signs of deterioration. 

 An example of a wheat of this latter type is afforded 

 by Red Fife, which is the basis of the mixed wheat 

 known commercially as Manitoba Hard, the latter 

 consisting, as a matter of fact, of a mixture of several 

 different varieties. Unfortunately these permanently 

 hard wheats do not yield so large a crop as the com- 

 monly cultivated English varieties, and so their higher 

 price does not make up for the smaller number of 

 bushels per acre obtained when they are grown. 



Biffen therefore set to work upon the problem of 

 combining hardness or strength with the power of 

 yielding a good crop, and with the other desirable 

 qualities characteristic of the home-grown varieties. 

 With this end in view Manitoba Hard was crossed with 

 a typical English wheat Rough Chaff. 



The F x plants produced grains all of which were 

 fully as hard as those of the Manitoba variety. 



These grains were sown, and it was found that some 

 of the resulting plants produced strong grains and 

 others weak ones, and that the former were to the 

 latter very nearly in the numerical ratio of 3:1. 

 Actually they were as 152 : 48 in a sample of 200 

 taken at random. 



