13 



of the Magnum Bomim, was also highly successful ; 

 many others might be mentioned who have done good 

 work on systematic lines. To be successful in crossing 

 it is necessary that the experimenter should be tho- 

 roughly acquainted with the features of the potatoes 

 he is treating with. The mere knowledge that they 

 have proved profitable in cultivation is not sufficient, 

 although it is a good groundwork to start upon. The 

 breeding of these varieties must be known, so that they 

 may be mated to neutralise weaknesses and develop 

 the better features contained in them. Varieties the 

 result of crossings often possess latent characteristics 

 which are brought into prominence when they are mated 

 with other suitable varieties. To be successful in 

 variety-making it is important that the experimenter 

 should possess an innate acquaintance with all features 

 of the potatoes he is going to deal with, otherwise 

 much of his labour will be futile. 



Points to Develop in the Production of New 

 Varieties. 



The points which it is most important to en- 

 deavour to develop are vigour, power of resisting 

 disease, and quality. Without vigour the new variety 

 will soon become unprofitable, as the yield will be 

 small, and the plant will quickly succumb to the 

 diseases which are lying wait for it. Robustness is 

 indicative of disease-resisting properties, but not 

 entirely so, and it is necessary to use as much as 

 possible varieties which have proved themselves disease- 



