292 Non-Isolable Races. 



sowing. They obviously offer too great a prospect of 

 a repetition of the evil. Moreover the seeds of these 

 bolters cannot, either by chance or carelessness, get mixed 

 up with those of the biennial beets because they ripen 

 a year earlier. Thus in every generation an absolutely 

 rigid selection of biennial examples as seed-parents takes 

 place, and must have taken place as long as the culture 

 of beets has proceeded on rational lines. 



Nevertheless these bolters have not disappeared. 

 Stringent selection has failed to eliminate them. More- 

 over as far as historical data enable us to decide, the 

 proportion of bolters remains about the same. In ref- 

 erence to this case at any rate we are therefore fully 

 justified in stating that selection cannot effect in the 

 course of a long period of time what it fails to bring 

 about within a few years. 



This belief is w^idely and firmly held by beet-farmers. 

 They are always in search of new means of combating 

 this evil ; but the mere selection of biennial beets is con- 

 sidered to be without prospect of success. Rimpau has 

 endeavored to attain this end by raising a triennial race, 

 by selecting the so-called laggers, i. e., plants which have 

 not flowered in the second year;^ but most agriculturists 

 content themselves with making the conditions of culture 

 as unfavorable as possible to this evil.^ 



These laggers are in a sense analogous to the bolters, 

 inasmuch as they have been eliminated by the normal 

 ]3rocess of selection since the time when beets were first 



^W. Rimpau^ Das Aufschiessen dcr RnnkcIrUhcn, Landwirtsch. 

 Jahrbiicher, Vol. V, 1876, p. 31, and Vol. IX, 1880, p. 191. By the 

 same author, Das Saniciischiesscn dcr Ruben, Deutsche Landvv. Presse, 

 Jahrg. XXI, No. 102, Dec. 22, 1894, P- 984- 



^A list of the most important papers on the subject is given by 

 RuMKER. Die Ziickcrriihenzuchtung der Gegenzvart, Blatter fiir 

 Zuckerriibenbau, 1894, PP- 22-23. 



