Varieties of Roots. 



147 



Improvement of mangels: 



The first means used in the improvement of the beet was giving the 

 plant a better environment, — fertiUzing and cultivating the soil, amelior- 

 ating the moisture and temperature conditions. This induced greater 

 variation in the plants, and those plants showing characters considered to 

 be of value were selected for seed production. Modification of the en- 

 vironment is still an important factor in inducing variation. Selections 

 were made from time to time for such characters as greater size and 

 thickness of the root ; regularity of form ; color ; amount of the root be- 

 low the surface of the ground ; 

 and in the case of mangels, selec- 

 tion for these external charac- 

 teristics seems to have been the 

 only selection which has been 

 given until very recently. 



Until 1850, no other meth- 

 ods were used in the selection 

 of " mother " beets of either 

 mangels or sugar-beets, but 

 about this time it became evident 

 that varieties of mangels, like 

 varieties of sugar-beets, were 

 not of equal value. Anderson 

 of Scotland, 1830, found that 

 three varieties of mangels which 

 he analyzed varied widely in 

 composition. Dubrunfaut in 

 1825 and others insisted that 

 some method for determining 

 amount of sugar in the beet 

 should be worked out, and again 

 in 1850 Ventzke pointed out that sugar-beet growers were selecting 

 " mother " beets for non-essentials, as external characters, and neglecting 

 this important thing, sugar. During this interval considerable thought 

 was bestowed on the problem, and Vilmorin in the same year (1850) 

 began selecting by means of specific gravity determinations, assuming 

 that roots of the highest specific gravity would be of the most value. 

 This he soon abandoned, and, although it is still employed by some seed- 

 growers in Europe, selection was made by testing the specific gravity of 

 the juice. The interest shown in the topic can be realized from the fact 

 that Vilmorin read three papers on the subject in the years 1850, 1851 

 and 1856, In 1867 Scheibler pointed out that this latter method was 



Fig. 57. — Scarlet intermediate. A good 

 carrot for table tise, but the seeds do not 

 germinate well under field conditions. 

 Its yield is small, and the growth slow. 



