HOW TO IMPROVE PLANTS 



8 9 



keep on planting the peas from the longest and most 

 slender pods, we shall by and by have a variety of which 

 the pods will be much longer and more slender than those 

 of common peas. Thus we can change a variety of plant 

 by planting year after year the seeds from only those 

 plants that shozv sonic definite variation in a marked 

 degree. 



Improvement by Selection. Figure 48 shows the re- 

 sult that has come from saving seeds of the sugar beet 



FIG. 48. Per cent of sugar in beets. 



from only those plants that had the most sugar in the 

 juice. When the beet was first used for making sugar, 

 the juice from the sweetest beets had only about eight 

 per cent of sugar in it (Figure 48, a) ; but, by testing 

 the juice of every root, and saving for seed only those 

 of which the juice contained the most sugar, the amount 

 of sugar has slowly been increased until now the sweetest 



