SELECTION 



WITHOUT 



ARTIFICIAL CKOSSIXG. 



31 



In nearly all cases these sports dili'er from the plant on which they 

 originated by lack of characters that are visible in the mother plant. 

 Occasionally, however, the reverse is true. But when a new charac- 

 ter appears in a bud sport it is in nearly all cases a character common 

 to the species, which was presumably latent in the mother plant. 



The Ethel ^laule dahlia furnishes what appears to be an example. 

 This is sold as pure white. Mr. TT. A. Andrews, of Washington, 

 D. C, has grown this dahlia for four years. Last year (190S) one of 

 the plants produced flowers having a decided pink tinge, especially 

 in the center of the flowers. This year he has several of the plants 

 produced (by division) from the pink-flowered one of last year, and 

 all of them show the pink color. All the plants of this variety in 

 Mr. Andrews's garden have been propagated by division from a single 

 plant obtained four years ago. Presumably the pink color is latent 

 in the original stock and has been partially revived in these pink- 

 flowered individuals. 



In those vegetativeh" propagated plants where variation occurs by 

 hereditary characters becoming latent — and this type of variation 

 seems to be quite common, especially in potatoes — selection of seed is 

 of great importance. In this case selection enables the breeder to 

 keep his stock up to standard, at least much longer than woidd be the 

 case without selection, and where variation occurs by the develop- 

 ment of characters which were previously latent it enables him to 

 preserve such variations when they are of value. 



The residts of the application of the principles here stated to the 

 selection of seed potatoes have been in some cases quite marked. 

 For instance, a potato grower in Michigan some years ago began the 

 practice of digging by hand enough potatoes for seed and saving only 

 those hills that had six or more merchantable tubers and no small 

 tubers. TTlien he first began this practice he found only sixteen 

 hills out of each hundred dug that came up to his standard; but after 

 he had continued the practice for five years the number of such hills 

 had risen to seventy in a himdred. Under the direction of Mr. L. G. 

 Dodge, of the Office of Farm Management, several Xew England 

 potato growers have been applying these principles for two years 

 past. The first year there was an average of about eight hills per 

 hundred that came up to standard. The second year from seventeen 

 to twenty hills met tlie conditions. This is as far as the experiment 

 has proceeded at the present time. Some work done on potatoes by 

 Mr. C. W. Waid. of the Ohio Agricultural Experiment Station, has 

 given similar results. In this work, starting with the same original 

 lot of tubers, three strains were grown, as follows: (1) Seed from 

 high-yieldiiig hills, (2) seed from low-jdelding hills, and (3) imselected 



81599°— BiiL 165—11 3 



