128 



The Journal of Heredity 



attempted to evolve these specific 

 forms. 



On the other hand, many instances 

 might be quoted in which imj^rovement 

 has been effected by systematic breed- 

 ing. 



Perhaps the most striking case is that 

 illustrated by the development of the 

 sugar content in beets. By a process 

 of careful, repreated, and systematic 

 selection of individual plants of high 

 sugar content, combined with the re- 

 peated testing of the hereditary powers 

 of each individual jjlant, the common 

 beet, containing from 6 to 7% of sugar, 

 has been developed into the sugar beet, 

 containing from 20 to 25% of sugar. 



The value of this improvement must 

 be obvious. It has enabled the beet- 

 sugar industry in Euroi)e and America 

 to more than hold its own against the 

 cane sugar produced by black labor 

 in the Tropics. 



A remarkable case of selection is 

 referred to in De Vries'^ work. In 1886. 

 De Vries found at Loosdrecht a ])lant of 

 clover bearing a few leaves with four 

 and five leaflets. He commenced some 

 jxi:)eriments to fix this type of clover. 

 By continuous cultivation and selection, 

 he ultimately (1892) secured plants in 

 which four and fi\'c leaflets on each 

 leaf were common, and, strangely 

 enough, for the first time several leaves 

 appeared with six and seven leaflets. 



It is very probable that no clo\-er 

 I)lant in the world ever possessed six or 

 seven leaflets until De Vries commenced 

 these exjjeriments. 



HISTORY OF WHEAT SKLIiCTION. 



The idea of improving cereals by 

 selection is of comparatively recent 

 origin. The most notable of the early 

 wheat-V)reeders were Le Couteur, of 

 Jersey; Shireff, of Haddington; and 

 Hallet, (jf Brighton. 



Le Couteur, nearly a century ago, 

 observed that an ordinary field of wheat 

 appeared to be extremely variable, and 

 concluded that some of the various 

 types found in the growing crop would 

 yield better than others. He isolated 

 23 distinct tyjjcs, and grew them se])a- 

 rately, and was successful in introducing 



se\'eral new \-arieties into general culti 

 vation. One of these is still grown 

 under the name of Talavera. 



A Scottish agriculturist — Patrick 

 Shireff — developed the celebrated Hope- 

 town oats in 1832, and placed on the 

 market four distinct varieties of wheat, 

 all of which were extensively grown in 

 his time. His method of procedure 

 was to walk through his wheat fields at 

 harvest-time, and mark any plants 

 which stood out ]:)romincntly from the 

 surrounding jjlants. He isolated these 

 plants, sowed them separately, sub- 

 jected them to severe tests, and sold 

 the seed of the most promising types. 



It is very interesting to note that 

 neither of these breeders adopted the 

 princi]jle of repeated selection. They 

 simply isolated individual plants of 

 ]:)romising a])pearance, and multiplied 

 the seed of these types as rapidly as 

 possible. There was but one initial 

 selection, followed by rapid multiplica- 

 tion of the progeny. On this funda- 

 mental ]3oint they differed widely from 

 Major Hallet, who began his work of 

 selection in 1857. His method of selec- 

 tion was derived from his j^revious 

 experience of breeding Shorthorn cattle. 



He first introduced the princii^le of 

 repeated selection. His method was to 

 select each year the best grain from the 

 best ear of the best plant he could find 

 in his wheat-field, and to repeat this 

 process for a number of generations 

 On 18th June, 1862, he inserted a full- 

 ]jage advertisement in the Times, de- 

 scribing his methods of breeding wheats. 

 In this advertisement he states that his 

 "pedigree wheat was bred upon the 

 same principle of repeated selection 

 which has jjroduced our ]mre races of 

 animals." 



During his first five years' work, the 

 length of the head was doubled, the 

 number of grains in the head trebled, 

 and the tillering capacitv was increased 

 fivefold. 



The imjjrovements effected were, in a 

 measure, artificial, inasmuch as he grew 

 his selected ]jlants on the very best and 

 richest garden soil. Nevertheless, his 

 strains were a success, and greatly 

 imjjroved the harvests of his generation. 



•De Vries: "The Mutation Th.'ory," Vol. II., p. 36 (1010). 



