1921-22.] BOTANICAL SOCIETY OF EDINBURGH 81 



records and opened the wa}- for an important development. 

 Plant breeding of crop-plants was carried on by Vilmorin 

 about 1850, and later by others like Garton, but in these 

 commercial enterprises it was not to be expected that the 

 actual methods would be adequately disclosed. About 

 1870 Denmark became the leader in State organisation of 

 agricultural research, and the example has been followed 

 by other countries. Sweden in 1886 established a seed 

 association in connection wuth the plant-breeding work at 

 the experimental farm at Svalof, and at the present time 

 two of the more productive oats in Scotland — Victory 

 and Crown — are varieties obtained at Svalof within the 

 present century. Plant breeding in Ireland during the 

 same twenty years has entirely changed the varieties of 

 barley grown there. Similar w^ork by State departments 

 in Canada and the United States has greatly increased the 

 yield and value of wheat and oats in North America. 



Two chief methods are used in plant breeding : selec- 

 tion or the search for new varieties as variations or 

 mutations from existing races ; hybridisation to combine 

 the characters of parents, followed by selection of the more 

 useful progeny. Neither of the methods is new. Pliny 

 (23-79 A.D.) describes cabbage, tall and dwarf kale, kale- 

 sprouts, and kohl-rabi, all varieties obtained by con- 

 tinuous selection from the wald cabbage. In 1597 Gerard 

 illustrated red and white cabbages, brussels sprouts, and 

 cauliflower, in all fifteen varieties. Numerous varieties of 

 farm and garden crops were described by Lawson of Edin- 

 burgh in 1850, mostly the produce of selection. Now 

 plant improvement by selection can be carried out more 

 rapidly and with fewer mistakes. Hybridisation has, 

 however, made very distinct progress in the last twenty 

 years. Kohlreuter (1760-1766) established the import- 

 ance of insects and wnnd as agents in cross-pollination. 

 Thomas Andrew Knight in 1779 published his results in 

 crossing peas and various fruit trees. Other landmarks 

 are Gaertner's book in 1849 and Naudin's Essays in 1862. 

 Charles Darwin, in gathering material for his " Origin of 

 Species" (1858) brought together much information on 

 plant breeding by hybridisation and by selection. About 

 1860 it is evident that much was known, but the knowledge 



