PLANT-BREEDING 



COMMENTS ON THE EXPERIMENTS OF NILSSON AND BURBANK 



CONTENTS 

 I. EVOLUTION AND MUTATION ..... i 



II. THE DISCOVERY OF THE ELEMENTARY SPECIES OF AGRI- 

 CULTURAL PLANTS BY HJALMAR NILSSON. 



A. Different Principles in the Breeding of Cereals . . 29 



B. The Swedish Agricultural Experiment Station at Svalof 48 

 C..The Svalof Method of Producing Improved Races . 67 

 D. A Criticism of the Method of Continuous Selection . 90 



III. ON CORN-BREEDING . . . . . . .107 



IV. THE PRODUCTION OF HORTICULTURAL NOVELTIES BY 



LUTHER BURBANK. 



A. Methods and Material . . . . . . 159 



B. New Varieties in Fruits and Flowers . . .178 



C. Hybridization and Selection ..... 202 



D. Mutations in Horticulture . . . . .221 



V. THE ASSOCIATION OF CHARACTERS IN PLANT-BREEDING. 



A. Association of Characters in Nature . . -237 



B. Correlations in Agricultural Breeding . . -255 



C. A Methodical Study of Correlations . . .271 



D. Correlations in Fluctuating Variability . . . 289 



E. Unit-Characters ....... 309 



VI. THE GEOGRAPHICAL DISTRIBUTION OF PLANTS . . 333 







INDEX 353 



