PREFACE 



Since the early development of agriculture by primitive 

 peoples, selection of seed for planting has been an important 

 feature of agricultural practice. While many of our better 

 varieties or strains of crop plants have originated as chance 

 seedlings or from selections made by men who lacked a knowledge 

 of the laws of heredity, there has been a growing appreciation 

 in recent years of the value of training students for the occupa- 

 tion of plant breeding. 



Studies in crop genetics carried on since 1900, as well as 

 studies in field plot technic, have helped in a large measure 

 to standardize methods of breeding. Information regarding 

 the mode of inheritance of particular characters as well as a 

 better knowledge of the wild relatives of our crop plants is con- 

 stantly being obtained. The purpose of this book is to present 

 fundamental principles of crop breeding and to summarize 

 known facts regarding the mode of inheritance of many of the 

 important characters of crop plants. Much of the material 

 here presented has been used in courses in crop breeding which 

 have been given in recent years at the College of Agriculture, 

 University of Minnesota. 



Suggestions from others in relation to methods of treatment 

 of various subjects have been of material value. Particular 

 mention should be made of the helpful advice of Dr. M. J. 

 Dorsey regarding the chapters on " Plant Genetics" and " Fruit 

 Breeding;" of F. A. Krantz regarding the chapter on "Potato 

 Breeding," and of John Bushnell and W. T. Tapley regarding 

 the chapter on "Vegetable Breeding." 



We are also indebted to Miss Alice McFeely, Bulletin Editor, 

 for many suggestions regarding presentation and for assistance 

 in proofreading; to Mr. A. N. Wilcox for assistance in proof- 

 reading; to Miss L. Mae Centerwall for help in obtaining a con- 

 siderable number of publications from other libraries; and to 

 Miss Alma Schweppe for checking the literature citations. Pre- 

 vious summaries of certain phases of plant breeding methods were 



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