Plant-breeding; being five lectures upon the amelioration of domestic plants

Preface

There is no subject associated with the care of plants respecting wliich there is so much misapprehension and imperfect knowledge, as that of the origination of ncAV forms. Most of the scattered writing touching it treats the subject as if all our knowledge of the matter were and must be derived wholly from experiment. It therefore recites examples of how this and that new form has come to be, and has made little attempt to discover the fundamental causes of the genesis of the novelties. Horticulturists commonly look upon each novelty as an isolated fact, whilst we ought to regard each one as but an expression of some law of the variation of plants. It is the common notion, too, to consider any type of plant to be essentially a fixed entity, and to regard any marked departure from the type as a phenomenon rather more to be

Vi PREFACE.

wondered at tlian to be explained. It is evident, however, that one cannot understand the production of new varieties until he has grasped some of the fundamental principles of the onward progression of the vegetable kingdom. Any attempt, therefore, to explain the origin of garden varieties, and the methods of producing them, must be at the same time a contribution to the literature of the philosophy of organic evolution.

I do not know of any explicit and sustained attempt to account for the evolution of all garden forms, and I have therefore brought together in this volume the subject-matter of various lectures which I have been in the habit of giving before my students. The first and third lectures Avere newly elaborated the present summer for two addresses before the class in biology Avhich came together at the University of Pennsylvania, under the auspices of the American Society for the Extension of University Teaching. The second lecture was first presented before the Massachusetts State Board of Agriculture, in Boston, December 1, 1891. In April, 1892, it Avas republished, with a bibli-

PEEFACE. Vll

ography of the subject, by the Rural Publishing Co., under the title, '' Cross-Breeding and Hybridizing." This publication is now out of print. I have made no attempt to collect lists or catalogues of varieties, but have endeavored to make very brief statements of some of the underlying principles of the amelioration of plants, with only sufficient examples to fix them in the mind.

I hope that teachers of horticulture and botany may find the book useful in their classes. When it is necessary to abridge the instruction or to present it to untrained students, only Lectures III. and V. may be used, for these contain the matters of greatest demonstrative importance.

L. H. Bailey.

Cornell University, Ithaca, N.Y., September 1, 1895.

Contents

LECTURE I.

PAGE

The Fact and Philosophy of Variation ... 1