Plant Genetics - Livro de bolso

PLANT GENETICS BY JOHN M. COULTER Head of the Department of Botany in the Untvemty of Chuaga AND MERLE C. COULTER Instructor in Plant - Gtitetu in the University of Chicago THE UNIVERSITY OF CHICAGO PRESS CHICAGO, ILLINOIS PREFACE There is developing an increasing demand for courses in genetics adapted to the needs of botanical students, and teachers of botany have asked repeatedly for a suitable text. A number of texts on heredity and evo lution have appeared, but these have contained far too little genetics. On the other hand, there are several very thorough texts on certain phases of genetics, but these have been more in the nature of monographs than texts. They have focused on too limited a field to give the reader any general appreciation of genetics as a whole and frequently have been too difficult for the uninitiated to appreciate at all. WALTERS Genetics is an admirable elementary text, but is not exactly adapted to the needs of the young botanist. All texts, in fact, have emphasized animal genetics more strongly than the student of botany needs, except certain books on plant breeding, which, however, are general in nature and give little attention to theoretical genetics. In short, the subject has been changing so rapidly that no one has ventured to write a general authoritative text. 1 The group that the present book is intended to serve primarily comprises those who intend to make botany their profession and who, although not as yet specialists, 1 After the manuscript of this text had gone to the printer, there appeared a book by BABCOCK and CLAUSEN, entitled Genetics in relation to agriculture. This is a general authoritative text for it contains a treatment of both plantand animal genetics, well suited to a thorough years course in genetics. vi Preface have had general training in the fundamentals of botany. Such students, for example, are commonly found in the last undergraduate year or first graduate year of their work with no distinct purpose to become geneticists, but wishing to be able to appreciate the important current work in plant genetics. Such a group of young botanists became evident at the University of Chicago. In their attack upon current botanical literature they frequently encountered papers dealing with plant genetics, but through lack of prepa ration were unable to grasp their significance. This type of literature seemed too important to be relegated entirely to the specialist, and therefore the authors of the present text organized a course of lectures to meet the need. The purpose of the lectures was not to develop professional geneticists, but merely to initiate students of botany into the point of view of working geneticists, so that they could appreciate an important phase of botanical literature. With such a purpose there was no attempt to give a complete presentation of modern genetics, but rather to introduce the student to genetics in the simplest way. As a consequence, for pedagogical reasons, certain perplexing facts were omitted, while others were slightly adjusted so as to convey the funda mental ideas without confusion. The result of the course was so successful as to suggest the desirability of putting the lectures into text form for the benefit of teachers who wish to profit by this experience. As a reference book it is entirely inadequate, much represen tative material having been omitted and only enough bibliographygiven to put the student upon the trail. As a textbook also it has two disadvantages i it Preface vii is avowedly not exact in some of the details 2 it is adapted definitely to young botanists with fairly thor ough elementary training. The excuse for the inexact ness of certain details is the pedagogical necessity. The preparation of a text for the students referred to is explained by the fact that it represents a very important group which has not been provided for...