Introduction to Forest Genetics

Introduction to Forest Genetics examines some of the basic genetic concepts typically used in forestry and tree improvement studies, including Mendelian and population genetics. It also describes techniques that are generally useful in tree improvement work, including individual tree selection and breeding, provenance testing, species and racial hybridization, and introduction of exotics. Organized into 19 chapters, this volume begins with an overview of forest genetics and problems associated with forest genetics. It then discusses concepts from basic genetics, including chromosome structure and function; DNA and RNA; nongenetic inheritance; and genotype versus phenotype. Other chapters focus on inbreeding: complete elimination of homozygous recessive trees; mutation and migration; and controlled pollination and vegetative propagation. The book also covers the establishment and measurement of test plantations; general principles and methods of selective breeding; choice of breeding method and type of seed orchard; heritability and genetic gain; geographic variation in Scotch pine and American trees; species and racial hybridization; chromosome studies; and polyploidy and haploidy breeding. This book is a valuable resource for foresters, professional tree breeders, and those with or without previous training in genetics or forestry.

Preface

Acknowledgments

1 Introduction

Problems Peculiar to Forest Genetics

The Possibilities of Tree Improvement

General Sources of Information

2 Concepts from Basic Genetics

Chromosome Structure and Function

DNA and RNA

Genes

Nongenic Inheritance

Genotype versus Phenotype

Cell Division and the Opportunity for New Gene Combinations

Study Questions

Suggested Reading

3 Additional Basic Genetic Concepts

Inbreeding

Hybrid Vigor

Recovery Ratios in the F2 Generation

Study Questions

4 Population Genetics—Selection

Definitions

Hardy-Weinberg Equilibrium

Complete Elimination of Homozygous Recessive Trees

Partial Selection against Récessives

Selection Favoring Récessives (against Dominants)

Selection for Genes with Additive Effects

"Fitness" and Fisher's "Fundamental Theorem"

Selection for and against Hétérozygotes

Selection in Small Populations

How to Increase Selection Pressure

A Word Picture of Selection

Recapitulation

Study Questions

5 Population Genetics—Mutation, Migration, Isolation

Mutation

Migration

Isolation

Study Questions

6 Useful Techniques—Controlled Pollination

Selection of Parent Trees

Climbing

Bagging to Prevent Outside Pollination

Pollen Handling

Pollination Procedures

Indoor Controlled Pollination

Fruit Collection and Seed Handling

Success Expected from Controlled Pollination

Study Questions

7 Useful Techniques—Vegetative Propagation

Introduction

Grafting and Budding

Propagation by Stem Cuttings

Propagation by Root and Root-Stem Cuttings

Propagation by Leaf Cuttings

Root Suckers

Other Methods of Occasional Interest

Apomixis

Topophysis or Persistent Nongenetic Effects

Study Questions

8 Useful Techniques—Establishment and Measurement of Test Plantations

Introduction

Definitions

Commonly Used Experimental Designs

Nonstatistical Considerations

Statistical Considerations

Sample Schedules for Experiment Establishment

Hints on Measurement and Data Recording

Study Questions

9 Selective Breeding—General Principles and Methods

Role of Selective Breeding in Tree Improvement

General Principles

Breeding Methods Described

Study Questions

10 Choice of Breeding Method and Type of Seed Orchard

Factors Affecting Choice

Thinned Natural Stands versus Planted Seed Orchards

Mass versus Family Selection

Half-Sib versus Full-Sib Progeny Testing

Half-Sib versus Full-Sib Family Selection

Progeny Test Seed Orchards versus Clonal Seed Orchards

Earliness of Flowering on Grafts and Seedlings

Study Questions

11 Examples of Progress through Selective Breeding and Seed Orchard Management

Introduction

Examples of Simple Inheritance

Variation and Improvement in Quantitative Traits

Seed Orchard Management in Loblolly and Slash Pines

Management of Seedling Seed Orchards of Red Pine

Special Cases

Study Questions

12 Estimation of Heritability and Genetic Gain

Experimental Procedures and Applicability of Estimates

Parent-Progeny Regression

Variance Analysis—Half-Sib Progeny Test

Variance Analysis—Full-Sib Progeny Test

Conversion of Family to Single Tree Heritabilities

Variance Analysis—Clonal Test

Genotype-Environment Interaction—Effect on Breeding Plans

Study Questions

13 Provenance Testing

Role of Provenance Tests in Tree Improvement

Factors Influencing Amount of Geographic Variability

General Geographic Trends

Knowns and Unknowns about Natural Selection

Design of Provenance Tests

Practical Use of Provenance Data

Study Questions

14 Geographic Variation in Scotch Pine

Introduction

Phenotypic versus Genetic Variation Patterns

Amount and Pattern of Genetic Diversity

Description of Varieties

Practical Use of Scotch Pine Provenance Data

Typical and Atypical Aspects of Scotch Pine

Study Questions

15 Geographic Variation in American Trees

The Pacific Coast, California to Alaska

Western United States—A Region of Great Diversity

Boreal America—A Region of Clines and Great Genetic Diversity

Slight to Moderate Variation in Northeastern Species

Geographic Variation in the Central Hardwoods

Southeastern United States—A Region of Moderate Genetic Diversity

Study Questions

16 Species and Racial Hybridization

Use of Hybridization in Agriculture

Goals of Hybridization in Trees

Crossability Patterns

Hybridization and Evolution

Crossability Patterns by Genus

Study Questions

17 Species and Racial Hybridization—Practical Application

Historical Background

Mass Produced F 1 Hybrids

Utilization of F 2 Generation Hybrids

Hybridization and Subsequent Selection in Later Generations

Study Questions

18 Introduction of Exotic Species

Introduction

Reasons for Expecting Success from Exotics

Factors Governing Successful Introduction

Exchange Relationships among Regions

Methods of Introducing and Testing New Species

Examples of Successful and Unsuccessful Exotics

Regional Summaries of the Use of Exotics

Study Questions

19 Polyploidy, Aneuploidy, and Haploidy

Definitions

Techniques of Chromosome Study

Karyotypes of Pines

Rareness of Polyploidy in Gymnosperms

Importance of Polyploidy in Angiosperms

Breeding Behavior of Polyploids and Aneuploids

Induction and Recognition of Polyploidy

Haploid Breeding

Study Questions

Appendix: Common and Scientific Names of Trees

Bibliography

Glossary

Index