Contents -- Figures and Tables -- Preface -- Acknowledgments -- Introduction -- 1 Concepts of Plant Reproduction, Variation, Heredity, and Breeding: A Brief History -- Genetics and Plant Breeding in Europe, 1700-1900 -- Quantitative Methods -- Development of Methods and Programs -- 2 Population Genetics -- Genetic Processes -- Genetic Systems -- 3 Environmental Influences and Geographic Variation -- Physical Factors Influencing Natural Selection -- Geological History -- Seasons, Climate, and Phenology -- Regional Differences in Ecology and Genetic Systems -- Experiments: The Theory -- Variation Patterns -- Variation Patterns: General Conclusions -- 4 Genetic Variation in Some Major Species -- Angiosperms -- Gymnosperms -- 5 Geographic Variation and Silviculture -- Control of Seed Origin -- Seed Zones and Seed Transfer -- Seed Transfer: Methods and Examples -- Species Introduction -- 6 Conservation of Genetic Resources -- The Need for Gene Conservation -- Objectives of Gene Conservation Programs -- Measures of Genetic Diversity -- Methods -- Gene Conservation Programs -- Literature Cited -- Species Index -- A -- B -- C -- D -- E -- F -- G -- H -- J -- L -- M -- N -- O -- P -- Q -- R -- S -- T -- U -- Subject Index -- A -- B -- C -- D -- E -- F -- G -- H -- I -- J -- K -- L -- M -- N -- O -- P -- R -- S -- T -- U -- V -- W -- Y -- Z.