Skip to main content
Biology LibreTexts

1: Chapters

  • Page ID
    121778
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \( \newcommand{\dsum}{\displaystyle\sum\limits} \)

    \( \newcommand{\dint}{\displaystyle\int\limits} \)

    \( \newcommand{\dlim}{\displaystyle\lim\limits} \)

    \( \newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\)

    ( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\id}{\mathrm{id}}\)

    \( \newcommand{\Span}{\mathrm{span}}\)

    \( \newcommand{\kernel}{\mathrm{null}\,}\)

    \( \newcommand{\range}{\mathrm{range}\,}\)

    \( \newcommand{\RealPart}{\mathrm{Re}}\)

    \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\)

    \( \newcommand{\Argument}{\mathrm{Arg}}\)

    \( \newcommand{\norm}[1]{\| #1 \|}\)

    \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\)

    \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    \( \newcommand{\vectorA}[1]{\vec{#1}}      % arrow\)

    \( \newcommand{\vectorAt}[1]{\vec{\text{#1}}}      % arrow\)

    \( \newcommand{\vectorB}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \( \newcommand{\vectorC}[1]{\textbf{#1}} \)

    \( \newcommand{\vectorD}[1]{\overrightarrow{#1}} \)

    \( \newcommand{\vectorDt}[1]{\overrightarrow{\text{#1}}} \)

    \( \newcommand{\vectE}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{\mathbf {#1}}}} \)

    \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \)

    \(\newcommand{\longvect}{\overrightarrow}\)

    \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)

    \(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)

    • 1: Gene Frequencies
      This page explores the complexities of linking quantitative traits to genetic units, rooted in Modern Synthesis theory. It emphasizes mutation, selection, and drift's roles in allele frequency dynamics, particularly in relation to natural selection, population size, and inbreeding. Non-random mating affects genotype frequencies, while theoretical predictions of genetic variation may differ in practice.
    • 2: Linkage
      This page explores plant breeding population dynamics influenced by selection, drift, and migration, focusing on gametic and linkage disequilibrium as deviations from Hardy-Weinberg Equilibrium. It emphasizes the significance of understanding these concepts in genetics, outlines learning objectives on linkage and recombination, and discusses methods for analyzing genetic loci disequilibrium, including Z and chi-square statistics.
    • 3: Resemblance Between Relatives
      This page discusses the influence of population genetics on plant breeding, focusing on factors like selection and migration that lead to population disequilibrium. It examines inbreeding coefficients and genetic relationships, tracing their development and application in breeding. The text explains mating scenarios using equations to connect various indices and probabilities of allele identity, with implications for genetic diversity and breeding strategies.
    • 4: Measures of Similarity
      This page discusses the organization of breeding populations, focusing on the contrast between ideal reference populations and sub-populations using examples from maize, sorghum, and barley. It emphasizes the application of pedigree and molecular marker data to understand genetic relationships through matrices and multivariate methods like Principal Component Analysis (PCA).
    • 5: Gene Effects
      This page explores the contributions of R.A. Fisher's model to genetics, focusing on the interpretation of data and predictions in plant breeding. It covers key concepts such as genotypic and phenotypic values, dominance, and allele interactions, including epistasis. The text emphasizes calculating population means, breeding values, and genetic effects, highlighting how additive genes and genotype interactions affect phenotypes.
    • 6: Components of Variance
      This page explores phenotypic variation sources, focusing on genetic and environmental influences on trait heritability. It details variance components such as additive, dominance, and epistatic variances, defining broad and narrow-sense heritability for practical applications in breeding.
    • 7: Estimates of Variance
      This page explores heritability estimation in quantitative genetics, focusing on genetic variance and covariance among relatives, particularly in plant breeding. It covers modeling genetic variance, deriving variance components through ANOVA, and estimating variances in F2 and F3 progenies.
    • 8: Mating Designs
      This page covers various mating designs and statistical methods in plant breeding for estimating genetic variability, focusing on diallel crosses and the Gardner and Eberhart Diallel Analysis for evaluating gene effects like general and specific combining abilities.
    • 9: Selection Response
      This page covers principles and practices of selection in crop improvement, focusing on genetic gain and the importance of estimating heritability. It details concepts such as selection differential, the relationship between responses to selection and progeny phenotypes, and the use of equations for genetic gain and heritability estimation. Methods for estimating narrow-sense heritability using ANOVA and REML are discussed, along with the significance of family variance.
    • 10: G x E
      This page explores the complexities of genotype-by-environment (GxE) interactions in plant breeding, highlighting various types of GxE responses and the importance of understanding them for cultivar development. It emphasizes the need for effective sampling of environments, detailed statistical methods for quantifying variances, and strategies for improving decision-making.
    • 11: Multiple Trait Selection
      This page explores methods for improving plant cultivars through various selection techniques, including multistage and index selection. It emphasizes maximizing genetic gain and the application of selection indices like the Smith-Hazel index to predict breeding values. It details the theory behind indexing, including phenotype relationships and genetic optimization, while introducing different selection indices, such as the multiplicative and desired gain indices.
    • 12: Multi Environment Trials- Linear Mixed Models
      This page explores the limitations of general linear models in predicting outcomes from replicated trials in multi-environment contexts. It introduces mixed linear models (LMM) and discusses BLUEs and BLUPs for enhancing prediction accuracy, particularly in plant breeding. C.R. Henderson's shrinkage estimators are featured for improving genotypic predictions, along with a distinction between fixed and random effects.
    • 13: Simulation Modeling
      This page discusses quantitative genetic models and their relevance in plant breeding, highlighting the historical debate between Fisher and Wright on model complexity. It addresses the practical application of simulation modeling using Excel to analyze genetic contributions, including SNP genotypes and phenotypic traits.
    • 14: Plant Breeding Basics
      This page explores plant breeding fundamentals, data management, and statistical modeling techniques. Key topics include genetic improvement goals, mixed linear models, data types, and the significance of exploratory data analysis (EDA). It discusses fixed vs. random effects, hypothesis testing, power of tests, and methods like ANOVA and AOC for data analysis. The use of R and RStudio for data manipulation is emphasized, alongside error types in statistical inference.
    • 15: Applied Learning Activities
      This page provides downloadable Applied Learning Activities (ALAs) and related files for chapters on plant breeding and genetics. Resources include PDFs, CSVs, and Excel files covering topics such as genetic variance, heritability, and simulation modeling. The chapters span foundational to advanced concepts, equipping users for practical applications in genetic analysis and plant breeding.


    This page titled 1: Chapters is shared under a not declared license and was authored, remixed, and/or curated by Walter Suza and Kendall Lamkey (Iowa State University Digital Press) via source content that was edited to the style and standards of the LibreTexts platform.