Lecture Topics for Plant Breeding 450/550 Spring Term 1999

Plant Breeding 450/550

Spring Term 1999

List of Lecture Topics

Section I. Building a Foundation of Concepts and Terminology

Introduction and definition of plant breeding

Reproductive systems in relation to breeding methods

Natural methods of pollination control (dioecy, monoecy, dichogamy, incompatibility, and male sterility)
Estimation of % outcrossing

Genetic principles

Phenotype, genotype, and environment
Qualitative and quantitative traits
Qualitative traits in populations
- Hardy-Weinberg equilibrium
- Effect of selection (before and after pollination) on gene and genotype frequency
Quantitative traits
- Heritability & combining ability
Transgressive Segregation
Chimeras

Germplasm

Evolution of crop plants, including changes under domestication
Vavilov's centers of diversity
CGIAR international centers
Germplasm collection, preservation, evaluation, and distribution
The U.S. national plant germplasm system

Section II. Steps in Plant Breeding Programs

General outline of a plant breeding program

Objectives of plant breeding programs

Making controlled pollinations

Choosing parents
General guidelines and a few tricks for various crops
Interspecific hybridization

Consequences of self-pollination and the pure line concept

Selection in a naturally variable population

** Exam 1 **

Breeding methods: the four basic schemes (IBL, OPP, CLO, HYB)

1. IBL: Breeding methods for self-pollinated crops following a controlled cross

Pedigree method, need for ruthless selection

Bulk method, effect of natural selection

Single-seed descent method

Doubled haploids

Backcross method & minimum number of plants required

2. OPP: Breeding methods for cross-pollinated crops

History of hybrid maize

Inbreeding depression and heterosis

Dominance and overdominance hypotheses

Mass Selection

Ear-to-row method

Phenotypic recurrent selection

Recurrent selection based on progeny tests

Polycross progeny tests and synthetic varieties

Genetic shift

3. CLO: Breeding methods for vegetatively propagated crops

A single controlled cross

Modified backcross method

Spontaneous mutations

Special problems - virus diseases and fertility reduction

Apomictic grasses

** Exam 2 **

4. HYB: F₁ hybrid cultivars

Increased value of hybrid cultivars

Reducing the cost of hybrid seed production

Current procedures in maize

Current status in various other crops

Cultivar naming, release, distribution, maintenance, and protection

Release procedures at agricultural experiment stations
Release procedures in private companies
Seed certification programs
Legal protection of new cultivars
- Plant patents, utility patents, plant variety protection
Trademarks
Release notices - examples from HortScience and Crop Science

Breeding for disease resistance

Categories of causal organisms from a plant breeding perspective
Disease epiphytotics
Vertical and horizontal resistance
- Races and the gene-for-gene concept
Methods of identifying resistant genotypes
Using resistant genotypes to control disease
Genetic vulnerability of major crop plants

Heterozygosity, heterogeneity, and yield stability

Applications of biotechnology in plant breeding programs

Tissue culture
- Micropropagation
- Doubled haploids from anther and ovule culture
- Embryo rescue in interspecific crosses
- Somaclonal variation
- In vitro selection
- Protoplast fusion
Molecular genetics
- Central dogma of genetics
- Types of molecular markers and applications
- Agrobacterium-mediated transformation
- Other methods of transformation
- Challenges and examples of successes

** Final Exam (comprehensive) **

CSS 450/550 & HORT 450/550
Plant Breeding
Instructor: Shawn A. Mehlenbacher
Webmaster: Sara Griffith
Last Updated: April 22, 1999