Course Content
Introduction to plant breeding
0/5
Introduction
Scope of plant breeding (Future Prospects)
Undesirable effects
History of plant breeding
Scientific contributions of eminent scientists
Domestication, plant introduction, and acclimatization
0/6
Acclimatization
Plant Introduction
Procedure of Plant Introduction
Purpose of plant introduction
Merits of Plant Introduction
Germplasm Collection
Modes of reproduction and pollination control
0/6
Mode of reproduction
Categories of mode of reproduction
Pollination
Mechanisms promoting self-pollination
Genetic Consequences of Self-Pollination
Genetic Consequences of Cross-Pollination
Qualitative and quantitative characters (qualitative and quantitative characters in crops and their inheritance)
0/2
Introduction
Role of the environment in Quantitative Inheritance
Biometrical techniques in plant breeding (assessment of variability, aids to selection, choice of parents, crossing techniques, genotype-by- environment interactions)
0/3
Introduction
Components of Genetic variance
Things to remember
Selection in self-pollinated crops (progeny test, pureline theory, origin of variation, genetic advance, genetic gain)
0/5
Progeny test
Pureline selection
General procedure for evolving a variety by pureline selection
Advantage of pureline selection
Origin of variation in pure lines
Hybridization techniques and its consequences (objectives, types, program, procedures, consequences)
0/4
Introduction
Some terminologies
Types of hybridization
Pre-requisites for hybridization
Genetic composition of cross-pollinated populations (Hardy-Weinberg law, equilibrium, mating systems)
0/4
Hardy-Weinberg law
Proof of Hardy-Weinberg law
Example of Hardy-Weinberg law
Factors affecting equilibrium frequencies
Selection in cross-pollinated crops (response and gain from selection, variability)
0/5
Introduction
MASS SELECTION
Recurrent selection
Procedure for Reciprocal recurrent selection
Half-sib and full-sib selection with progeny testing
Heterosis and inbreeding depression
0/5
Heterosis
Manifestations of Heterosis
Inbreeding depression
Degrees of inbreeding depression
Use of heterosis
Mutation breeding (types, use of mutagens, application)
0/8
Introduction
Classification of mutations
Characteristic feature of mutations
Procedure for irradiation
Selection of the variety and dose of mutagen
Mutation breeding for polygenic traits
Applications of Mutation Breeding
Advantages of mutation breeding
Polyploidy in plant breeding (aneuploidy, euploidy, allo- and autoploidy, applications)
0/6
Introduction
Origin and production of doubled chromosome numbers
Morphological and cytological features of auto polyploids
Application of Autopolyploidy in Crop improvement
Allopolyploidy
Limitations of Allopolyploidy
Breeding methods in self-pollinated crops (Mass, Pure line, Pedigree, Bulk, Backcross, etc)
0/5
Mass Selection
Bulk Method
Pedigree Method
Single Seed Descent
Backcross
Clonal selection
0/5
Clonal Selection
Advantages and disadvantages of clonal selection
Problems in Breeding asexually propagated crops
Genetic variation within a clone
Clonal degeneration
Release of new varieties
0/5
Introduction to Variety
Norms for Release of New Variety
Development of New Variety
Institutions Related with Release of Variety
Variety Release Procedure
Quality seed
0/4
Introduction
Importance of quality seed
Major seed quality characters
Characteristics of good quality seed
Breeding for pest resistance
0/3
Pest includes
Defense mechanisms of host against pathogen/parasite
Breeding for resistance
Intellectual property right
0/4
Introduction
Objectives
Types of Intellectual Property
Policy objectives favoring IPRs in new plant varieties
Learn Introductory Plant Breeding with Rahul
About Lesson

Inbreeding depression

  • Inbreeding or consanguineous mating is mating between individuals related by descent or ancestry.
  • The degree of inbreeding of an individual is expressed as inbreeding coefficient (F).
  • When the individuals are closely related, e.g., in brother-sister mating or sib mating, the degree of inbreeding is high.
  • Inbreeding depression may be defined as the reduction or loss in vigour and fertility as a result of inbreeding.
  • Inbreeding depression = F1-F2 / F1 x 100

 

Effects of inbreeding

  1. Appearance of Lethal and Sublethal Alleles :
  • IB results in appearance of lethal; sublethal and sub vital characters.
  • Eg : Chlorophyll deficiencies, rootless seedlings, flower deformities – They do not survive, they lost in population.
  1. Reduction in vigor :
  • General reduction in vigor size of various plant parts.
  1. Reduction in Reproductive ability :
  • Reproductive ability of population decreases rapidly.
  • Many lines reproduce purely that they cannot be maintained.
  1. Separation of the population into distinct lines :
  • Population rapidly separates into distinct lines i.e. due to increase in homozygosity.
  • This leads to random fixation of alleles in different lines.
  • Therefore, lines differ in genotype and phenotype. It leads to increase in the variance of the population.
  1. Increase in homozygosity :
  • Each lines becomes homozygous.
  • Therefore, variation within a line decreases rapidly. After 7-8 generations of selfing the line becomes more than 99% homozygous. These are the inbreds. These have to be maintained by selfing.
  1. Reduction in yield :
  • IB leads to loss in yield.
  • The inbreds that survive and maintained have much less yield than the open pollinated variety from which they have been developed.
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