Quantitative Genetics And its Applications.pptx

1. QUANTITATIVE
GENETICS AND ITS
APPLICATIONS

2. Contents
◦ Types of Traits.
◦ Quantitative Genetics.
◦ Assumption for effective observation of phenotype in quantitative
genetics.
◦ Application of Quantitative Genetics in Plant Breeding.

3. Types of Traits
Qualitative Traits
Quantitative Traits

4. Types of Traits
Qualitative Traits
Described according to kind.
Discontinuous Variation.
Monogenic/Oligogenic.
Related with Individual Mating and their progenies.
Estimation based on counts and ratios.
Form (Round/Wrinkled),
Coat color of Guinea pig(Black/White) etc.

5. Types of Traits
Quantitative Traits
Described in term of degree of expression.
Continuous Variation
Polygenic
Population of individuals comprises diversity of
mating kind.
Estimates of population parameters using statistical
tools.
Skin Color, Seed color of wheat, Ear size of maize,
etc.

6. Types of Traits
Difference On Qualitative Traits Quantitative Traits
Nature of Traits Described according to kind. Described in term of degree of
expression.
Scale of Variability Discontinuous Variation. Continuous Variation.
Number of Genes Monogenic/Oligogenic. Polygenic.
Mating Pattern Related with Individual Mating and their
progenies.
Population of individuals
comprises diversity of mating kind.
Statistical Analysis Based on counts and ratios. Estimates of population
parameters using statistical tools.
Examples: Form (Round/Wrinkled),
Coat color of Guinea pig(Black/White)
etc.
Skin Color, Seed color of wheat,
Ear size of maize, etc.

7. Quantitative Genetics
◦ Branch of genetics dealing with the quantitative traits.
◦ Influenced by multiple genes as well as environment that plays a
significant role in the expression of traits.
◦ Aims to understand and predict the inheritance pattern of quantitative
traits.
◦ Estimating the relative contribution of genetics and environment
factors to the phenotypic expression.

8. Assumption for effective observation of
phenotype in quantitative genetics.
◦Reference population defined.
◦Absence of linkage.
◦Presence of diploid Mendelian inheritance.
◦Absence of selection during the formation of inbred lines.
◦No breeding of the reference population.

9. Application of Quantitative Genetics in Plant
Breeding.
◦Selection of Quantitative Traits
◦Trait Evaluation and its variation
◦Trait Improvement through Genomic Selection
◦Germplasm Evaluation and Utilization
◦Hybridization and Hybrid Vigor
◦Breeding Value Estimation

10. Application of Quantitative Genetics in Plant
Breeding.
Selection of Quantitative Traits
◦ Used to select for quantitative traits that are
difficult to measure directly, such as disease
resistance or drought tolerance.
◦ Uses indirect selection, which involves selecting
for correlated traits that are easier to measure, but
which are genetically linked to the desired trait.

11. Application of Quantitative Genetics in Plant
Breeding.
Evaluation of Traits and its Variability
◦ Allows breeders to estimate the heritability of
quantitative traits.
◦ Helps to estimate the proportion of the
phenotypic variation that is due to the genetic
factors.
◦ Know the contribution of genetic and environmental
factors to the phenotypic variation observed in
these traits.
◦ Traits with high heritability are more likely to
respond to selection, allows to focus on those traits.

12. Application of Quantitative Genetics in Plant
Breeding.
Trait Improvement through Genomic Selection
◦ Done through marker-assisted selection, where
molecular markers linked to desired traits are
used to screen large populations and select plants
with the desired genetic makeup.
◦ Accelerates the breeding process by allowing early
selection based on genetic potential.

13. Application of Quantitative Genetics in Plant
Breeding.
Hybridization and Hybrid Vigor
◦ Plays a role in understanding and harnessing
hybrid vigor.
◦ Can develop hybrid combinations that exploit
heterosis (hybrid vigor) for improved yield, disease
resistance, or other desirable traits by
understanding the genetic basis of complex
traits.
◦ Used to predict the performance of hybrid
combinations based on the combining ability of
parental lines.

14. Application of Quantitative Genetics in Plant
Breeding.
Germplasm Evaluation and Utilization
◦ Enables the assessment of genetic diversity within
germplasm collections.
◦ Studies the genetic variation and trait performance
of different crops,
◦ Allows to identify valuable genetic resources and
incorporate them into breeding programs
◦ Creates novel traits or enhance genetic diversity.

15. Application of Quantitative Genetics in Plant
Breeding.
Breeding Value Estimation
◦ Allows breeders to estimate the breeding value of
plants, which represents their genetic merit for a
specific trait.
◦ Estimation considers both the individual's own
phenotype and the genetic information of its
relatives.
◦ Helps breeders make informed decisions about
which plants to use as parents in breeding
programs.

16. Application of Quantitative Genetics in Plant
Breeding.
In short,
Scientific framework, to understand
1. Genetic architecture of complex traits.
2. Select superior plants,
3. And accelerate the development of improved cultivars
with enhanced agronomic traits, productivity, and adaptability.

17. Thank You!