Inbreeding is the production of offspring from the mating or breeding of individuals or
organisms that are closely related genetically.By analogy, the term is used in human
reproduction, but more commonly refers to the genetic disorders and other consequences that
may arise from expression of deleterious or recessive traits resulting from incestuous sexual
relationships and consanguinity. Inbreeding results in homozygosity, which can increase the
chances of offspring being affected by deleterious or recessive traits.This usually leads to at least
temporarily decreased biological fitness of a population(called inbreeding Common fruit fly
females prefer to mate with their own brothers over unrelated males. depression), which is its
ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially
referred to as inbred. The avoidance of expression of such deleterious recessive alleles caused by
inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossing.
Crossbreeding between populations also often has positive effects on fitnessrelated traits, but
also sometimes leads to negative effects known as outbreeding depression. However increased
homozygosity increases probability of fixing beneficial alleles and also slightly decreases
probability of fixing deleterious alleles in population. Inbreeding can result in purging of
deleterious alleles from a population through purifying selection.
Centres of diversity – types of biodiversity – Centres of origin – Law of homologous series – centers of origin – types of centres of diversity – gene sanctuaries – genetic erosion – main reasons of genetic erosion – extinction – introgression – gene banks – types of gene banks
This P.P.T is about a chapter reproduction in 10th Asexual reproduction Asexual reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes and almost never changes the number of chromosomes. Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaebacteria, eubacteria, and protists. Many plants and fungi reproduce asexually as well.
Inbreeding is the production of offspring from the mating or breeding of individuals or
organisms that are closely related genetically.By analogy, the term is used in human
reproduction, but more commonly refers to the genetic disorders and other consequences that
may arise from expression of deleterious or recessive traits resulting from incestuous sexual
relationships and consanguinity. Inbreeding results in homozygosity, which can increase the
chances of offspring being affected by deleterious or recessive traits.This usually leads to at least
temporarily decreased biological fitness of a population(called inbreeding Common fruit fly
females prefer to mate with their own brothers over unrelated males. depression), which is its
ability to survive and reproduce. An individual who inherits such deleterious traits is colloquially
referred to as inbred. The avoidance of expression of such deleterious recessive alleles caused by
inbreeding, via inbreeding avoidance mechanisms, is the main selective reason for outcrossing.
Crossbreeding between populations also often has positive effects on fitnessrelated traits, but
also sometimes leads to negative effects known as outbreeding depression. However increased
homozygosity increases probability of fixing beneficial alleles and also slightly decreases
probability of fixing deleterious alleles in population. Inbreeding can result in purging of
deleterious alleles from a population through purifying selection.
Centres of diversity – types of biodiversity – Centres of origin – Law of homologous series – centers of origin – types of centres of diversity – gene sanctuaries – genetic erosion – main reasons of genetic erosion – extinction – introgression – gene banks – types of gene banks
This P.P.T is about a chapter reproduction in 10th Asexual reproduction Asexual reproduction is a type of reproduction by which offspring arise from a single organism, and inherit the genes of that parent only; it does not involve the fusion of gametes and almost never changes the number of chromosomes. Asexual reproduction is the primary form of reproduction for single-celled organisms such as the archaebacteria, eubacteria, and protists. Many plants and fungi reproduce asexually as well.
Heterosis breeding
Heterosis or hybrid vigour or outbreeding enhancement
Types of heterosis
Genetic basis of heterosis
HYBRIDS
Development of inbreds
Combining ability
Types of hybrids
Single cross hybrid
Double cross hybrid
Triple cross hybrid
Top cross hybrid
HYBRIDIZATION & HAPLOID PRODUCTION
Introduction
WIDE HYBRIDIZATION
INTER-SPECIFIC HYBRIDIZATION
Barriers to distant hybridization
Techniques to overcome barriers
Haploids and Doubled Haploids in Plant
Production of haploids and doubled haploids
a) Induction of maternal haploids
Wide hybridization
3. In vitro induction of maternal haploids – gynogenesis
Induction of paternal haploids – Androgenesis
Production of Homozygous Diploid Plants
Application of Haploids in Plant Breeding
Importance and Implications of Anther and Pollen Culture
While asexual reproduction only involves one organism, sexual reproduction requires both a male and a female. Some plants and unicellular organisms reproduce asexually. Most mammals and fish use sexual reproduction. Some organisms like corals and komodo dragons can reproduce either sexually or asexually. But in the long term (over several generations), lack of sexual reproduction compromises their ability to adapt to the environment because they do not benefit from the genetic variation introduced by sexual reproduction.
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