Self Incompatibility Barriers
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This document discusses self-incompatibility in plants. It begins by defining self-incompatibility as the inability of a plant's pollen to fertilize itself or other flowers on the same plant. The document then classifies self-incompatibility into heteromorphic and homomorphic types. Heteromorphic self-incompatibility is associated with flower morphology and includes distyly and tristyly. Homomorphic self-incompatibility includes gametophytic and sporophytic systems, which differ in whether compatibility is determined by the pollen or plant genotype. The document provides examples and limitations of self-incompatibility.
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Self incompatibility in Plants
This document provides information about self-incompatibility in plants. It begins by defining self-incompatibility as the inability of a plant's pollen to fertilize itself or other flowers on the same plant. The document then discusses the types of self-incompatibility, including heteromorphic (distyly and tristyly) and homomorphic (gametophytic and sporophytic). It provides examples of how self-incompatibility is inherited in different systems. The document also covers the importance of self-incompatibility in plant breeding and some methods to eliminate or suppress self-incompatibility.
Self incompatibility
This document discusses self-incompatibility in plants. It begins by defining self-incompatibility as the prevention of fertilization after self-pollination. There are two main types of self-incompatibility systems - homomorphic and heteromorphic. Heteromorphic systems involve morphological differences between flowers like distyly seen in Primula, while homomorphic systems do not. Homomorphic systems include gametophytic and sporophytic self-incompatibility, which differ in how the incompatibility reaction is controlled. Self-incompatibility promotes outbreeding and maintains genetic diversity in plant species. It has applications for plant breeding through hybrid seed production.
Self incompatibility in Plants
Self-incompatibility refers to the inability of a plant with functional pollen to set seeds when self pollinated. It is the failure of pollen from a flower to fertilize the same flower or other flowers of the same plant.
This presentation includes, Single-locus self-incompatibility- {Gametophytic self-incompatibility (GSI) and Sporophytic self-incompatibility (SSI)},2-locus gametophytic self-incompatibility, Heteromorphic self-incompatibility,Cryptic self-incompatibility (CSI) and Late-acting self-incompatibility (LSI).
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1) Apomixis is a form of asexual reproduction that occurs in some plant species and can fix heterosis in hybrids. It allows for the production of seeds that are genetically identical to the parent plant.
2) There are different types of apomixis that occur, including apospory and diplospory. Apomixis is detected by a failure to obtain hybrid plants from crosses and uniform progeny from heterozygous plants.
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This document discusses self-incompatibility in plants. It begins by defining self-incompatibility and providing examples of plants that exhibit this trait. It then describes the different types of self-incompatibility, including those based on flower morphology (heteromorphic vs homomorphic), genes involved (monoallelic, diallelic, polyallelic), site of expression (stigmatic, stylar, ovarian), and pollen cytology (binucleate, trinucleate). The document also covers the physiological mechanisms of self-incompatibility and its importance for plant breeding through promoting outcrossing and facilitating hybrid seed production.
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This document provides information about self-incompatibility in plants. It begins by defining self-incompatibility as the inability of a plant's pollen to fertilize itself or other flowers on the same plant. The document then discusses the types of self-incompatibility, including heteromorphic (distyly and tristyly) and homomorphic (gametophytic and sporophytic). It provides examples of how self-incompatibility is inherited in different systems. The document also covers the importance of self-incompatibility in plant breeding and some methods to eliminate or suppress self-incompatibility.
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This document discusses self-incompatibility in plants. It begins by defining self-incompatibility as the prevention of fertilization after self-pollination. There are two main types of self-incompatibility systems - homomorphic and heteromorphic. Heteromorphic systems involve morphological differences between flowers like distyly seen in Primula, while homomorphic systems do not. Homomorphic systems include gametophytic and sporophytic self-incompatibility, which differ in how the incompatibility reaction is controlled. Self-incompatibility promotes outbreeding and maintains genetic diversity in plant species. It has applications for plant breeding through hybrid seed production.
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Self-incompatibility refers to the inability of a plant with functional pollen to set seeds when self pollinated. It is the failure of pollen from a flower to fertilize the same flower or other flowers of the same plant.
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Mode of pollination is very important in plant breeding because it determines the genetic constitution, nature of gene action, ease in pollination control and stability of varieties after release. There are several mechanisms that promote cross pollination, among these self-incompatibility. Self incompatibility is defined as the prevention of fusion of fertile (functional) male and female gametes of the same plant (Gowers, 1989). Self incompatibility is a system where self-recognition and rejection is the rule that prevents inbreeding depression.
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Self incompatibility(SI) in plant plays important role in view of hybrid seed production. SI in this ppt have been explained in detail from its basics. The mechanism has been explained on the basis of conventional methods and molecular basis. It will be very useful for teaching and students.
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Clonal selection
Clone is the progeny of a single plant, produced by asexual reproduction
Clonal selection is the selection of the most desirable members of a clone for continued vegetative propagation rather than for sexual reproduction.
The members of a clone keep up genetic constancy.
So by clonal selection and continued vegetative propagation, the desirable qualities of plants can be maintained for long.
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- Autopolyploids are produced through chromosome doubling within a species, such as through meiotic errors or chemical treatment. This results in organisms with 3, 4, 5, etc. copies of the genome.
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ABC MODEL
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Sexual reproduction in flowering plant
Flower structure and development of male and female gametophytes in flowering plants are specially designed for fertilization. A flower has parts like pedicel, thalamus, sepals, petals, stamens and carpels. In the anther, microsporogenesis produces haploid pollen grains which develop into male gametophytes with two sperm cells. In the ovule, megasporogenesis and megagametogenesis lead to formation of the female gametophyte consisting of seven cells including the egg cell. Pollination, whether self or cross, transfers pollen for fertilization through pollen-pistil interaction where compatible pollen tubes deliver the sperm for double fertilization
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Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
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Self Incompatibility Barriers
- 1. PBG 301 – FUNDAMENTALS OF PLANT BREEDING (2+1) BARRIERS TO SELF – INCOMPATIBILITY Presented By… Guhan.C, B.Sc.(Hons).Agri, Id. No : 2018033029, JKKMCAS, Erode.
- 2. SELF-INCOMPATIBILITY (SI) • It refers to the inability of a plant with functional pollen to set seeds when self pollinated. • It is the failure of pollen from a flower to fertilize the same flower or other flowers of the same plant. • It prevent self-fertilization and thus encourage out-crossing and allogamy.
- 3. General features of Self-incompatibility… Prevent selfing and promotes out-breeding so increases the probability of new gene combinations. Causes may be morphological, physiological, genetical or biochemical. Normal seed set on cross pollination. May operate at any stage between pollination and fertilization. Reduces homozygosity.
- 5. Heteromorphic self-incompatibility… • The genes responsible for self incompatibility in heterostylous flowers are strongly linked to the genes responsible for flower polymorphism, so these traits are inherited together. • The associated concepts are distyly and tristyly Heteromorphic self incompatibility is associated with flower morphology
- 6. Distyly… • Stamens - low and high. • Styles - short and long. • It is determined by a single gene, with two alleles. • The flower with short style and high stamen is called as thrum type • Flower with long style and low stamen is called as pin type.
- 8. Tristyly… • In tristyly, styles and stamens have three different positions. • It is determined by two genes S and M, each with two alleles. S gives rise to short style, S and M to medium style s and m to long style. • The no. of. possible genotypes is greater.
- 10. HOMOMORPHIC SELF- INCOMPATABILITY In Homomorphic self-incompatibility all the flowers have same structure. 1) GAMETOPHYTIC SELF- INCOMPATIBILITY. 2) SPOROPHYTIC SELF INCOMPATIBILITY GAMETOPHYTIC SELF- INCOMPATIBILITY… This type was first described by East and Mangeldorf in 1925 in tobacco. In this system, the incompatibility is determined by the genotype of the pollen and not by the genotype of the plant on which it is produced.
- 11. • The S loci are extremely polymorphic (there is an abundance of multiple alleles) in the population. • Incompatibility is controlled by the single S allele in the haploid pollen grain. • Thus a pollen grain will grow in any pistil that does not contain the same.
- 13. SPOROPHYTIC SELF INCOMPATIBILITY • This type was first reported by Hughes and Babcock in 1950 in Crepis foetida. • In this system incompatibility reaction of pollen is governed by genotype of plant on which pollen is produced, and not by genotype of pollen.
- 14. • Pollen will not germinate on the stigma (diploid) of a flower that contains either of the two alleles in the sporophyte parent that produced the pollen. • This holds true even though each pollen grain contains only one of the alleles. • For example, the S2 pollen, which was produced by a S1 S2 parent, cannot germinate on an S1 S3 stigma. • Order of dominance S1>S2>S3>S4
- 15. Limitations… 1. It is very difficult to produce homozygous inbred lines in a self incompatible species. 2. Bud pollination has to be made to maintain the parental lines. 3. Self incompatibility is affected by environmental factors such as temperature and humidity. Incompatibility is reduced or broken down at high temperature and humidity. 4. There is a limited use of self-incompatibility due to problems associated with the maintenance of inbred lines through hand pollination as it is tedious and costly.