Apomixis, Polyembryony & Parthenocarpy in Fruit Crops
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Apomixis, Polyembryony & Parthenocarpy in Fruit CropsApomixis / Apomictic Seed / Abnormal Sexual ReproductionDevelopment of embryo without meiosis and fertilization.
Term: Hacke (1893).
Discover: Winkler (1908).
Types
Development of embryo without meiosis and fertilization.
Term: Hacke (1893).
Discover: Winkler (1908).
Types
1. Obligate Apomixis
Malus sp.
2. Apospory
Malus.
3. Saprophytic Agamospermy
Mango, citrus.
Maheswary (1950) Classified Apomixis
1. Recurrent
Malus, raspberry.
2. Non-recurrent
3. Adventition / Nucellar Embryony / Nucellar Budding
Citrus.
4. Vegetative Apomixis
ParthenogenesisDevelopment of embryo from egg cell without fertilization.
E.g.: Mangosteen, strawberry.
PolyembryonyTwo or more embryo are produced in a seed is called as polyembryo.
Some time more than one nucellus develops within the embryosac which may lead to the development of more than one embryo.
Term: Brau (1859).
First time discovered: Leeuwenhoek (1979) in Citrus aurantium.
Types
Development of embryo from egg cell without fertilization.
E.g.: Mangosteen, strawberry.
Two or more embryo are produced in a seed is called as polyembryo.
Some time more than one nucellus develops within the embryosac which may lead to the development of more than one embryo.
Term: Brau (1859).
First time discovered: Leeuwenhoek (1979) in Citrus aurantium.
Types
1. Nucellur / Adventitive Seedling
First time Strangburg in 1978.
Appear in the maternal tissue of the ovary.
Pollination is needed to trigger the growth of nucellur seedling.
Nucellur begain to developed as soon as the pollination occurs where as zygotic embryonic where as the development.
Citrus (C. unshiu – 40 seedling), mango, jamun, mahua.
2. Cleavage Polyembryony
Coconut.
3. Zygotic Seedling / Gametic Seedling
Develop of seedling from zygotic embryo.
Detection of PolyembryonyUniform of height.
Cotyledon colour – identical to male parents.
Browning – (polyphenol oxidase) when the terminal shoot is crushed a homogenate colour indicates.
ParthenocarpyDevelopment of fruit without fertilization.
Term: Null (1902).
Types
Uniform of height.
Cotyledon colour – identical to male parents.
Browning – (polyphenol oxidase) when the terminal shoot is crushed a homogenate colour indicates.
Development of fruit without fertilization.
Term: Null (1902).
Types
1. Natural Parthenocarpy
Development of seedless due to genetic sterility.
E.g.: Banana, pineapple, Japanese persimmon.
2. Vegetative Parthenocarpy
Banana, pineapple.
3. Facultative Parthenocarpy
Seedless due to environmental stimulation.
E.g.: Grape, citrus.
4. Stimulative Parthenocarpy
Grape variety Black Corianth.
StenospermocarpyFruits are developed normal fertilization but abortion of embryo.
Term: Stout (1936).
Grape (Thompson Seedless).
Origin of grape stenospermcarpy: Cultivar Sultania and Black Monukka.
OvarySimple Carpal: One carpel present in the flower. E.g.: Avocado, peach and date palm.
Compound Carpal: More than two carpals in the pistil. E.g.: Apple, orange etc.
Types of Ovary
Fruits are developed normal fertilization but abortion of embryo.
Term: Stout (1936).
Grape (Thompson Seedless).
Origin of grape stenospermcarpy: Cultivar Sultania and Black Monukka.
Simple Carpal: One carpel present in the flower. E.g.: Avocado, peach and date palm.
Compound Carpal: More than two carpals in the pistil. E.g.: Apple, orange etc.
Types of Ovary
1. Hypogynous
Floral parts arising from below the ovary.
Ovary is superior.
E.g.: Grape, orange, persimmon, avocado etc.
2. Epigynous
Floral part arising upon the ovary.
Ovary inferior.
E.g.: Banana, apple, pear, cranberry, quince.
3. Perigynous
Floral parts arising the ovary, ovary half inferior.
E.g.: Peach, apricot, almond and cherry etc.