APOMIXIS and POLYEMBRYONY
- Seeds without fertilization
- It is a form of asexual reproduction, which mimics sexual reproduction
Mechanism-
1. Megaspore mother cell (2n) -- mitosis -- megaspore (2n) -- female gamete (2n) -- embryo (2n)
2. Nucellus cells (2n) -- develop into embryo (2n)
Eg citrus
Here two embryo are formed,
First, by sexual reproduction,
Second, from nucellus.
More than one embryo - polyembryony.
USE-
- Hybrid - superior characteristics.
- But when, sexual reproduction -- segregation of characters, so they have to be produced every year -- costly for farmers
- But if, these hybrids are made apomicts, no sexual reproduction, no segregation of characteristics, they remain hybrid
- Research is going on.
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