What is Apomixis? Give its importance

Explanation

Although seeds, in general are the products of fertilisations a few flowering plants such as some species of Asteraceae and grasses have evolved a special mechanism to produce seeds without fertilisation called apomixis.
Thus apomixis is a form of asexual reproduction that mimics sexual reproduction. There are several ways of development of apomictic seeds. In some species the diploid egg cell is formed without reduction division and develops into the embryo without fertilisation. More often, as in many Citrus and Mango varieties some of the nucellar cells surrounding the embryo sac start dividing protrude into the embryo sac and develop into the embryos. In such species each ovule contains many embryos. Occurrence of more than one embryo in a seed is referred to as polyembryony. In haploid apomixis, the development of embryo takes place from parthenocarpic egg cell embryo developing this way is naturally haploid. By squeezing seed of orange each seed has embryos of different sizes and shapes.
Importance of Apomixis: Hybrid varieties of several food and vegetable crops are being extensively cultivated. Cultivation of hybrid has tremendously increased productivity. Hybrid seeds have to be produced every year. If the seeds collected from hybrids are sown, the plants in the progeny will segregate and do not maintain hybrid characters. Production of hybrid seeds is costly and hence the cost of hybrid seeds became too expensive for the farmers. If these hybrids are made into apomicts, there is no segregation of characters in the hybrid propgeny. Then the farmers can keep on using the hybrid seeds to raise new crop year and he does not have to buy hybrid seeds every year. Due to the of the importance of apomixis in hybrid seed industry, active research is going on in many laboratories around the world to understand the genetics of apomixis and to transfer apomictic genes into hybrid varieties.