Use of somatic embryogenesis in crop improvement

Use of somatic embryogenesis in crop improvement:-

1. Large-scale propagation:-

> Depending on the plant species, virtually unlimited numbers of embryos can be generated from a single explant.

> Drew (1980) estimated that one liter of a carrot suspension culturecontained 1.35 million somatic embryos. Thus, in comparison toconventional propagation methods (e.g., rooted cutting, grafting)

and other in vitro regeneration method (e.g., organogenesis), somatic embryos offer better potential for large-scale propagationsystems. 

> Even greater economies of scale may be possible if bioreactor and continuous culture technologies can be applied to embryogenic systems.

> Production of synthetic seeds by encapsulating somatic embryos, shoot buds or any other meristmatic tissue. 

> Scope of Synthetic Seeds:-

i. Propagation:-

- Rare and Endangered Plants.

- Elite Genotype.

- Genetically Engineered Plants.

- Seedless Plants.

- Commercially important plants.

ii. Conservation:- Long and Short Term Storage.

iii. Transport:- 

- Exchange of Axenic Plant.

- Material Free of Undesirable Contaminants. 

2. In vitro selection:-

> In vitro culture of plant cells, tissues or organs on a medium containing selective agents offers the opportunity to select and regenerate plants with desirable characteristics. The technique has also been effectively utilized to induce tolerance which includes the use of some selectiveagents that permit the preferential survival and growth of desired phenotypes

> The presence of a selective agent in the embryogenesis induction or callus initiation medium could increase the probability of recovering stress tolerant plants through somatic embryogenesis.

i. NaCl     =    Salt tolerant

ii. PEG or mannitol     =    Drought tolerant

iii. Phytotoxin i.e. fusaric acid or culture filtrate or Pathogen it self      =    Disease resistant

3. Genetic transformation:- Due to its potentially high multiplication rates andpotential for scale-up via bioreactor, somatic embryogenesis has been emphasized as a suitabletarget for gene transfer.

Conclusion:- Somatic embryogenesis has offered the opportunity to develop an efficient propagation system in a large no. of angiospermic and gymnospermic plants. Micropropagation through somatic embryogenesis has many advantages over conventional vegetative propagation and its commercial use in horticulture, agriculture and forestry is currently expanding worldwide. Somatic embryogenesis could also applied in a variety of applications like in vitro conservation, genetic transformation, development of stress-tolerant plants etc.