Essay on the Role of Biotechnology in Agriculture
1. Production of pathogen – free plants:
Plants traditionally being vegetatively propagated are systemically infected with viruses and other pathogens which greatly reduce yield and also quality of the marketed commodity. Virus diseases like potato leaf roll virus (PLRV) or potato virus Y (P VY) for example, can cause upto 95% reductions in the tuber yield of potato crops. Increase in yield upto 300% (Averaging 30%) has been reported following replacement of virus – infected stock with specific pathogen free plants.
Since majority of viruses infect plants in a systemic manner their elimination may be achieved through meristem tip culture.
2. Production of Disease Resistant Plants:
This is one of the most useful applications of tissue culture in crop improvement. In potato, somaciones have been screened for both late and early blight resistance. In maize, somaclonal variation has induced resistance to race T of southern corn leaf blight. In sugarcane, resistance to diseases like Fiji and downy mildew have been recovered. In lucerne, selection of cell lines and plants resistant to the toxin of Fusarium oxysporium has been accomplished.
3. Improvement of nutritional quality:
One of the major sources of protein for human and animal consumption is constituted by the proteins contained in seeds of many plant species. The cereals and legumes which are major sources of storage seed proteins, contain limited amount of certain amino acids which are essential for human beings. Majority of these cereals are deficient in lysine whereas legumes are deficient in sulphur amino acids. A wide range of approaches have been employed for improving nutritional quality of various crop plants. Important among them are selecting cell lines resistant to amino acid or their analogues of lysine, tryptophan, proline and phenylalanine. Isolation of variants over producing specific amino acids in culture hni been successful, but expression in the whole plant and especially in Lhe seed has not yet reached the ievel required to make an impact on protein quality.
4. Selection for salt and drought tolerance:
Continued efforts to increase intensity of cropping for increasing production from limited land resource by extending irrigation facilities have resulted in the gradual build-up of salt concentrations in the soil. This has resulted in loss of productivity on such soils.
Salt tolerant lines have been produced in crop plants such as tobacco, tomato, cereals. Salt tolerance has been incorporated into rice lines with improved plant type. Some of the improved rice cuitivars viz., IR 42, 1R 43 and IR 52 are salt tolerant.
Development of cuitivars tolerant drought can contribute significantly in agriculture economy. Tolerance to drought is a polygenic trait and involves highly complex osmo-regulatory functions. In tissue cultures, simulated drought conditions have been achieved through incorporation of non-penetrating osmotic solutes such as PEG (polyethylene glycol) and dextrans in the media.
5. Production of Genetically variable plants:
The success of any crop improvement programme depends on the usable genetic variability in the base population cells in culture offer an excellent systems for inducing variations and regenerating pure mutant types. Genetic variation can be an option to lessen our reliance on cost intensive germ-plasm collection and conservation programmes. Variant producing capacity of cell culture can be augmented to a great extent by employing physical and chemical mutagens. Somaclonal variation has been extensively exploited for the improvement of a sexually propagated crops viz., potato, sugarcane. From cell cultures, some superior cuitivars have already been produced in sugarcane which are high yielding, drought resistant and temperature tolerant.
Molecular nitrogen in the atmosphere is converted into biologically converted forms by nitrogen fixing micro-organisms e.g. Rhizobium. The most sophisticated approach to biofertilization is to create plants that possess the genetic capacity for nitrogen fixation. Attempts are being made to transfer genes for nitrogen fixation (hifgenes) from bacteria to plants.
7. Rapid clonal propagation:
Tissue culture has found its best commercial application in production of cloned plants at a very high rate as compared to conventional methods. It is important specially for initially building up of propagation stock of elite clones or individual plants which are otherwise slow to multiply. A number of agriculturally important plants have been clonally multiplied.
8. Germplasm storage:
The primitive cultivars and wild relatives of crop plants constitute a pool of genetic diversity which is invaluable for further breeding programmes. There are over 20,000 plant species which are rare or threatened with degradation of their neutral habitats. The most economical form of storing genn plasm for seed propagated species is seeds. However, there are certain limitations of this method. Therefore, various methods of invitro storage of germplasm are thus of great practical significance for long term storage of germplasm. Presently, there are two approaches to invitro germ plasm storage. Slow growth technique and cryopreservation.
9. Biological control of Agricultural pests:
Insects consume nearly one-third of human food supplies on earth. One of the major goals of biotechnology is to develop target specific biological pesticedes that will kill some specific pest but will not harm other species. Several insect- specific pathogens, developed through biotechnological processes, are being produced commercially for their use as microbial pestices. Bacillus thuringienis inocula have been used as bio-insecticides. Toxin produced by the bactenium kills the gypsy moth. The prevention of crown gall disease formation is achieved by spraying young plants or seeds avirulent species Agrobacterium radiobactor var, radiobactor. Microbial insecticides have a number of advantages over traditional chemical insecticides.
(a) They are specific for a small number of species of insects and do not kill plants, animals and beneficial insects.
(b) They are cheaper than organic pesticides and
(c) They do not leave any residue effect.
Can be effectively used to increase storage of food grains, increase nutrition value of food, enhance flavour etc. Fermented food through enzyme engineering (beer biotech).
In Health and Medicine:
i. Through human genetics, identification of defective genes, and gene therapy.
ii. In forensic medicine, identification of parents, criminals etc. by finger printing.
iii. Various vaccines are either produced or expected to produce eg: Rabies, Malaria, Hapatitis B, Cholera.
iv. Various vital ingredients like Insulin, Interferons can be produced. Also antibiotics like, penicillin, streptomycin etc.
Production of high fructose corn syrup – sweetening agent for soft drinks, enhance the production of alcohol, production of chemical from agri waste.
i. Special Bacterial to eat away oil spilling by digesting Hydro Carbon.
ii. Bio-tech developed oragnisms to act as bio indicators to indicate level or pollution in environment.