Biotechnology for crop Improvement

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11 Δεκ 2012 (πριν από 4 χρόνια και 6 μήνες)

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Biotechnology for crop Improvement

G. Sabari nathan

Using the techniques of biotechnology, one or two genes may be transferred to

a highly developed crop variety to impart a new character that would increase its yield. There

are, broadly, three benefits to agriculture and crop-improvement programmes from use of

biotechnology. The first of these, the reduction of the duration of breeding programmes, makes

use of tissue culture. Plant tissue culture also allows creation of new genetic variation, from

which useful new varieties can be obtained. New methods of hybridization can be combined with

cell and tissue culture for selection of plants with desired traits. The third and most promising

benefit is from use of recombinant-DNA techniques. Transgenic plants, engineered for resistance

to diseases, pests and herbicides, and for better nutritional quality.

Biotechnology tools:

Functional genomics, Genetic engineering, Marker-assisted breeding

(MAS),Tolerance to abiotic stresses, Durable host-plant resistance, enhancing nutritional quality,

Nitrogen fixation in rice and Apomixis for hybrid seeds these are some of the biotechnology

tools for improving crop productivity and stability of production.
Abiotic stresses:
Abiotic stress is the most harmful factor concerning the growth and productivity of crops.

Abiotic stress can be overcome by transferring stress-induced genes to the crops. Some of the

genes responsible for exhibiting resistance to abiotic stress are as follows;
Stress-induced genes:
Heavy metal stress:

Aluminium induced

Metallothioneins

CUTA

Divalent cation tolerance protein
GENES ISOLATED FROM MANGROVES
Drought and Anaerobic:

Dehydrins

Alcohol dehydrogenase

Protein disulfide isomerase
Salt stress:

Ascorbate peroxidase

Catalase

Super oxide dismutase(SOD)

Glutathione peroxidase
Strategies to overcome abiotic stresses
:

Conventional plant breeding techniques have been used to develop new varieties able to produce

greater yields in spite of abiotic stresses.
The potential of biotechnology
:
In spite of the explosive development of biotechnology in the last 20 years, its use for obtaining

new abiotic stress
tolerant varieties has been very limited. The lack of basic scientific informa
-
tion of the molecular biology of crops is certainly the greatest constraint to the use of biotechnol
-
ogy for stress tolerance. Abiotic stress tolerance is the result of many genes expressed simultane
-
ously or in a certain order. Often this expression concerns plant architecture (roots, length of the

plant, leaf configuration) and complex physiological responses controlled by groups of genes. In

contrast to resistance to pests and insects, which can be obtained through modification of quite a

few genes, these traits will be much more difficult to modify. Modification of a complex of

genes is still beyond the possibilities of the current genetic engineering and transformation tech
-
nologies. But most important, very little is known about the molecular basis of important physio
-
logical and biochemical responses and characteristics of plants and animals.
Even if it is still early to expect biotechnology to contribute to practical production problems in

the area of stress tolerance, it is definitely making a great contribution to the understanding of the

plant physiology and biochemistry on the molecular and genetic level. Genetic engineering and

other biotechniques are being widely used to study the mechanisms responsible for stress toler
-
ance. This basic scientific research concentrates worldwide on drought, salinity and temperature

responses of plants on the molecular level.
MSSRF’s Anticipatory Research Programmes:
These programmes aims at developing location specific crop varieties offering resistance to

coastal salinity through identification of novel genetic combinations from the salt tolerant

mangrove species, generation of pre breeding material and integration of pre- and participatory

breeding framework

Delivering the lead talk on ''Ensuring and Enhancing Crop Productivity in

Response to Emerging abiotic Stress Conditions'' in the plenary session on ''Biotechnology'' at

the 97th edition of the Indian Science Congress, Dr Ajay Parida, Executive Director, M S Swami

Nathan Research Foundation (MSSRF) said India’s population is likely to reach 1.5 billion by

2030. There will be no option except to produce more and more from Diminishing per capita

arable land and irrigation water Resources and expanding abiotic and biotic stresses. We need to

double the food production, from the present 210 million tones to 420 million tones, within the

next 10 years. This will call for accelerated scientific efforts in the field of enhancing

productivity per unit of water, in coastal and inland areas under conditions of both water scarcity

and water salinity.
Dr Parida said the presence of salt content in soil increased because of over exploitation

of ground water, particularly in Punjab and Haryana. The MSSRF foundation had developed two

paddy seeds suitable to survive the salt and drought conditions by implanting the gene of

'Abrinna Marins'', a variety of mangrove and ''Abrinna Marins Ferrilian'', a plant found in

deserts, respectively. Outlining the challenges facing Indian agriculture like loss of cultivable

land, decline in water resources, loss of bio-diversity and forests, climate change and invasion of

trans-boundary pests; he said biotechnology could be an answer to them.
Appropriate targets for crop improvement:

Herbicide resistance

Insect resistance

Grain quality

Neutraceuticals

Virus resistance

Fungal resistance

Abiotic stress resistance
Green Agriculture:

Conservation farming

Integrated pest management

Integrated nutrient management

Quality Seeds

Enhanced resource utilization

Integrated natural resource management Systems

Biotechnology and Molecular Breeding.