5 Most Important Advantages of Gene Recombination in Crop Improvement

The following are some of the advantages of gene recombination in crop improvement.

(a) Production of new varieties:

New varieties of plants that are not present in nature can be produced by the introduction of new genes.

(b) Somatic hybridization:

Two crop plants with important characters, which could not be hybridized sexually due to genome incompatibility, can be hybridized through protoplast fusion. Production of Pomato (Tomato x Potato) is one such example.

(c) Increasing photosynthetic efficiency:

Ribulose diphosphate carboxylase (Rubisco) is a key enzyme in the dark fixation of CO₂ Modification of Rubisco to reduce photorespiration (Osmond 1981) by elimination of oxygenase activity would increase-the C0₂ fixation rate.

The enzyme has two sub units and is known to be coded by seven genes. If these genes could be altered, resulting in the changed Rubisco, it will increase the photosynthetic efficiency.

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(d) Nitrogen fixation:

The roots of leguminous plants normally possess nitrogen fixing nodules, induced by various strains of Rhizobiumm.

As a result; leguminous plants require little or no nitrogen fertilizer. Arable crops require about 100 kg of nitrogen per hectare.

If this can be replaced by N₂ fixing genes, it would lead to a lot of saving in terms of fertilizer cost. Nitrogen fixation is catalyzed by the ATP dependent electron reduction of dinitrogen to ammonia by nitrogenase.

If it is possible to introduce the gene to higher plants, it would bring about a revolution in agriculture. This may be achieved by one of the following ways.

1. Transfer of nitrogen fixing gene (nif) from the living bacteria like Klebsiella, Azatobacter etc., to higher plants. This would enable the plants to fix the N₂ directly. This is still in the experimental stage, as the nitrogenase, produced by the nif gene, is highly oxygen Habile and gets degraded in higher organisms.

2. Expansion of host range of symbiosis to crops other than legumes. At present non leguminous plants do not have symbiosis with Rhizobium. If it is possible to expand the host range for the bacteria, a lot more plants will have the capacity of N₂ fixation.

3. Increasing the efficiency of symbiotic bacteria to N₂ fixation. By gene manipulation, it may be possible to increase the N₂ fixing capacity of the symbiotic bacteria, which will benefit the plants.

(e) Herbicide resistance, disease resistance etc:

By gene manipulation, it will be possible to introduce this character into plants.

In conclusion it may be said, that genetic engineering is a highly potential tool by which man can alter the macromolecule of inheritance and thereby change the biological environment to his choice.

But the new technique has to be used judiciously; otherwise it can also create untold harm to human society, if unscrupulous scientists use it to create destructive genes. A few of the specific applications of genetic engineering are discussed below in some detail.