Improvement of Horticultural Crops against Abiotic Stresses: A Strategic Approach

Abiotic stress factors impose a major threat to agriculture. Therefore, the efforts to develop stress tolerant plants are immense of importance to increase crop productivity. The classical breeding programme are being used to integrate genes into the crop to induce stress tolerance. However, in many cases, it has failed to provide desirable results. In recent years, tissue culture based in vitro selection has emerged as a feasible and cost effective tool for developing stress tolerant plants. Plants tolerant to abiotic stress can be acquired by applying the selection agents such as NaCl (for salt tolerance) and PEG or mannitol (for drought tolerance) in the culture media. Only the explants capable of sustaining such environments survive in the long run are selected. In vitro selection is based on the induction of genetic variation among cells, tissues and organs in cultured and regenerated plants. The selection of somaclonal variations appearing in the regenerated plants may be genetically stable and useful in crop improvement. In this paper, the progress made towards the development of abiotic stress tolerant plants through tissue culture based approaches is reviewed.