Use of radioisotopes in agriculture: DNA based molecular markers in crop improvement

Agriculture has always benefited from the use of radioisotopes in many ways. In the beginning radioisotopes were mostly used for physiological studies to measure photosynthetic efficiency, nutrient uptake, and for mutation breeding. Radioisotopes have now become a part of the biotechnological tools that are being increasingly used in improving crops and production systems. The tools of biotechnology are being increasingly used to hasten breeding and address problems of biotic and abiotic stresses. Some of the non-radioactive methods have replaced radiotracer techniques and thus led to automation often at high cost. However, still there remain many applications where radioisotopes seem almost indispensable. For some of the applications like comparative genome mapping, the confirmation of transgenics, and establishment of gene copy number, use of RFLP with radioisotopes is essential. The following research areas at ICRISAT use radioisotopes: (1) physiological basis of adaptation to abiotic stresses (ii) development and use of appropriate DNA markers crop improvement; (iii) characterization of cytoplasmic male sterile systems and genetic diversity of breeding materials, land races and the wild relatives and (iv) molecular basis of disease resistance; (v) comparative genome mapping across cereals, (vi) isolation and characterization of genes of potential value to genetic improvement and (vii) verification of genetic transformation events. (author)