Title : Plant biotechnology and crop improvement
Ever since our forefathers have planted seeds, we have been utilizing natural genetic diversity created from spontaneous mutations and recombination for the selection of improved crops. These traditional methods have domesticated the species which we cultivate today and these methods resulted in developing large number of improved crop varieties. When the existing variability is exhausted or limited, plant breeders resorted to create variability by employing mutation breeding or hybridization.
Due to the development of green revolution varieties and its large-scale adoption, there was a rapid increase in agricultural output from significant increases in crop productivity. Between 1960 and 2000, yields for all developing countries rose 208% for wheat, 109% for rice and 157% for maize. Developing countries including India have shown the significant positive impact by cultivating these high yielding rice or whet varieties. Hybrid seed technology has also played a major role in improving agricultural production. Though we have attained self-sufficiency in food and agricultural production, we still need to increase crop production to meet the growing demand of world’s population. This warrants use of advanced technologies which are capable of accelerating genetic gains.
With improvement in our understanding of molecular biology, researchers are able to use DNA technology in crop improvement programs. Traditional plant breeding methods could be accelerated by increasing selection efficiency using marker-assisted selection (MAS) and genomic selection. It has been successfully demonstrated in maize that combination of biotech tools such marker-assisted selection and genomic selection using precision markers accelerated genetic gains by 2- to 3-fold. Using MAS technology, traits such as submergence tolerance, drought tolerance disease resistance in rice, heat tolerance and quality in wheat, disease resistance in soybean and potato have been improved. Simultaneous advancement in DNA sequencing and related bioinformatics tools led do development of innovative breeding platforms such as Nested Association Mapping, Multi-parent Advanced Generation Inter-Cross populations, genomic selection etc. and such technologies have been successfully employed in rice, maize and wheat.
To overcome the absence of genetic variability and problems arise due to linkage drag, researchers use recombinant DNA technology or transgenic technology to incorporate novel traits which are hitherto unavailable to crop plants. Transgenic crops expressing novel traits are popular among farmers and that these crops are being grown in an area of over 190 million hectares. The disadvantages which we have encountered in transgenic technology are addressed by genome editing technology which can make modification of genes or introgression of genes precisely, avoiding random mutations or position effect due to random integration of transgenes. Some of the products developed through this technology are considered transgene- free and are out-side the regulation. The commercialized products include genome edited mushroom and soybean.