Vol. 9 No. 1
Induced mutation- a tool for creation of genetic variability in rice (Oryza sativa L.)
Author(s): A. SHARMA AND S. K. SINGH
Abstract: The genetic variability in plants is getting narrowed due to human activities and natural calamities. Mutation is defined as sudden heritable change in a characteristic of an organism. Induced mutation is one of the potential tools for generating more variability which has been successfully exploited for improving several traits in many crop plants including rice (Oryza sativa L.). Rice is the world\'s leading food grain crop which serves as the main source of calories consumed by human being and occupies almost one-fifth of the total land area covered under cereals. The demand of rice is continuously increasing due to ever-growing population. To meet the growing demand, more variability is required to develop new high yielding varieties with tolerance to biotic and abiotic stresses. Use of induced mutation for improvement of rice received importance as a potential tool in the late sixties. A wide array of physical and chemical mutagens have been evaluated on rice and based on their relative efficiency and effectiveness, x-rays, γ-rays and fast neutrons (among physical) and EMS, nitroso methyl urea (NMU), sodium azide and ethidium bromide (among chemical) have been found useful for obtaining desirable mutants. Now, combination of both, chemical (EMS) and physical (γ-rays) mutagens are also being used which are giving encouraging results in creating variability and developing high yielding varieties. This method is generally being used for improvement of one or two simply inherited traits in otherwise well adapted and highly productive genotypes. The traits which have been induced in rice through mutation in the last five decades are; early maturity, short stature, more number of tillers, resistance to blast and leaf blight, resistance to lodging and cold, improved grain quality and higher yield. The present article gives an insight into the relevance of induced mutation in creation of genetic variability and development of outstanding rice varieties.
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