Rice (Oryza sativa L.) is the most crucial cereal food crop of India, which occupies about 24% of gross cropped area of the country. It contributes 42% of total food grain production and 45% of total cereal production of the country.Thus rice production in India as well as in several other Asian countries must be doubled by the year 2025 to meet the requirement of the increasing population. The genetic classification of rice plant belongs to the genus Oryza of family Graminae (Poaceae). The Oryza genus is divided into four species complexes: O. sativa, O. officinalis, O. ridley and O....