Gamma rays induced mutations in Basmati rice (Oryza sativa L.).

摘要

Observations were made on the seedling growth injury and spikelet sterility in M1 generation and chlorophyll and morphological mutations in M2 generation in Basmati rice (Oryza sativa) induced by gamma rays. Dry seeds (12% moisture) of two rice cultivars, Taraori Basmati and Pusa Basmati 1, were used for mutagenic treatments. Some 200 seeds were taken for each treatment of gamma rays in both cultivars for mutagenic treatment. Seeds were exposed to 50, 100, 150, 200, 250 and 300 Gy doses of gamma rays. Some 15 types of morphological mutants in Taraori Basmati and 13 types in Pusa Basmati were identified. These mutants were dwarf, semidwarf, tall, early maturing, late maturing, high tillering, large panicle, partial sterile, complete sterile, bushy, pigmented pericarp, red kernel, large grain, awned, awnless, pigmented, awn, and high yielding. No relationship between treatment doses and mutation spectrum was established. Morphological mutants showed independent dose relationship with the mutagenic treatments as they occurred at random. The frequency of morphological mutants per 100 M2 plants in case of Taraori Basmati was highest at 200 Gy gamma rays (1.64%) and in Pusa Basmati 1 (1.57%). The high yield of the mutants was not due to only one trait but due to a cumulative effect of all yield attributing traits. Induction of useful mutants such as dwarf, semidwarf, earliness and high yielding derived from both cultivars could be of immense significance for the Basmati rice improvement programme..