Mutagenic effects of sodium azide in rice.

Seeds of rice cultivar M5 were presoaked in distilled water and treated for 2 or 3 hours with 0, 0.12, 0.50, 0.75, 1.0, 1.25, 1.50, and 1.75 mM sodium azide solutions prepared in 0.1 M phosphate buffer (pH 3). Criteria used to assess the biological effects of azide on rice were germination, seedling height, and seed sterility in the M/sub 1/ generation, and chlorophyll-deficient seedlings and viable mutations in the M/sub 2/ generation. In general, an increase in azide concentration, along with an increase in the post-treatment redrying period, resulted in a decrease in M/sub 1/ germination and seedling height. Azide treatment also induced sterility. The same treatment induced chlorophyll mutations in 98.5% of the M/sub 1/ panicle progenies and in 14% of the M/sub 2/ seedlings. The highest frequency of viable mutations scored in the adult plant stage was 4.64% on an M/sub 2/ plant basis. All azide concentrations were mutagenic.