IDENTIFICATION OF RICE MUTANTS (Oryza sativa L.) FOR AGRONOMICAL AND ROOT SYSTEM TRAITS

Abstract

Mutation techniques are very important tools to study genetic variability, function, action and regulation of genes. Moreover, in plant breeding the root system is traditionally selected in an indirect way. In this paper we propose the use of mutation techniques to directly select mutants affecting root morphophysiological traits for future mapping and cloning of the genes involved. After preliminary tests to identify the best radiation dose, 2,500 and 3,500 seeds from cultivar Taim, indica sub species, were irradiated with doses 200 Gy and 250 Gy, respectively, and grown in a protected area. After harvesting, M2 seeds were dried, stored and plantlets were evaluated in hydroponic culture, aiming to identify potential root mutants. The dose of 200 Gy seems to be associated with increases in number of seminal roots. From 9,737 seeds evaluated we selected 623 putatively root mutants. Moreover, we selected plants with high and low number of seminal roots. Which can be important to evaluate the root effect on plant establishment. The root mutants described will be available to the scientific community through the rice mutation club / FAO / IAEA after their proper confirmation and characterization.