Abstract:Brittle culm mutants are suitable materials to study the mechanism of secondary cell wall formation. A britlle culm and leaf mutant (bc9311-1) was obtained from M2 population of indica rice 9311 by ion beam irradiation. The fertility and tiller number of bc9311-1 mutant reduced observably, while other agronomic characters changed slightly. Cell wall components analysis showed that cellulose content of mutant leaf and culm decreased sharply, while hemi-cellulose increased evidently, no significant difference has been found in contents of SiO2 in leaf. Genetic analysis showed that the mutated phenotype of bc9311-1 was controlled by a recessive gene. The bc9311-1 gene was mapped on rice chromosome 1 by using a F2 population developed from a cross between the mutant and 02428, and the genetic distances from the gene to the linked SSR markers RM1095 and RM3632 were 0.6cM and 3.4cM, respectively.. The above results laid the basis for the research of the fragile and dwarf mutant and its gene cloning.