Abstract:  A brittle culm mutant w7bc5 was obtained from japonica rice wyj7 by heavy ion irradiation. The fertility and thousand-seed weight of w7bc5 mutant reduced, while other agronomic characters changed slightly. The w7bc5 mutant showed 29.8% less breaking-resistant strength and 26.7% less cellulose content compared to wild type plant, while hemi-cellulose increased evidently, no significant difference has been found in contents of lignin and SiO2. Results from analyzing soluble sugar contents of w7bc5 and wild type showed a 12.8 mg/g difference during heading stage, which further extended to 62.9 mg/g. 

Key words: rice, brittle culm mutant, cell wall, cellulose, soluble sugar content