Variations of Internode Length and Other Characters in Induced Long-Culm Mutants of Rice

Variations in culm length and some agronomic characters of eight induced long-culm mutants of Norin 8 were investigated. Six mutants showed a significant increase in the culm length at the 1% Ievel and two mutants at the 5% Ievel. All mutants differed from the control in the patterns of internode length. Based on the percentage contributions of internode length and number of internodes to culm length, the mutants were classlfied mto four types The first rs an "upper elongation" type, in which the percentage contribution of the first and the second internodes to the culm length is more than that of the control The second Is a "lower elong Ition" type, in which two upper internodes contribute to the culm length less than the control The thrrd Is a "multl nodes" type, in which the change of culm length depends on an increase in the internode number. The fcurth is a "normal" type, in which the increase in culm length owes to slight increases of all the respective internode lengths. The long-culm mutants differed from the original cultivar in three or more agronomic characters examined.