水稻 葉綠素突然變異의 分離異常

Irregularities in the Segregation of Chlorophyll Mutation in the Irradiation of Dormant Rice Seeds

Dormant seeds of rice variety Jinheung were X-rayed and the segregation of chlorophyll mutants in M₂ and M₃, the ratio of fixed vs segregating lines in M₂, and the trend of ratio of fixed vs segregating lines among M₁ tillers were examined and also discussions were made on the cause of occurence of recessive-deficit in M₂ and later generation. Segregation ratios in M₂ and M₃ were 0.15 and 0.21 respectively, indicating recessive-deficit in both generations. The degree of deficit varied with the mutant lines. Certain lines were nearly fit to the expected ratios while others were either deficit or excessive. The ratios of fixed vs segregating lines in M₂ also varied with the mutant Lines as was in segregation ratio, and were not fit to the expected ratios. No definite trend was observed in the changes of ratio of fixed vs segregating lines in M₂ generation among the M₁ tillers. To speculate the size of mutated sector of M₁ panicle or the number of initial cells in the seed embryo which could form later the sporogenous tissue of M₁ panicle simply by the M₂ segregation ratio seemed far from accurate.