水稻体细胞离体辐照无性系的变异特点

STUDY ON VARITATION IN RICE(Oryza sativa L. )SOMACLONES FROM IN VITRO IRRADIATED SOMATOCYTES

用粳稻品系ＳＨ（４８）作材料，以（６０）Ｃｏ－γ射线为辐照源，研究了水稻体细胞离体辐照无性系的变异特点。结果表明：高体辐照当代各性状的株间差异大多为生理效应，第二代恢复正常，故性状选择应从第二代开始。离体辐照能在离体培养的基础上成倍增加变异率和变异类型，但变异株系大多仅发生一种性状突变，部分这类突变受单基因，特别是隐性基因的控制。高体辐照的诱变效果，依材料、辐照剂量及性状而异。提高辐照剂量和选用合适的材料，可显著增加无性系的变异率，但辐照剂量高于４７．５Ｇｙ时，不利变异明显增多；本实验证明，用１９Ｇｙ的剂量处理幼穗较合适。离体辐照一般不改变原品种的基本特性，其后代在整体上能保持相对稳定和整齐一致，即使无性系内个别性状发生突变，其它性状也能保持供体品种的特征。因此，对于品种个别性状的改造，离体辐照可能比其它方法更有效。

The variation features of rice somaclones from somatocytes irradiated in vitro with 60 Co-γ rays were studied with the strain SH48derived from anther culture. The result showed that the character variations in the first generation of these somaclones were mainly physiological and most of them would recover normal in the second generation, thus the character selection for these somaclones should be begun from the second generation. In these varied somaclones there were usually one or two mutant characters and some of them were controlled by monogene, especially the recessive monogene. The effect of radiation on the variation was different with materials irradiated, dosages and characters observed. In case of increasing the dosage in certain range or using suitable materials irradiated, the variation frequency of somaclones would be remarkably raised, the dosage of 19Gy seems to be appropriate for irradiating young panicles. In a somaclone from in vitro irradiated somatocytes, even if some characters took mutation, the other characters would not be influenced; therefore the somaclones from irradiated somatocyte possessed a certain relative stability and would maintain the main features of donor variety. The method using in vitro irradiation seems to be more effective than conventional irradiation, tissue culture or backcross for improving a few characters in a variety.