空间条件对水稻恢复系诱变作用的研究I．早熟、丰产突变类型的筛选与观察

Studies on the Mutagenic Effects of High Space Conditions on Rice Restorer lines 1. Screening and Observation of Early maturing and High yielding Mutants

利用返回式卫星的空间条件搭载水稻恢复系明恢６３干种子，在海拔２１８～３２６ｋｍ的高空飞行１６６．２ｈ回收后种植，调查ＳＰ１、ＳＰ２代的性状表现，ＳＰ３代与其繁殖植的ＳＰ４代性状平均值的相关程度。结果表明：ＳＰ１代主要性状与ＣＫ差异不明显。ＳＰ２代群体的单株间９个主要农艺、经济性状变幅极差大，变异系数大，变异频率高；性状变异向有利和不利两个方向突变；部分性状的变异呈偏态分布，多向有利（增加）的方向发展；单株间出现早熟２０ｄ以上、大穗大粒等有利突变体。ＳＰ３代单株与其所繁殖ＳＰ４代的早熟、丰产的６个性状平均值，具有极显著的相关性。已筛选出４个比ＣＫ早熟ｌｌ～２ｌｄ、丰产的新品系，可作为恢复系选择材料。因此，水稻干种子在空间条件下所产生的变异是可以稳定地遗传的。

The dry seeds of Minghui 63,a strong rice restorer line,were carried by the recoverablesatellite under high space conditions of 218～326 km above the sea level for l66.2h. The treated seeds weresown so as to be observed on the character expression of seeds of the SP1 and SP2 generations and the correl-ative degree of characters between the individual plants in the SP3 generation and their off springs in theSP generation. The results showed that the main characters of the SPl generation were not obviously differ-ent from those of the control;9 main agronomic and economic characters of the individual plants in the SP2generation varied to a great extent with great variation coefficients and a high variation frequency; somefavourable mutants of early maturity(more than 20 d earlier) with large panicles and heavy grains were ob-served.It was also found that 6 characters such as early maturity, high yielding ability,etc. of the in-dividual plants in the SP3 generation were closely correlated with those of their off springs in the SP4 gener-ation,which indicated that the variations induced by high space conditions are heritable. 4 early maturity(11～2l d earlier than the control ) and high yielding strains were screened for the breeding of restorerlines。