云南粳稻核心种质杂种后代孕穗期耐冷性研究

Research on cold tolerance at booting stage of the hybrids of Japanica with core collection for rice landrace in Yunnan

以236份云南地方粳稻核心种质和云南主栽粳稻Oryza satica品种合系35配制的杂种F5、BC1F4、BC2F3和BC3F2为材料,在昆明自然低温平均17.8℃(冷害)条件下,对亲本及其后代进行孕穗期耐冷性研究。结果表明:①亲本耐冷性状间的相关性明显高于其杂种后代,不同世代间总体趋势为随着回交世代增加其性状间相关性减弱。在亲本及其杂种后代间耐冷指标性状穗颈长、穗下节长、每穗实粒数、每穗秕粒数与结实率均呈较高的(≥0.370)极显著(n=236,R0.01=0.181)相关。②株高、穗颈长、穗下节长等耐冷性状在亲本强弱耐冷系统群间的差异明显,表现为亲本耐冷性强的材料秆和穗较长、穗粒数较多,同一性状变异程度减小。但随着回交代数的增加,这些性状的平均值逐渐趋同于轮回亲本,差异减小。③穗颈长、穗下节长、每穗实粒数、每穗秕粒数与结实率在5个稻作区间的变化规律呈现一致性,亲本和F5的差异较大,而BC1F4、BC2F3和BC3F2的差异较小,且趋同于轮回亲本。通过连续回交,在BC3F1即可获得耐冷性状表现良好的材料。

Under natural low temperature （17.8 ℃, Cold damage）in Kunming, cold tolerance at booting stage of the parents and hybrids were analyzed by using 236 accessions Japanica with core collection for rice landrace in Yunnan and Hexi 35 （Oryza satica ）, and their F5, BC1F4, BC2F3 and BC3F2 generation. The result showed that： ① Correlation among cold tolerance traits of donor parents at booting stage was high their hybriding generations. The correlation of cold tolerance for backcross hybrids decreased in accompany with the addition of backcross, and it was accessible to backcross parent. Among the parents and hybrids was higher significant correlation coefficients（≥ 0.370） between seed setting rate and four cold tolerance index traits including peduncle length, node length under panicle, filled grain number per panicle, unfilled grain number per panicle.② The plant height, peduncle length, node length under panicle and so on cold tolerance traits, in the parent strong and the weak endures cold during the systematic group difference to be obvious, displays is long for the parent cold resistance strong material filled grains to be many, the identical character variation degree reduces. But along with backcross algebra＇s increase, these character＇s mean value by tends to be with in the recurrent parent, the difference reduces. ③ There was a similar changing trend among five rice ecological regions based on five cold tolerance index traits including peduncle length, node length tender panicle, filled grain number per panicle, unfilled grain number per panicle and seed setting rate. The difference of the parent and F5 are significant, but the BC1F4, BC2F3 and BC3F2 are low, and them with in the recurrent parent. Through the continual backcross, then obtains materials with good cold tolerance traits in BC3F1.