摘要：
以小麦回交导入系(ILs)群体(西峰20×晋麦47)160个株系及其亲本作为供试材料,研究干旱胁迫(DS)和正常灌溉(WW)条件下小麦不同发育时期旗叶叶绿素含量(ChlC)和千粒重(TGW)遗传特点和相互关系,并且评价该群体的遗传变异.结果表明,在两种水分条件下,小麦ILs群体及亲本的不同发育阶段旗叶ChlC和TGW表型值均呈显著差异,WW条件下的各性状表型值显著高于DS条件下的,旱胁迫系数在0.79~0.91之间.在两种水分条件下,小麦ILs群体各性状表型值介于双亲之间,且偏向于轮回亲本晋麦47,体现出回交导入系群体的遗传特性.群体内各性状表型变异广泛,且存在超亲分离,变异系数在8.39% ~16.71%(DS)和8.61% ~16.54%(WW),多样性指数在0.74~0.83(DS)和0.71~0.82(WW),遗传力较低,在0.29~0.62(DS)和0.20~0.50(WW)之间.ChlC与TGW间呈现极显著正相关(r=0.500* *~0.629* *,DS;0.488* *~0.622* *,WW),其中灌浆期的旗叶ChlC与TGW表现出较高的相关性(r=0.629* *,DS;0.622* *,WW),DS条件下的相关系数普遍高于WW的;同时ChlC对TGW具有显著的正向直接作用,灌浆期ChlC正向直接作用较大(0.582* *,DS;0.312* *,WW).说明该群体适合进行小麦抗旱性状数量遗传研究,其研究结果将为进一步解析干旱调控小麦持绿性和千粒重表型变异的遗传基础,及其QTL精细定位奠定一定的理论基础.%A total of 160 introgression lines(ILs)and two parents,Xifeng 20 and Jinmai 47,were used to investi-gate quantitative genetic characteristics of chlorophyll content(ChlC)of flag leaf at different development stages and thousand-grain weight(TGW),and evaluate the correlations between the two traits and genetic variations of the ILs under drought stress(DS)and well-watered(WW)conditions.The results showed that there were significant differences in phenotypic values of ChlC at different growth stages and TGW in wheat ILs and two parents under two water conditions. All phenotypic values under the WW condition were significantly higher than those under the DS,associated with the drought-stress coefficients ranging from 0.79 to 0.91.Under two water conditions,the phenotypic means of all traits in the ILs were intermediated between those of two parents,but tended to be closer to the recurrent parent Jingmai 47.Thephenotypic values of all traits in the ILs varied widely,altogether with presenting substantial transgressive segrega-tion.The coefficients of variations differed from 8.39% to 16.71% under the DS and from 8.61% to 16.54% under the WW,while the genetic diversity indices altered from 0.74 to 0.83 under the DS and from 0.71 to 0.82 under the WW.The heritability of all traits was lower,with a range of 0.29 to 0.62 under the DS and 0.20 to 0.50 under the WW.There were significantly positive correlations(r=0.500* *~0.629* *,DS;0.488* *~0.622* *,WW)be-tween ChlC and TGW,with ChlC having higher correlation coefficients at the grain-filling stage and under the DS condi-tion.Furthermore,ChlC showed positive effects on TGW,and higher effects(0.582* *,DS;0.312* *,WW)to TGW were associated with ChlC at the grain-filling stage.The result indicates the feasibility of using the ILs in quantitative ge-netic study in wheat drought tolerance,providing a theoretical basis for further dissecting the genetic basis and QTL fine mapping for green-stay trait and thousand-grain weight in wheat regulated by drought stress.
