小麦叶面积指数的遗传变异及其影响因素与产量的关系

以"小偃54×京411"的96个重组自交系(RILs)为试材,分析小麦叶面积指数(LAI)相关性状的遗传变异及其影响因素。结果表明,不同生育时期的LAI、MTA(平均叶倾角)、DIFN(无截取散射)均在RIL间存在极显著差异。LAI在RIL群体中呈连续的正态分布。LAI自抽穗期增大,至开花期达最大,灌浆后期降低。不同生育时期的LAI均与群体总茎数、株高和倒三叶叶长呈极显著正相关。灌浆后期的LAI与生物量和产量呈极显著正相关。当控制总茎数和株高不变时,LAI主要与顶三叶的叶面积和叶长呈正相关,其相关系数在开花期最大,灌浆后期降低。对抽穗期LAI>4.0的RIL系而言,该时期LAI与生物量和产量相关性不显著,但灌浆后期的群体平均叶倾角与生物量和产量呈显著正相关。对产量高于京411且株高小于80cm的8个RIL系的分析表明,旗叶与倒二叶叶长比与生物量和产量呈正相关。

The Genetic Variation of LAI and the Relationship between Its Influence Factors and Yield in Wheat(Triticum aestivum)

The genetic variation of LAI(Leaf area index) related traits and their influence on biomass and yield were evaluated on 96 recombinant inbred lines(RILs) together with their parents Xiaoyan 54(XY54) and Jing 411(J411).LAI,MTA(mean tilt angle) and DIFN(diffuse non-interceptance) showed significant difference among RILs at the heading,flowering,and late grain filling stages,respectively.LAI reached its highest values at the flowering stage,and then decreased at the late grain filling stage.LAI was significantly and positively related with total stems,plant height,and the length of third leaf at each stage.When controlling total stems and plant height,LAI was positively related with leaf areas and the lengths of flag,second,and third leaves at the heading and flowering stages;it was also related with biomass,but not with grain yield at the late grain filling stage.When LAI at heading stage was higher than 4.0,no significant correlation was observed between LAI and biomass or grain yield,but MTA at the late grain filling stage showed significant correlation with biomass and grain yield.For the 23 high-yielding RILs which showed better yield performance than J411,the control variety in northern China winter wheat region,biomass and yield were positively correlated with plant height.Considering the lodging risk from higher plant height,we analyzed the eight high-yielding RILs with plant height lower than 80 cm.We found,interestingly,that biomass and grain yield were significantly and positively correlated with the ratio of the lengths between flag leaf and second leaf.LAI showed large genetic variation and exhibited continuously normal distribution in the RIL population.Therefore,LAI was determined mostly by total stems,plant height,and third leaf length as well as by the areas and lengths of the top three leaves when controlling total stems and plant height.For RILs with higher LAI than 4.0,larger MTA at the late grain filling stage means higher biomass and grain yield.Higher ratio of the lengths between flag and second leaf may be a candidate selection index for high-yielding dwarf or semi-dwarf varieties.