【作者】 武仙山；

【导师】 景蕊莲；

【作者基本信息】 中国农业科学院 ， 生物化学与分子生物学， 2008， 博士

【摘要】 干旱是影响小麦(Triticum aestivum L.)生产的最主要非生物胁迫因素。作物抗旱性是复杂的数量性状,对小麦抗旱相关重要生理和农艺性状进行QTL遗传剖析,对小麦抗旱性的遗传改良具有重要理论和现实意义。本研究以DH群体(旱选10号×鲁麦14)和RIL群体(Opata 85×W7984)为材料,在不同年点水分组合环境、不同发育时期调查抗旱相关生理性状(叶绿素含量(ChlC)和叶绿素荧光动力学参数(PCFK))及农艺性状(株高、单株分蘖数、单株穗数、单株结实穗数、分蘖成穗率、结实穗率、单株粒重、生物学产量、收获指数和千粒重),运用条件分析等方法估算代表各性状对干旱胁迫环境特异反应和抗旱性的旱胁迫系数(DS|WW)和抗旱指数(DRI)。并通过非条件和条件QTL遗传分析方法,揭示这些性状发育的遗传控制基础和重要抗旱相关QTL区域。主要研究结果如下:1.小麦抗旱相关生理性状和农艺性状对干旱胁迫反应敏感,属微效多基因控制的复杂数量性状。控制这些性状的QTL表现加性效应和上位性效应。许多QTL通过与其它QTL发生上位互作形成QTL遗传网络,QTL与环境的互作效应是抗旱相关性状遗传基础的重要组成部分,小麦分子标记辅助选择育种应考虑QTL位点间的复杂制约关系,兼顾广适性QTL和环境特异性QTL的选用。2.控制株高发育的基因在DH群体比在RIL群体发生了更广泛分离,涉及除6D外的所有染色体。同时表达加性和上位性效应的QTL参与QTL网络是DH群体株高的主要遗传控制形式。加性主效效应主要在拔节前表达,是株高遗传变异的主要来源。株高发育旱胁迫系数(DS|WW)主要源于环境互作效应。株高发育抗旱指数(DRI)的主要遗传成分是加性主效效应,主要在早期表达。3. DH群体ChlC在不同时期受加性主效效应或上位主效效应控制,环境对ChlC的影响较小;上位效应是控制DH群体PCFK及其衍生性状的主要遗传效应,但多数PCFK参数QTL表达也受环境的显著影响。4.同时表达加性和上位性效应的QTL与其它QTL形成的QTL遗传网络是控制千粒重的主要遗传基础,加性主效效应是千粒重的主要遗传效应。控制单株分蘖数、单株穗数、单株结实穗数、分蘖成穗率、结实穗率、生物学产量、单株粒重和收获指数的主要遗传成分依次是加性、上位性、上位性、加性、加性、加性、上位性和加性效应,环境对各性状的表现均有影响。5.染色体1B的WMC156～P3446.1、2D的3个区域WMC181～P3470.3、WMC453.1～WMC18～Xgwm30及Xgwm157～Xgwm539、3A的CWM48.1～WMC532、4D的Xgwm165.2～Xgwm192、5A的WMC410～WMC74～Xgwm291～Xgwm410、6A的Xpsp3071～Xgwm570等是多个性状QTL共享的标记区间,对进一步研究抗旱性状的遗传基础具有重要意义。本文对小麦抗旱相关重要生理和农艺性状及其发育动态进行了分子水平的遗传剖析,为通过分子育种进行小麦抗旱性的遗传改良提供了理论依据和技术支撑。更多还原

【Abstract】 Drought stress is a major environment constraint greatly impacting wheat (Triticum aestivum L.) production in many arid and semi-arid areas of the world. Drought tolerance is a complex quantitative trait; it is very essential for genetic improvement of drought tolerance to dissect quantitative loci for physiological and morphological traits involved in the drought tolerance in wheat.Doubled haploid lines (DHLs) (Hanxuan 10×Lumai 14) and recombinant inbred lines (RILs) (Opata85×W7984) were selected as experiment materials in this study. Important traits associated with drought tolerance including physiological traits (chlorophyll content (ChlC) and parameters of chlorophyll fluorescence kinetics (PCFK)) and agronomic traits (plant height, number of tiller per plant (NT), spike number per plant (SNP), number of setting spike per plant (NSSP), ratio of setting spike number to maximal tiller number (RSST), ratio of setting spike number to total spike number (RSSS), biomass yield (BY), grain yield per plant (GYP), harvest index (HI) and weight of thousand grain (WTG)) were investigated in different locations and years under two water regimes, drought stress (DS) and well-watered condition (WW). Drought stress coefficient (DS|WW) and drought resistance index (DRI) were estimated for the given traits through conditional analysis to evaluate their special reaction under DS and to assess drought tolerance of them, respectively. QTL for target traits and their derived traits (DS|WW and DRI) were mapped to dissect their genetic mechanism and reveal the hot chromosome region shared by multi-QTLs. The major results were as follows:1. All target traits of DHLs and RILs showed significantly sensitive to drought stress, which was the character of complex quantitative traits. These traits were controlled by QTLs with additive effect and/or epistatic effect. Some QTLs were involved in complex QTL network, and some responded to specific environment, therefore, marker-assisted selection (MAS) for drought tolerance should give attention to both kinds of QTLs.2. Genes of plant height were detected on all chromosomes except 6D. It is deduced that genes of plant height segregate widerly in DHLs than in RILs. QTLs with additive and epistatic effects were the important genetic component for plant height, most of which acted in QTL networks. And additive main effect (A) was the major genetic effect for plant height, which expressed greatly in S1|S0. DS|WW of plant height on ontogeny was mainly affected by environment components. The major genetic component for DRI of plant height was additive main effect, which mainly expressed in S1|S0.3. ChlC in DHLs was mainly controlled by A effect or AA effect in different stages, which were hardly affected by environments. Epistatic effect was the major genetic effect for most PCFK and their derived traits; environments greatly affected these PCFK-related traits.4. QTLs with the additive and epistatic effects being involved in QTL genetic networks were the major genetic basis for WTG, and additive genetic main effect was its main genetic effect. The major genetic effects for NT, SNP, NSSP, RSST, RSSS, BY, GYP and HI were additive, epistatic, epistatic, additive, additive, additive, epistatic and additive effects in turn, which showed sensitive to environments.5. WMC156～P3446.1 on 1B, WMC181～P3470.3, WMC453.1～WMC18～Xgwm30 and Xgwm157～Xgwm539 on 2D, CWM48.1～WMC532 on 3A, Xgwm165.2～Xgwm192 on 4D, WMC410～WMC74～Xgwm291～Xgwm410 on 5A, and Xpsp3071～Xgwm570 on 6A were common regions shared by multi-traits. They were crucial regions for further elucidating genetic basis of drought-tolerant traits.In conclusion, the present research dissected genetically physiological and morphological traits associated significantly with drought tolerance on ontogeny in wheat. The results provided a genetic basis and techniques for improving drought tolerance by molecular breeding in wheat.更多还原