【作者】 钱雪娅；

【导师】 王辉；

【作者基本信息】 西北农林科技大学 ， 作物遗传育种， 2009， 博士

【摘要】 干旱是影响小麦(Triticum aestivum L.)生产的最主要的非生物胁迫因素,小麦对非生物逆境的抗性或耐性是多基因控制的数量性状,易受环境条件的影响。分子数量遗传学的发展为深入研究数量性状的遗传基础提供了可能,开展小麦抗旱相关复杂数量性状的QTL定位和遗传剖析,增强对这些性状遗传基础的认识,对于提高抗旱育种效率具有重要的意义。本研究在干旱胁迫和正常灌溉两种水分条件下,利用小麦抗旱性强的旱地品种旱选10号与水地高产品种鲁麦14杂交创建的加倍单倍体群体(doubled haploid lines,DHLs)(共150个株系)为遗传研究材料,(1)考察不同年份和地点田间小麦重要形态性状(灌浆期上部3叶长、宽以及叶基角、穗下节长、株高)、生理性状(叶片持绿性和离体叶片失水速率)、生育期(抽穗期和扬花期)和产量相关性状(穗长、小穗数、不孕小穗数、穗粒数、穗粒重、籽粒长、籽粒宽以及千粒重);(2)考察不同播种深度(3 cm、6 cm和9 cm播深)、PEG(polyethylene glycol)处理和对照条件下的胚芽长、胚芽鞘重、幼苗株高,以及干旱胁迫和正常灌溉条件下的幼苗生物学产量。对这些性状进行QTL定位、效应分析以及相关QTL位点与环境的互作效应分析,探讨环境条件对目标性状的影响以及性状间的相互关系。主要研究结果如下:1、随着播种深度的增加,小麦胚芽鞘长、重及幼苗株高增加;对照条件下的幼苗株高明显高于PEG胁迫处理的,而对照条件下的胚芽鞘长、重的表型值低于PEG处理的;干旱胁迫抑制小麦的生长发育,导致植株幼苗生物量减少、叶片大小变小、植株变矮,加速植株衰老,进而导致减产。2、小麦重要形态、生理、生育期和产量相关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。控制这些性状的遗传因子不仅有加性、上位性,一些性状还检测到加性×环境(A-QEI)和上位性×环境(E-QEI)的显著互作。3、控制目标性状的QTL位点在不同染色体上或同一染色体内的不同区间上呈现出显著的不均匀分布,在染色体一些区间上形成了QTL热点区域;另外一些稳定表达的QTL位点在不同年份被重复检测到。4、共检测到13个和24对控制胚芽鞘长、胚芽鞘重、幼苗株高以及幼苗生物量的加性和上位性QTL,分布在除1A、1D和6D以外的18条染色体上;在4D的Xgwm165.2～Xgwm192区间内检测到控制胚芽鞘长、胚芽鞘重以及幼苗株高的重合位点;在6A(P3465-460～P3526-130)和7B(Xpsp3033～Xgwm297)分别同时检测到幼苗株高、幼苗生物量和胚芽鞘长、胚芽鞘重的加性QTL位点;7个加性QTL和11对上位性QTL与环境发生显著互作。5、检测到50个加性QTL和22对上位性QTL控制灌浆期顶部3叶长、宽及叶基角,分布在除6D以外的20条染色体上;2B染色体的Xgwm630～WMC223、2D的WMC453.1～WMC18、3B的P3156-1851～P5138-100、5A的Xgwm304～P2470-280、Xgwm595～WMC410、WMC410～WMC74和Xgwm291～Xgwm410,以及7B的Xpsp3033～Xgwm297,是多个QTL共享的标记区间。QTL位点QFll.cgb-5A-1、QSll.cgb-5A-1、QTll.cgb-5A-1、QFlw.cgb-2B、QFlw.cgb-3B-2、QSlw.cgb-3B、QFla.cgb-1B、QFla.cgb-5A-1、QSla.cgb-5A-1和QTla.cgb-3B在两年中均被重复检测到;1个控制倒2叶基角的加性QTL位点和1对控制倒2叶长的上位性QTL与干旱胁迫环境发生显著互作。6、控制叶绿素含量和离体叶片失水速率的QTL位点分布在除1A、3D、4D和6D的17条染色体上;在5A染色体的标记区间P2470-280～Xgwm154内,检测到控制不同发育时期叶绿素含量的QTL位点(QChlc.cgb-5A-3),在7D染色体WMC436～Xgwm44区间内同时检测到控制抽穗期离体叶片在不同处理时间失水速率的QTL位点;3个加性QTL及3对上位性QTL与环境发生显著互作。7、共检测到14个控制抽穗期和扬花期的加性QTL和5对上位性QTL,分布在1B、1D、2D、3A、3B、4D、5A、6B、7A、7B和7D染色体上;Q.Hs.cgb-1D、Q.Fd.cgb-1D-1和Q.Hs.cgb-3A、Q.Fd.cgb-3A分别同时定位在1D的WMC432～WMC222和3A的Xgwm391～P8422-170区间内;Q.Hs.cgb-7B-2和Q.Fd.cgb-1B-1与水分环境具有显著互作。8、分别检测到10个产量相关性状的62个加性和29对上位性QTL,涉及小麦18条染色体(除1D、5D和6D外),主要分布在1B、2D、3B、6A和7A染色体上(≥10)。在染色体1B、2B、2D、3B、3D、4A、4D、5B、6A和7A上检测到多个性状QTL共享的标记区间;Q.Sn.cgb-1B-3、Q.Ils.cgb-2D-1、Q.Ph.cgb-2D、Q.Sl.cgb-2D-1、Q.Isn.cgb-5A-1、Q.Sn.cgb-6A和Q.Sl.cgb-7B在两年中均被检测到。本研究首次在不同处理条件下对小麦顶部3叶长、宽以及叶基角、胚芽鞘长、胚芽鞘重、幼苗株高、粒长和粒宽进行了QTL定位分析,同时也在不同水分条件下对小麦重要的生理以及产量相关性状进行QTL定位和遗传剖析,揭示了这些复杂数量性状的遗传基础和QTL表达规律,为发掘小麦重要形态、生理以及产量相关性状的分子标记,进行标记辅助选择育种及抗旱性的遗传改良提供了理论依据和技术支撑。稳定表达的加性QTL位点和QTL热点区域对于进行QTL的功能研究及图位克隆具有重要意义。更多还原

【Abstract】 Drought stress is a major environment constraint greatly impacting wheat (Triticum aestivum L.) production in many wheat planted area that rely on rainfed of the world. The resistance or tolerance to abiotic stress were essentially subjected to complex quantitative genetics regulated by minor-effect polygenes, which were easily affected by different environments. The development of molecular quantitative genetics for studying the genetic basis of quantitative traits provides the possibility. Therefore, it is very important to improve the efficiency of drought resistance breeding plays an important role that to map QTLs and to dissect genetic factors for complex quantitative traits, and to enhance awareness of these traits.Doubled haploid lines (DHLs) (Hanxuan 10×Lumai 14) (150 lines) were selected as experiment materials in this study, (1) Under rainfed (drought stress) and well-watered conditions, important agronomic traits including morphological traits (leaf length, leaf width, leaf angle of the top three leaves, first internode length below spike (ILS) and plant height (PH) ), physiological traits (chlorophyll content, ChlC and rate of excised-leaf water loss,RWL), growth period (heading date (HD) and flowering date (FD) and yield-related traits (spike length (SL), spikelet number (SN), infertile spikelet number (ISN), grain number per spike (GNS), grain weight per spike (GWS), grain length (GL), grain width (GW) and thousand grain weight (TGW)) were investigated in two years; (2) coleoptile length (CL), coleoptile weight (CW), seedling height (SH) under different sowing depth, PEG (polyethylene glycol) treatment and water control conditions and seedling biomass (SB) (under drought stress and well-watered) simultaneously investigaed. QTL (quantitative trait loci) mapping and QTLs×water environment interactions (QEIs) were analyzed for these target traits, and explored environmental conditions that had impacted on these target traits, as well as relatonship between target traits. Main research results were as follows:1. Coleoptile length, weight and seedling height increased with the increase of sowing depth. Plant height of control was significantly higher than PEG treatment, but coleoptile length and weight were converse. Drought stress inhibited the seedling growth, resulting in the reduced of seedling biomass, leaf size and plant height, accelerated plant senescence, which eventually led to the reduction of production.2. Many important morphological, physiological and agronomic traits of wheat showed significantly sensitive to drought stress, which were characters of complex quantitative traits and easily affected by different environments. The genetic factors regulating these traits consisted of additive QTLs, epistatic QTLs, additive QEIs (A-QEIs) and epistatic QEIs (E-QEIs) effects.3. Major and minor QTLs for all target traits showed disequilibrium distribution among different chromosomes and even different intervals in the same chromosome. These QTLs assembled in some specific interval formed the hot-spot region for regulating inheritances of corresponding traits; some stable expression QTLs were detected in different years.4. A total of 13 additive and 24 pairs of epistatic QTLs were detected for CL, CW, SH and SB, which distributed on 18 (except for 1A, 1D and 6D) chromosomes. Co-located QTLs for CL, CW and SH were detected in the interval Xgwm165.2～Xgwm192 on 4D; major QTL loci for SH, SB and CL, CW were found in P3465-460～P3526-130 on 6A and Xpsp3033～Xgwm297 on 7B, respectively; 7 additive QTL and 10 pairs of epistatic QTL were identified significant QEIs with environment.5. A total of 50 additive and 22 epistatic QTLs were detected for leaf length, leaf width, and leaf angle of the top three leaves, which distributed on 20 (except for 6D) chromosomes. Xgwm630～WMC223 on 2B, WMC453.1～WMC18 on 2D, P3156-1851～P5138-100 on 3B, Xgwm304～P2470-280, Xgwm595～WMC410, WMC410～WMC74 and Xgwm291～Xgwm410 on 5A and Xpsp3033～Xgwm297 on 7B were common regions shared by multi-trait QTLs. QFll.cgb-5A-1, QSll.cgb-5A-1, QTll.cgb-5A-1, QFlw.cgb-2B, QFlw.cgb-3B-2, QSlw.cgb-3B, QFla.cgb-1B, QFla.cgb-5A-1, QSla.cgb-5A-1 and QTla.cgb-3B were detected in both two years. One additive QTL for second leaf angle and one pair of epistatic QTL for second leaf length were found significant QEIs with rainfed environment.6. QTLs for ChlC and RWL were distributed on 17 (except for 1A, 3D, 4D and 6D) chromosomes; QTL for ChlC in different development stages were detected in the interval P2470-280～Xgwm on 5A, QTL for different excised duration in heading date were detected in WMC436～Xgwm44 on 7D. Total of 3 additive QTL and 3 pairs of epistatic QTL were found significant QEIs with water environment.7. A total of 14 additive and 5 pairs of epistatic QTLs were detected for HD and FD which distributed on 1B, 1D, 2D, 3A, 3B, 4D, 6B, 7A, 7B and 7D chromosomes. Q.Hd.cgb-1D, Q.Fd.cgb-1D-1 and Q.Hd.cgb-3A, Q.Fd.cgb-3A were simultaneously located on the interval WMC432～WMC222 on 1D and Xgwm391～P8422-170 on 3A; QHd.cgb-7B-2 and Q.Fd.cgb-1B-1 were found significant A-QEIs with rainfed environment.8. A total of 62 additive and 29 pairs of epistatic QTLs for 10 yield relative traits in DHLs were distributed on 18 chromosomes (except for 1D, 5D and 6D), of which more QTLs were distributed on 1B, 2D, 3B, 6A and 7A(≥10). Some intervals were common shared by multi-trait QTLs on 1B, 2B, 2D, 3B, 3D, 4A, 4D, 5B, 6A and 7A chromosomes; Q.Sn.cgb-1B-3, Q.Ils.cgb-2D-1, Q.Ph.cgb-2D, Q.Sl.cgb-2D-1, Q.Isn.cgb-5A-1, Q.Sn.cgb-6A and Q.Sl.cgb-7B were simultaneously in different years; 4 additive QTLs and 1 pair of epistatic QTL were found significant QEIs with water environment.In present study, QTL analysis for leaf length, width and leaf angle of the top three leaves, CL, CW, SH, GL and GW were dissected for the first time at different treatment, and QTL mapping and genetic basis were also dissected for the traits associated with important physiology and yield under different water regimes. The results rvealed the genetic basis of the complex quantitative traits related to drought stress tolerance, provided a genetic basis and techniques for marker-assisted selection and genetic improvement of drought tolerance. And, some important QTLs with stable expression and some important hot-spot chromosome regions for specific traits played critical roles to QTL functional research and clone based on mapping.更多还原