【作者】 陈稳良；

【导师】 刘惠民； 景蕊莲；

【作者基本信息】 山西大学 ， 作物遗传育种， 2009， 硕士

【摘要】 干旱是影响小麦（Triticum aestivum L.）生产的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农艺和生理性状进行遗传剖析和QTL定位,对小麦抗旱性的遗传改良具有重要的理论和现实意义。本研究以旱地品种晋麦47为轮回亲本、水地品种鲁麦14为供体亲本构建的BC₃F₄回交导入系（ILs）为材料,通过分子标记检测,对雨养（DS）和灌溉（WW）条件下小麦抗旱相关重要农艺性状（株高、穗下节长、旗叶叶枕-穗基部长、每穗总小穗数、穗顶部不孕小穗数、穗基部不孕小穗数、相对穗下节长、相对旗叶叶枕-穗基部长、单株穗数和千粒重）和生理性状（叶绿素含量、冠气温差和叶绿素荧光动力学参数）进行QTL定位,揭示了这些复杂数量性状的遗传基础和QTL表达规律。具体研究结果如下:1.利用512对小麦SSR标记引物对导入系的双亲晋麦47和鲁麦14进行多态性分析,共检测到147对多态性标记,占有效扩增的28.7%;利用其对供试的150个BC₃F₄株系基因型进行遗传选择,检测到2个株系分别有14个和32个标记位点的带型不同于双亲,表明这2个株系为假杂株,随后的分析材料为148个株系。基因型检测结果表明,晋麦47遗传背景的回复率达92.8%,接近其理论值93.8%。147个标记中有16个标记属于多染色体位点标记,不能确定其所属的染色体,不做进一步分析。2.根据国际小麦SSR标记整合图,将131个标记整合为回交导入系的连锁图上,并计算导入片段的数目、大小和占基因组的比例。在所有导入系中都检测到供体片段,其中,有80个标记至少出现在1个导入系中,占多态性标记的61.1%。148个导入系含有2～12个供体片段,其中2个导入系含有2个导入片段,其它均含有4个或4个以上导入片段,每个导入系平均7.5个导入片段。导入片段的长度在3.0cM～78.0cM之间,平均长度为23.6cM。导入系中的供体基因组覆盖率在1.7%～12.5%之间,平均为6.9%,导入的供体基因组总长度为1384cM,占供体基因组的54.0%。在导入系的21个染色体连锁群中,1B和6B染色体上没有检测到导入片段;5A和5D上检测到的导入片段数最多,分别为160和134。不同染色体上供体染色体的覆盖率为0～94.7%,平均覆盖率为50.9%。根据小麦SSR整合图,绘出了每条染色体的导入片段覆盖图。3.对148个导入系株系7个重要农艺性状的分析表明,在雨养和灌溉两种水分条件下,ILs群体多数性状表现超双亲,性状变异系数在2.34%～127.11%之间,性状均值偏向轮回亲本晋麦47:ILs群体在WW条件下的TNS极显著大于DS的,与鲁麦14相似,这可能是供体亲本鲁麦14基因导入的结果。除SST外,其余性状在两种水分条件下均呈极显著正相关(r=0.221^**～0.555^**)。4.利用148个导入系对抗旱相关性状进行QTL分析,通过单因素方差分析共检测到146个抗旱相关性状的QTL位点。其中株高QTL 20个,穗下节长、旗叶叶枕-穗基部长、相对穗下节长、相对旗叶叶枕-穗基部长QTL 25、23、9和15个,每穗总小穗数、穗顶部不孕小穗数、穗基部不孕小穗数及单株穗数QTL 7、12、1和3个,千粒重QTL 13个,叶绿素含量QTL 7个,冠气温差QTL 2个,叶绿素荧光动力学参数初始荧光、最大荧光、可变荧光与PSⅡ最大光化学效率QTL 4、1、1和3个。60.3%位点的正向等位变异来自供体亲本鲁麦14,39.7%位点的正向等位变异来自轮回亲本晋麦47,有些QTL位点在两种水分条件下都被检测到,可能是一些较稳定的QTL位点。分析结果为进行QTL位点的精细作图奠定了良好的基础。5.控制小麦抗旱相关重要生理和农艺性状的QTL在不同染色体间和同一染色体内的不同区段上呈现出显著的不均匀分布,在染色体一些区段上形成了QTL热点区域。检测到的28个抗旱相关QTL热点区域分布在14条染色体连锁群上。这些热点QTL区域对于深入研究抗旱性状的遗传基础具有重要意义。更多还原

【Abstract】 Drought stress is a major environment constraint greatly impacting wheat（Triticum aestivum L.） production in many 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 agronomic traits involved in the drought tolerance in wheat.A set of introgression lines（ILs） generated from repeated backcross [（Jinmai 47×Lumai 14）×Jinmai 47]BC₃F₄ was used as the plant materials in this study.The SSR markers showing polymorphism between two parents were employed to screening ILs genotype.Important traits associated with drought tolerance including agronomic traits（plant height（PH）,first internode length（FIL）,length from flag leaf pulvinus to spike base（LPSB）, total number of spikelet per spike（TNS）,sterile spikelet number at spike top （SST）,sterile spikelet number at spike bottom（SSB）,relative first internode length（RFIL）,relative length from flag leaf pulvinus to spike base（RLPSB）, spike number per plant（SNP）,thousand-grain weight（TGW））,and physiological traits（chlorophyll content（ChlC）,canopy-air temperature difference（CTD） and parameters of chlorophyll fluorescence kinetics （PCFK）） were investigated under two water regimes,drought stress（DS） and well-watered（WW）.QTLs for target traits were mapped to dissect their genetic mechanism and reveal the hot chromosome region shared by multi-QTLs.The results are as following:（1） Total of 147 markers selected from 512 SSR markers showing polymorphism between two parents Jinmai 47 and Lumai 14 were employed to screening ILs genotype,about 28.7%of the used primer pairs.The results showed that 2 of 150 ILs were detected 14 and 32 markers loci different from their parents,respectively.The genetic background of Jinmai 47 maintained 92.8%in 148 ILs access to its theory value 93.8%.Among 147 markers,16 were detected multi-locus and could not be exactly mapped to genetic lingkage map,did not be sequentially analyzed.（2） According to the wheat consensus SSR map,131 markers unique-locu were mapped in the linkage map.Total of 148 ILs were selected to detect the number,size of introgressed segment,and their ratio accounted for the whole donor genome were estimated.Eighty markers appeared in at least one introgressed line,account for 61.1%of the polymorphic markers. Two of 148 ILs detected two and the others contained 4 or more than 4 introgression fragments.Two to twelve donor fragments were identified in the 148 lines,average of 7.5 in each introgression line.The length of the introgression fragment ranged from 3 cM to 78 cM,the average length 23.6 cM.The donor genome of Lumai 14 was represented between 1.7%and 12.5%in the ILs with an average of 6.9%.The total length of the introgressed Lumai 14 genome was 1384 cM,covering 54.0%of the donor genome. Among the 21 linkage groups,there is no introgressed donor fragment in 1B and 6B chromosome,but 5A and 5D detected the most,160 and 134 introgression fragments,respectively.The introgressed donor chromosome covered from 0 to 94.7%of 21 chromsomes,and average of 50.9%.Based on the wheat SSR consensus map,the coverage map of the introgressed segments for each of the chromosomes was drawn.（3） The ILs phenotypes of seven important agronomy traits were analysised.Most traits of ILs exhibited transgressive segregation. Coefficients of variation for all traits in ILs ranged from 2.34%to 127.11% under two water regimes.The averages of all traits in ILs presented the tendency to be more adjacent to the recurrent parent Jinmai 47.It is similar to donor parent Lumai 14 that ILs TNS under rainfed condition were higher than that under well-watered,which maybe due to the introgression of favorable alleles from the exotic donor.All correlation coefficients for ILs traits were significant(r=0.221^**～0.555^**) between the rained and the well-watered conditions except SST.（4） QTL analysis was performed in the 148 ILs.Total of 146 QTLs,20 for PH,25 for FIL,23 for LPSB,7 for TNS,12 for SST,1 for SSB,9 for RFIL,15 for RLPSB,3 for SNP,13 for TGW,7 for CHlC,2 for CTD and 9 for PCFK（Fo,Fm,Fv andφPo）,were detected by one way ANOVA analysis. Among the 146 QTLs,60.3%of positive alleles were from the donor parent Lumai 14,39.7%from the recurrent parent Jinmai 47.Part of the QTLs was detected under two water regimes which indicated they expressed stably. Above results made the foundation for fine mapping and cloning of the target QTLs.（5） 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.Total of 28 hot-spot regions for target traits distributed on 14 chromosomes.They were crucial regions for further elucidating genetic basis of drought-tolerant traits.更多还原