【作者】 王芳；

【导师】 盖钧镒；

【作者基本信息】 南京农业大学 ， 作物遗传育种， 2007， 博士

【摘要】 涝害是世界上许多国家的重大自然灾害。大豆原产于我国,从南到北,包括江汉平原以及长江中下游平原有着广泛栽培。这两个地区处在亚热带季风气候控制下,在5～9月常有暴雨甚至大暴雨发生,这一时期正是大豆的生长时期,常使大豆发生涝害,严重影响大豆的生产。因此,选育能够在湿涝土壤上生长的耐性大豆品种具有重要的实践意义。耐涝性分为耐湿/渍性和耐淹性。本研究旨在建立大豆耐淹性的鉴定方法,对丰富的大豆种质资源进行耐淹性鉴定,研究我国各生态区大豆种质资源耐淹性的变异特点,发掘优异资源;同时研究不同耐淹性大豆的形态解剖变化,耐淹性的遗传机制,定位耐淹性QTL,筛选与之紧密连锁的分子标记以期为耐涝育种的标记辅助选择提供参考。1.耐涝性指标筛选结果,涝、渍处理下以根、茎生长为指标的环境波动大、时间长,而全淹条件下死苗率鉴定方法相对最稳定、最简单。2005和2006年,在南京农业大学江浦试验站的简易温室内,以相对死苗率为鉴定指标,对来源地不同的749份大豆资源,其中栽培大豆[Glycine max(L.)Merr.]545份,野生大豆[Glycine soja Seib.etZucc.]204份,分4批进行苗期耐淹性盆栽鉴定试验,通过共同对照进行比较分析。结果表明:(1)野生和栽培大豆耐淹性均存在相当大的遗传变异,野生和栽培大豆相对死苗率变幅分别为0.0%～207.4%、0.0%～222.2%,呈现出中间多、两头少的单峰态分布;野生大豆中的极端耐淹材料略比栽培大豆的多,但在全国二者大部分材料的耐淹性差异不大;野生大豆的耐淹性在生态区域内和生态区域间均存在一定的变异,栽培种的耐淹性在生态区域内的变异比生态区域间的变异大,各个生态区域内均存在丰富的变异,变异系数均在30.0%以上。(2)耐淹性与地理纬度、籽粒大小、生育期长短及脂肪含量等有低程度相关。(3)遴选出N24835.0、N24850.0、N23444.0、N04974.1等11份高度耐淹的野生和栽培优异种质,相对死苗率均为0.0%,占所选资源总数的1.5%。这些特异材料分别来自Ⅰ、Ⅱ、Ⅲ、Ⅳ、Ⅵ生态区,可供耐淹性新品种选育和有关形态解剖、生理生化、遗传等耐淹基础性研究。2.以不耐淹的南农1138-2和高耐淹的科丰1号、PI342618B、PI326582B为试验材料(前两者为栽培大豆;后两者为野生大豆),在盆栽条件下人工模拟水涝胁迫,调查其形态性状和解剖结构。结果显示:(1)涝胁迫对大豆地下部的负面影响比对地上部大,表现在地下部主根长变短,侧根稀疏,地上部新生叶片小,植株下部叶片黄化,株高增量和茎干重反而高于对照。(2)主根长、侧根数、根干重、根冠比各性状的相对受害率(relative iniury rate,RIR)从大到小顺序均为南农1138-2、科丰1号、PI326582B、PI342618B,与材料的耐淹性强弱正好相反。(3)涝处理后,大豆淹水茎基部逐渐增粗并产生不定根,供试栽培大豆不定根和主根的皮层均形成通气组织且耐淹性强的科丰1号比耐淹性弱的南农1138-2发达;但耐淹野生大豆体内(不定根、主根及茎叶)均未见通气组织结构,表明耐性种质除形成发达通气组织外,还存在其它耐涝机制。3.选用“科丰1号(高度耐淹)×南农1138-2(不耐淹)”衍生的184个重组自交系(NJRIKY)及其亲本为材料,以盆栽全淹条件下的存活率为耐淹性指标,进行耐淹性遗传分析和QTL定位。遗传分析采用主基因+多基因混合遗传模型分离分析法;QTL定位研究是在国家大豆改良中心提供的遗传图谱基础上,利用WinQTLCartographer Version 2.5软件的复合区间作图法(CIM)及多区间作图法(MIM)进行的。该遗传图谱共包含25个连锁群、488个标记,覆盖基因组4226.4cM,每个连锁群平均19.5个标记,标记平均间距8.6cM。结果表明:(1)两次试验的耐淹性均存在超亲变异,试验间、家系间以及试验与家系互作间的差异均极显著。(2)NJRIKY大豆群体的耐淹性为3对等加性主基因(即F-3)遗传模型,主基因遗传率为42.40%。(3)在QTL分析中,CIM和MIM共同检测到3个耐淹QTL,分别位于A1、D1a和G连锁群上的Satt648～K418 2V、Satt531～A941V和Satt038～Satt275(B53B～Satt038)区间,表型贡献率为4.4%～7.6%。分离分析与QTL定位的结果相对一致,至少有3个主基因或QTL,两者能相互印证。本研究对大豆耐淹性定位结果与前人定位结果有一定的差异,有待进一步研究的检验和拓展。更多还原

【Abstract】 Flooding is often a serious natural disaster in the world.Soybean,originated in China, is planted from the south to the north in the country,including Jiang-Han Plain and the Middle and Lower valleys of Changjiang River.In the two regions,under the control of a subtropical monsoon climate,there often happen some heavy rainstorms during May to September,which cause flooding during soybean growing stages and then cause the reduction of soybean yield.Therefore,breeding for soybeans with flooding tolerance is of great significance for enhancing productivity.Flooding tolerance has been recognized in two categories:tolerance to soil waterlogging and tolerance to submergence.The main objectives of this study were:（1） to establish identification procedure of flooding tolerance,to evaluate the variation of submergence tolerance among soybean germplasm from different eco-regions in China,and to dentify elite accessions with submergence tolerance;（2） to study the morpho-anatomical characteristics of soybeans with different submergence tolerance;（3） to reveal the inheritance mechanism and to map QTLs of submergence tolerance.A total of 749 accessions,composed of 545 accessions of cultivated soybean[Glycine max（L.）Merr.]and 204 accessions of annual wild soybean[Glycine soja Sieb.et Zucc.], sampled from different eco-regions,were used in the pot experiment in 2005 and 2006. According to the preliminary studies,tolerance to submergence with relative death percentage as tolerance index was used in the later experiments due to its better stability and simplicity in comparison with the other indices.The submergence experiment of soybean was conducted at seedling stage with artificial flooding under randomized complete blocks design in the plastic greenhouse at Jiangpu Station,Nanjing Agricultural University.（1） There showed significant genetic differences among the genotypes of both wild and cultivated soybean.A single peak frequency distribution with the majority in the middle part and less frequencies at both sides was observed,the relative death percentage （RDP） of wild and cultivated soybean varied between 0.0%and 207.4%,0.0%and 222.2%, respectively.The frequency of highly tolerant wild soybean was slightly more than that of cultivated soybean,but most part of both cultivated and wild soybean was intermediate and less sensitive to submergence.There existed certain amount of variation of submergence tolerance both within and among eco-regions in G soja,while in G max the among eco-region variation was smaller than the within eco-region variation,of which the CV values were all more than 30.0%.（2） There showed a weak correlation between submergence tolerance and some traits,including geographical latitude,100-seed weight, maturity date,and fat content.（3） Eleven elite accessions with high tolerance to submergence,including eight G soja and three G max accessions,such as N24835.0, N24850.0,N23444.0,N04974.1,et al.were identified and screened out.The relative death percentage of them was 0.0%,and they accounted for 1.5%of total accessions from Eco-regionⅠ,Ⅱ,Ⅲ,Ⅳ,andⅥ.These accessions will be important sources for future submergence tolerance breeding programs and fundamental researches on morphology, anatomy,physiology,biochemistry and genetics.The morpho-anatomical characteristics of submergence tolerance was studied in an artificial flooding experiment in pots with Nannong 1138-2（sensitive,G max）,Kefeng No.1（highly tolerant,G.max）,PI342618B（highly tolerant,G.soja）,PI326582B（highly tolerant,G.soja）.（1） Flooding stress caused more adverse effects on underground root system than on aboveground shoot system,with tap root length shorter,lateral roots sparse and total roots reduced,while new leave size reduced,lower part leaves chlorotic,plant height and dry shoot weight increased.（2） The descending order of relative injury rate（RIR） of taproot length,number of lateral roots,dry root weight and root/shoot ratio was Nannong 1138-2,Kefeng No.1,PI326582B,PI342618B,adverse to the order of submergence tolerance.（3） Under flooding,the submerged stem base was thick and hypertrophied,and adventitious roots emerged from the flooded part of the stem above the soil.Aerenchyma formation occurred in adventitious root and tap root cortex of cultivated soybeans（G.max）, and highly tolerant Kefeng No.1 had more extensive aerenchyma tissues than sensitive Nannong 1138-2 did.Wild soybeans（G.soja） expressed no aerenchyma formation in adventitious roots,tap roots,stems and leaves.Kefeng No.1（highly tolerant） and Nannong 1138-2（sensitive）,with large difference in submergence tolerance between the two parents,were used to study the inheritance of submergence tolerance in soybean.The survival percentage of seedlings of the RIL population NJRIKY derived from Kefeng No.1×Nannong 1138-2 was evaluated under completely submerged condition in pot experiment.Genetic analysis was performed under major gene plus polygene mixed inheritance model in the P₁,P₂,and F_7:11 of the cross ’Kefeng No.1×Nannong 1138-2’.QTL mapping for submergence tolerance in soybean was carried out on the genetic linkage map provided by National Center for Soybean Improvement under the methods of composite interval mapping（CIM） and multiple interval mapping（MIM） of software WinQTL Cartographer Version 2.5.The genetic linkage map contained 488 SSR markers,spanning 25 linkage groups at a total distance 4226.4cM,with an average distance of 8.6cM between the flanking markers.The results from segregation analysis showed that submergence tolerance of soybean was controlled by three major genes with the heritability of 42.40%and no polygene detected.With composite interval mapping（CIM） and multiple interval mapping（MIM）,three QTLs associated with submergence tolerance were identified in both CIM and MIM,which located in Satt648～K418₂V,Satt531～A941V and Satt038～Satt275（B53B～Satt038） on linkage groups A1,D1a and G,respectively,explaining 4.4%～7.6%of the total phenotypic variation.The results from segregation analysis and QTL mapping appeared relatively consistent and could verify each other.However,there is some difference between the present results and those in the literature,therefore,further study is to be considered.更多还原