燕麦DNA导入普通小麦变异观察及RAPD分子验证

利用花粉管通道将健壮燕麦(Avera sativaL.)的总DNA导入普通小麦宁春4号中,获得12个稳定变异的品系。农艺性状变异观测结果显示多数变异品系的叶面积、穗长、主穗粒数、主穗粒重和千粒重等性状都显著地超过了受体宁春4号小麦;对受体、供体和稳定变异的品系进行RAPD分析,在68个随机引物中有8个引物检测出DNA的多态性,并且在后代基因组中找到了受体没有而供体特有的DNA片段,从DNA分子水平上证明了燕麦DNA可以通过花粉管通道进入受体,并与其基因组DNA整合,在后代中遗传和表达。     

2008-2009年度河北、河南、四川和江苏四省冬小麦区试品系的遗传多样性和抗条锈性分析

探讨2008-2009年度河北、河南、四川、江苏四省参加区试的70个小麦品系的遗传多样性和抗条锈性,以期了解小麦种质资源间的遗传差异,并为小麦品种抗条锈病基因的合理布局提供科学依据。采用亲缘系数（coefficient of parentage, COP）分析2008-2009年度四省的70个供试小麦品系的2 415对组合并进行聚类分析,同时,对这70个品系接种条锈菌混合菌系CYR32、CYR31、CYR33、CYR30和CYR29,进行抗条锈性鉴定。供试的所有品系的COP值的变化范围在0.000 0～0.750 0之间,COP值的总和为24.607 5,其平均值为0.010 2。聚类分析分为6大类,聚为一类的多为同一个骨干亲本培育的品系且它们的抗性相似,说明使用同一骨干亲本抗病性得到了较好的遗传,但使用同一亲本降低了小麦品种间的遗传多样性。增大对亲缘关系较远的品种的应用,有利于增加小麦品种间的遗传多样性,创造出更多的优异种质。小麦条锈病抗性鉴定结果表明,四省的小麦区试品系对条锈病感病和抗病分别占总参试品系的57.14%和40%,其中,四川抗病品系占参试品系的61.55%,总体上看抗条锈性相对较好,其他三省抗条锈性相对较差,抗病品种选育工作亟待加强。     

陇南小麦条锈病的品种遗传多样性控制

为实现陇南小麦条锈病持续控制的目标,以遗传多样性为原则,组建以提高生产品种抗条锈基因丰富度、在锈菌越夏区和越冬区进行基因布局和持久抗性、慢条锈性、高温成株抗性等多种抗性利用为主要内容的控制技术体系。利用Yr10、Yr12、Yr13、Yr16、Yr26、YrC591等有效抗条锈基因的载体品种、Flinor 等持久抗性品种及中四等其它抗源材料育成一批综合性状优良、具有不同遗传背景的抗病品种和类型,其中2004年以来育成的10个品种产量性状有明显提高,在区域试验中较对照增产7.3%~28.9%。陇南小麦条锈病的控制已进入一个新阶段。     

10份小麦持久抗性资源和6份新品系抗条锈病的遗传特点分析

小麦条锈病是长期威胁我国小麦生产安全的重要气传病害。由于病原菌(Puccinia striiformis f.sp.tritici,Pst)群体毒性结构高度变异,我国小麦条锈病防治工作经常面临严峻挑战。培育和广泛利用抗病品种是防治小麦条锈病最为经济有效的措施。因此,鉴定抗源和探究持久抗病基因型的遗传模式能为抗病育种提供抗病新基因和理论指导,具有重要意义。我国部分持久抗条锈病的小麦品种和新育成抗病品系的抗性遗传特点尚未明确,本研究中以这些抗病品种或品系作父本,高感病品种‘Taichung 29’或‘铭贤169’作为母本进行有性杂交,构建遗传群体,在成株期利用条锈菌优势小种CYR32进行接种鉴定,分析其抗病性遗传组分及遗传特点。在10个持久抗条锈病品种中,多数品种(8个)由1对或2对隐性遗传基因控制;6个新育成抗病品系中,多数(4个)含有单个抗病基因,隐性或显性遗传偏向性不明显。因此,隐性遗传抗病基因在持久抗条锈病品种中发挥更重要的作用。另外,新育成品系‘WJ10-97’对CYR32号小种具有慢条锈性特点,可作为新抗源用于小麦品种选育。     

冬小麦品种陇鉴9821抗条锈遗传分析

 冬小麦品种陇鉴9821是以甘肃陇南感病生产品种洮157为受体,以高粱总体DNA为供体系统选育而成,具有较好的丰产性和抗条锈性。本文对陇鉴9821抗条锈性及其遗传特点进行了研究,结果表明：苗期抗条锈基因推导分析得出,陇鉴9821对供试菌系的抗性谱与已知基因不同,含有未知抗条锈病基因;遗传分析显示对CYR29和CYR33的抗病性均由1对显性基因控制;通过抗病性鉴定和抗谱比较分析,认为陇鉴9821对CYR29和CYR33表现显性抗病性的基因是2对不同的抗条锈病基因,其中1对来自洮157。陇鉴9821可作为生产品种及抗源材料在生产上利用。     

小麦材料PI31抗条锈性鉴定及其抗性基因SSR标记

 小麦材料PI31对我国当前流行的条锈菌小种条中30、31和32免疫;遗传分析表明,PI31携带一个显性抗条锈病基因。等位性测定显示,PI31所携带的抗条锈病基因与已知抗锈基因Yr5、Yr10和Yr15不等位。抗源系谱分析表明,该基因来源于叙利亚普通小麦品系叙18;故将此材料携带的抗条锈病基因暂定名为Yr-XU。利用分组分析(BSA)法,筛选到1个位于1 BS的SSR标记WM S11-193 bp片段与Yr-XU紧密连锁,将Yr-XU定位于小麦1BS上;对F₂分离群体142个单株分析结果表明,Yr-XU与WM S11-193 bp的遗传距离为2.1 cM,可将此标记用于小麦抗条锈病分子标记辅助育种。     

印度圆粒小麦抗条锈病新基因YrSph的遗传分析和SSR标记定位

 抗条锈病小麦新种质D31是以印度圆粒小麦（Triticum sphaerococcum Perc.）AS384与普通小麦品系94-3854杂交、回交选育而成的新品系。用中国小麦条锈病菌（Puccinia striiformis f.sp. stritici）流行生理小种条中32号对D31和Taichung29的杂交后代进行苗期及成株期抗条锈性遗传分析。结果表明,D31对生理小种条中32号表现为全生育期近免疫抗性反应,其抗性由1对隐性基因控制,暂命名为YrSph。利用BSA法对构建的F²遗传作图群体进行SSR标记分析。通过对400对微卫星引物的筛选和群体分析表明,抗性基因与 Xwmc149、Xwmc246、Xgwm372和Xwmc198 具有连锁关系,其中与 Xwmc246 标记连锁较近,遗传距离为8.8 cM。基因和标记之间的顺序为 Xwmc149-YrSph-Xwmc246-Xgwm372-Xwmc198 。根据作图结果,将D31所含的抗条锈病基因YrSph定位于2A短臂上。基于该基因的作图位置与系谱分析,认为该基因可能是1个新的抗条锈病基因。     

小麦品系P81抗条锈性遗传分析

小麦条锈病是小麦生产中最重要的病害,培育抗病品种是防治条锈病的有效措施。小麦品系P81在苗期和成株期对当前流行的条锈菌小种条中30、31和32均表现免疫。以感病品种川麦28、Taichung29作母本,P81作父本通过杂交分别配制了F1、F2和BC1、BC2代,用人工接种方法研究P81及其杂交后代对条中32号的苗期抗性并进行了遗传分析;同时,将P81分别与含有抗条锈基因的Yr5、Yr10、Yr15、Yr26材料进行杂交配制F2,用条中32号小种对其F2进行抗感鉴定,确定抗性基因的等位性。结果表明,P81与川麦28、Taichung29杂交F1代植株对条锈菌条中32号小种表现出与P81相似的高抗,说明P81中的抗条锈基因为显性表达。根据P81与川麦28、Taichung29杂交的F2、BC1、BC2代植株的抗性分离情况及F1代植株及亲本的抗性表现,说明P81对条中32号的抗性由1对显性抗条锈病基因控制;用条中32号小种接种鉴定P81与已知抗锈基因Yr5、Yr10、Yr15、Yr26构建的F2群体时均出现了感病植株,说明P81中的抗条锈病基因与Yr5、Yr10、Yr15、Yr26不相同;系谱分析表明,该基因来源于叙利亚普通小麦品系叙29。     

青海春小麦品种‘青春38’成株期抗条锈性遗传解析

为明确青海春小麦品种‘青春38’成株期抗条锈性的遗传基础,以‘青春38’为父本与感病春小麦品种‘Taichung 29’(T29)杂交构建F2∶3代分离群体。在青海西宁和互助两地田间病圃进行了抗条锈性鉴定,应用植物数量性状主基因+多基因混合遗传模型单个分离世代分析方法,解析‘青春38’的抗条锈性遗传特点。结果表明,‘青春38’/‘T29’F2∶3群体单株的病害严重度和反应型在两个试验点均未呈现连续性分布,也不符合正态分布,初步推测‘青春38’对小麦条锈病的成株期抗性具有质量性状特征;以严重度或反应型数据进行遗传分析,‘青春38’在两个试验点对小麦条锈病的成株期抗性表现的最优遗传模型均属2对主基因遗传,只是主基因的作用方式(C-1:2MG-ADI加性-显性-上位性,C-4:2MG-EA等加性,C-6:2MG-EEAD等显性)有所不同。     

小麦抗条锈品种遗传多样性的SSR分析

［目的］ 利用SSR标记分析我国几大小麦产区主栽品种中抗锈品种的遗传多样性,为小麦抗条锈育种亲本材料的选择提供参考。［方法］ 以当前条锈菌优势小种接种成株期小麦,从几大小麦产区主栽品种中筛选出抗条锈品种。然后利用SSR标记对筛选出的抗锈品种的遗传多样性进行分析。［结果］ 27对SSR引物在上述抗锈品种中共检测到104个等位变异,平均为3.85个;引物的多态信息含量（PIC）在0.210~0.712之间,平均为0.455;抗锈品种间遗传相似系数平均为0.723,表明筛选出的抗锈品种遗传多样性较低,亲缘较近。［结论］ 聚类分析的结果将抗锈品种分为了4个类群,类群的分布与亲缘的远近和品种的地域有一定的相关性。     

Molecular approaches for characterization and use of natural disease resistance in wheat

Wheat production is threatened by a constantly changing population of pathogen species and races. Given the rapid ability of many pathogens to overcome genetic resistance, the identification and practical implementation of new sources of resistance is essential. Landraces and wild relatives of wheat have played an important role as genetic resources for the improvement of disease resistance. The use of molecular approaches, particularly molecular markers, has allowed better characterization of the genetic diversity in wheat germplasm. In addition, the molecular cloning of major resistance (R) genes has recently been achieved in the large, polyploid wheat genome. For the first time this allows the study and analysis of the genetic variability of wheat R loci at the molecular level and therefore, to screen for allelic variation at such loci in the gene pool. Thus, strategies such as allele mining and ecotilling are now possible for characterization of wheat disease resistance. Here, we discuss the approaches, resources and potential tools to characterize and utilize the naturally occurring resistance diversity in wheat. We also report a first step in allele mining, where we characterize the occurrence of known resistance alleles at the wheat Pm3 powdery mildew resistance locus in a set of 1,320 landraces assembled on the basis of eco-geographical criteria. From known Pm3 R alleles, only Pm3b was frequently identified (3% of the tested accessions). In the same set of landraces, we found a high frequency of a Pm3 haplotype carrying a susceptible allele of Pm3. This analysis allowed the identification of a set of resistant lines where new potentially functional alleles would be present. Newly identified resistance alleles will enrich the genetic basis of resistance in breeding programmes and contribute to wheat improvement.     

Pyramiding of partial disease resistance genes has a predictable,but diminishing,benefit to efficacy

Partial resistance genes often need to be ‘pyramided’ into a crop cultivar to obtain commercially acceptable levels of disease resistance. Analysis of data from four different wheat mapping populations, segregating for partial resistance to four contrasting foliar pathogens, showed a diminishing benefit to disease control from increasing the numbers of resistance loci in wheat lines. To test whether a general function could describe the efficacy benefit from pyramiding, a simple multiplicative survival model (MSM) was used to predict disease severities on mapping population lines carrying various combinations of two, three or four resistance loci. The effectiveness of each resistance locus was expressed as the disease severity in lines carrying resistance alleles at one locus, as a proportion of the severity in lines carrying no detectable resistance alleles. The predicted severity from any given combination of multiple resistance loci was calculated as the product of the proportional severities for the relevant single loci. A regression line fitted to transformed observed against predicted values explained 93% of the variation, with a slope and intercept not significantly different from 1 and 0, respectively. MSM may therefore provide a simple method to test contrasting types of partial resistance and search for synergistic combinations. The analysis suggests that diminishing returns are a general feature of partial resistance to foliar pathogens in wheat, a finding that is likely to apply to other crop pathosystems. Identifying and combining ever more QTL is likely to provide limited gains. The consequences of these findings for QTL analysis are described.     

High Genetic Similarity Among Populations of Phaeosphaeria nodorum Across Wheat Cultivars and Regions in Switzerland

ABSTRACT Phaeosphaeria nodorum was sampled from nine wheat fields across a 30-km transect representing three geographical regions in Switzerland to determine the scale of genetic differentiation among subpopulations. Three different wheat cultivars were sampled three times to determine whether differences in host genotype correlated with differences among corresponding pathogen populations. Seven restriction fragment length polymorphism (RFLP) loci and one DNA fingerprint were assayed for each of the 432 isolates in the collection. DNA fingerprints differentiated 426 unique genotypes. Though absolute differences were small, five RFLP loci exhibited significant differences in allele frequencies across the nine sub-populations. Gene diversity within all subpopulations was high (H(T) = 0.51), but only 3% of the total genetic variation was distributed among the nine subpopulations. When subpopulations were grouped according to geographical region or host cultivar, less than 1% of the genetic variation was distributed among groups, suggesting widespread gene flow and the absence of pathogen adaptation to specific wheat cultivars. Tests for gametic equilibrium within subpopulations and across the entire Swiss population supported the hypothesis of random mating.     

A Single Gene Cluster Controls Incompatibility and Partial Resistance to Various Melampsora larici-populina Races in Hybrid Poplars

ABSTRACT Complete cosegregation for race-specific incompatibility with three Melampsora larici-populina rust races was observed in five F(1) hybrid progenies of Populus, with different patterns among the various progenies. A single gene cluster could explain these segregations: one locus with multiple alleles or two tightly linked loci controlling complete resistance to E1 and E3, and two tightly linked loci for E2. The random amplified polymorphic DNA marker OPM03/04_480 was linked to that cluster in all families (<1 cM). This marker accounted for more than 70% of the genetic variation for field resistance in each family (heritability approximately 0.40). The same marker accounted for up to 64% of the clonal variation for growth in the nursery under natural inoculum pressure; the weak tolerance to rust of F(1) interspecific hybrids was attributed to a genetic background effect. Partial resistance was split into epidemiological components (heritability ranged from 0.35 to 0.87). Genotypic correlations among resistance traits for the different races were high (0.73 to 0.90). However, correlations among different resistance components for a single race were not all significant. A major quantitative trait locus for all components of partial resistance to E2 was associated to the cluster controlling incompatibility to E1 and E3 and marked by OPM03/04_480 (R(2)from 48 to 68%).     

Main effects, epistasis, and environmental interactions of quantitative trait Loci for fusarium head blight resistance in a recombinant inbred population

ABSTRACT Chinese Spring Sumai 3 chromosome 7A disomic substitution line (CS-SM3-7ADS) is highly resistant to Fusarium head blight (FHB), and an F(7) population of recombinant inbred lines derived from the cross CS-SM3-7ADS x Annong 8455 was evaluated for resistance to FHB to investigate main effects, epistasis, and environmental interactions of quantitative trait loci (QTLs) for FHB resistance. A molecular linkage map consists of 501 simple sequence repeat and amplified fragment length polymorphism markers. A total of 10 QTLs were identified with significant main effects on the FHB resistance using MapQTL and QTLMapper software. Among them, CS-SM3-7ADS carries FHB-resistance alleles at five QTLs on chromosomes 2D, 3B, 4D, and 6A. One QTL on 3BS had the largest effect and explained 30.2% of the phenotypic variance. Susceptible QTLs were detected on chromosomes 1A, 1D, 4A, and 4B. A QTL for enhanced FHB resistance was not detected on chromosome 7A of CS-SM3-7ADS; therefore, the increased FHB resistance in CS-SM3-7ADS was not due to any major FHB-resistance QTL on 7A of Sumai 3, but more likely was due to removal of susceptible alleles of QTLs on 7A of Chinese Spring. QTLMapper detected nine pairs of additive-additive interactions at 17 loci that explained 26% phenotypic variance. QTL-environment interactions explained 49% of phenotypic variation, indicating that the environments significantly affected the expression of the QTLs, especially these epistasis QTLs. Adding FHB-enhancing QTLs or removal of susceptible QTLs both may significantly enhance the degree of wheat resistance to FHB in a wheat cultivar.     

甘肃冬小麦高分子量麦谷蛋白亚基组成及其品质现状分析

对近年来甘肃冬麦区新育成和引进的72份冬小麦新品种(系)的高分子量麦谷蛋白亚基(HMW-GS)进行了检测和品质评价。结果表明:HMW-GS的组成中,Glu-A1位点的3种亚基类型(Null、1、2~*)均有分布;Glu-B1位点主要存在5种亚基类型/组合,即7+8、7+9、6+8、13+16、20x+20y;Glu-D1位点存在Null、 2+12、5+10三种亚基类型/组合;其中,优质亚基/组合1、2~*、13+16、5+10出现的频率分别为70.83%、2.78%、1.39%和33.33%。近年来甘肃冬小麦品质改良育种工作成效显著,1和7+8优质亚基频率明显提高,49个新品种(系)以1/7+8/2+12亚基组合类型为主,占44.90%;1/7+8/5+10优质亚基组合类型在新品种(系)中较少(12.24%)。因此,进一步将14+15,13+16和5+10等优质亚基导入甘肃冬麦区主栽品种,培育优质小麦新品种(系)对甘肃陇东地区小麦品质改良具有重要意义。     

海南稻作区稻瘟病菌AvrPik等位基因的变异监测与多样性分析

海南省地处热带。由于具有国内其他地区无可比拟的光温资源优势,每年有大量的水稻材料在南繁区繁育与种植,给稻瘟病菌的变异及传播带来了极大的便利。自20世纪70年代以来,Pik等位基因已被广泛地用作水稻抗稻瘟病育种的主要抗源。为了解海南稻瘟病菌AvrPik等位基因的变异及多样性,本研究从海南稻作区采集穗茎瘟病样,通过单孢分离获得100株稻瘟病菌株。利用AvrPik基因特异性引物扩增病原菌DNA,所得PCR产物经克隆、测序后与参考序列进行比对分析。结果从100株菌株中鉴定出AvrPik＿A、AvrPik＿B、AvrPik＿D、AvrPik＿E和AvrPik＿F共5种等位基因类型。其中AvrPik＿D类型最多,出现频率为50.00%;其次为AvrPik＿E类型,出现频率为32.08%;第三为AvrPik＿B类型,出现频率为8.49%。在AvrPik等位基因核苷酸多样性方面,非信号肽区域多样性要明显高于信号肽区域。就群体受到的选择压而言,南繁种植区与常规种植区的稻瘟病菌群体的Ka/Ks值均大于1,分别为2.703 1和1.236 6,表明,无论是南繁区还是常规种植区,AvrPik等位基因均受到了强...     

The effect of homoeologous group 7 chromosomes upon adult plant resistance of wheat to yellow rust (Puccinia striiformis)

Aneuploid and intervarietal chromosome substitution lines of wheat ev. Chinese Spring were used to study the effects of homoeologous chromosomes 7A, 7B and 7D upon adult plant resistance to yellow rust ( Puccinia striiformis). Chromosomes 7B and 7D carry factors upon their short arms which interact to influence resistance. The results can be explained if there is a single locus determining resistance upon the short arms of chromosomes 7B and 7D. These loci may be homoeo-allelic; however, no evidence was found for a corresponding locus upon the short arm of chromosome 7A. Three homologous variants of the factor on 7D^S were found but no variation was found for the factor on 7B^S.     

河北省小麦全蚀病菌变种类型鉴定

2007年从河北省的保定、石家庄、邢台小麦主产区采集小麦全蚀病株,共分离得到62个菌株,对其所属的变种类型进行了形态学和分子生物学鉴定。根据形态、培养性状、生理特性以及在小麦、高粱、水稻、玉米、燕麦等禾本科作物上的致病性,初步认定测定的所有菌株均为禾顶囊壳小麦变种(Gaeumannomyces graminisvar.tritici)。进一步采用4个变种的特异性引物进行PCR扩增,在所有菌株中扩增出870bp的条带,该片段为禾顶囊壳小麦变种特异性片段,证实所测菌株均为禾顶囊壳小麦变种。