四个小麦抗穗发芽分子抗性标记有效性的验证与评价

成熟期穗发芽是一种世界性灾害, 严重影响小麦品质和产量。本试验利用已报道的4个与穗发芽抗性相关的标记, 即STS标记MST101、STMS标记wmc104、QTL位点Xgwm155与Vp1B3, 结合穗发芽率分析,对95份中国小麦地方品种和历史品种的穗发芽抗性进行筛选, 旨在从中筛选出抗穗发芽品种, 并对这4个分子标记的有效性进行比较, 筛选出可用于种质资源筛选和分子标记辅助育种的高效分子标记。结果表明, Vp1B3和Xgwm155与穗发芽抗性相关, 而MST101和wmc104与穗发芽抗性无关。比较而言, Vp1B3更能有效地用于筛选穗发芽抗性品种, 但将Vp1B3和Xgwm155结合起来筛选抗穗发芽小麦品种, 会提高选择效率。     

我国小麦主推品种穗发芽抗性鉴定及相关分子标记的评价

为了培育抗穗发芽品种,对我国10个小麦主产省份的75个品种进行了穗发芽抗性鉴定,同时利用3个分子标记Vp1B3、Xbarc310和Barc294对上述品种进行了分子检测。结果表明,不同品种间穗发芽抗性存在明显差异。Vp1基因的等位变异与穗发芽抗性关系不密切,Vp1B3标记难以用于品种的穗发芽抗性筛选。主效QTL(QPhs-3AS)与种子休眠关系密切,Xbarc310和Barc294可作为穗发芽抗性选择的重要参考,且Barc294较Xbarc310的选择效果好。上述结果为抗穗发芽小麦品种的改良和推广提供了重要信息。     

小麦穗发芽抗性的4个分子标记有效性检验

为筛选出适宜黄淮麦区和长江中下游麦区种植的抗穗发芽白粒小麦品种或种质资源,以36份黄淮麦区和长江中下游麦区的主要品种（系）及地方品种为研究对象,对已报道的4个与穗发芽抗性相关的分子标记：Vp1B3、Xgwm155、Xgwm269和Xbarc170进行有效性验证。测定参试材料种子萌发指数（GI）,并用上述4种标记进行PCR扩增,对扩增条带进行统计分析。结果表明,GI值显示,红粒品种（GI均值为5.1%）明显较白粒品种（GI均值为28.0%）低;4种标记扩增出的带型中仅Vp1B3的845 bp片段能有效地区分36份小麦品种(系);GI值筛选出6份抗穗发芽品种（系）中,其中3份为Vp1B3标记鉴定,可作为黄淮麦区和长江中下游麦区小麦穗发芽抗性育种中首选基因资源。     

小麦抗穗发芽研究进展

穗发芽对小麦的生产、加工和消费等方面带来诸多不利影响。小麦穗发芽受自身与环境因素的影响,其中子粒本身的休眠特性和α-淀粉酶活性与穗发芽联系紧密。近年来,利用分子标记和比较基因组学等方法研究小麦穗发芽发展迅速,已鉴定出大量与穗发芽抗性相关的分子标记,并定位到不同的染色体上。本文从穗发芽的危害、抗性机制、抗性遗传等方面阐述了小麦抗穗发芽的研究进展,并对今后重点研究方向进行了展望,以期为小麦抗穗发芽育种提供理论参考。     

西藏三联小穗小麦中三联小穗性状控制基因的SSR分子标记定位

西藏三联小穗小麦是中国西藏地区一种独特的小麦地方品种,拥有特殊的三联小穗性状,超多的小穗数和小花数。分子定位控制三联小穗基因的基因座,发掘与之紧密连锁的分子标记,可为小麦高产育种提供分子标记辅助选择工具。本研究利用西藏三联小穗小麦的衍生系TTSW-5与普通穗型小麦,间3和川麦55,分别构建F2群体,成熟后进行穗部性状的表型分析和SSR基因型鉴定。性状表型遗传分析表明,西藏三联小穗小麦的三联小穗性状由两个独立遗传的隐性基因控制;通过SSR标记鉴定来自TTSW-5/间3组合的F2群体,在2A染色体上检测到1个与三联小穗性状相关的QTL,定位于SSR标记Xgwm275和Xgwm122之间,两标记间的遗传距离为6.6cM,该QTL的LOD值为6.19,可解释的表型变异值为33.1%,初步命名为qTS2A-1。我们推测qTS2A-1可能是控制三联小穗性状相关的主效QTL,SSR标记Xgwm275和Xgwm122可能可用于三联小穗性状的辅助选择。     

小麦地方品种小白冬麦抗白粉病基因分子标记

小麦农家品种小白冬麦对小麦白粉病具有良好抗性,对病原菌拥有较广的抗谱,并与其他已知抗白粉病基因的抗谱不同,遗传分析证实小白冬麦的苗期抗性由一个隐性抗白粉病基因控制。为了寻找与小白冬麦所携带抗白粉病基因连锁的分子标记,采用小白冬麦和感病品种Chancellor(CC)正反交组合,在2个F₂群体125和107个单株上进行验证。结果显示,抗白粉病基因mlxbd与引物Xgwm577、Xgwm1267等紧密连锁,通过中国春及其第7部分同源群缺体-四体系,双端体系和缺失系将其定位在7B染色体长臂末端区域(7BL-10,Bin 0.78~1.00), 利用与mlxbd最近的引物Xgwm577扩增23个含有已知抗白粉病基因的小麦品种,检测发现这个引物不能单独用于分子标记辅助选择育种。     

以关联分析发掘小麦整穗发芽抗性基因分子标记

利用分布于小麦全基因组的181对分子标记,分析264份自然群体的基因型,采用TASSLE软件的GLM和MLM模型检测与整穗发芽抗性紧密关联的标记位点,发掘相关位点内的优异等位变异。在2012年和2013年室内整穗发芽率、2013年田间自然降雨整穗发芽率3个环境中,共关联到20个显著位点(P<0.05),分布于小麦染色体1AS、2DS、3AS、3BL、4AL、5AS、5BL、6BS、6DS、7AL和7BL上。分别位于2DS和7BL上的分子标记gwm102和barc340同时在3个环境下关联到,属于稳定的抗性位点; 另有6个标记位点同时在2个环境下关联到; 其余12个标记位点仅在1个环境下关联到。位于7BL上的barc340标记位点为一新报道位点。从重复关联的8个标记位点内共检测出10种优异等位变异。barc28-229bp和barc28-217bp对提高整穗发芽抗性效应最显著,主要分布在地方品种中(如遂宁坨坨麦等),而gwm102-142bp和barc186-199bp效应虽然相对较小,但多分布在推广品种中(如扬麦158等),有利于穗发芽抗性分子育种的直接应用。     

基于SLAF-seq技术开发长穗偃麦草染色体特异分子标记

长穗偃麦草1E及7E染色体上带有重要的抗赤霉病基因, 开发大量相关染色体特异分子标记有助于准确定位抗性基因及获得可用于辅助育种紧密连锁的标记。基于SLAF-seq技术, 获得了368个长穗偃麦草1E染色体特异片段, 随机选取80个特异片段设计引物, 开发了20个长穗偃麦草1E染色体特异分子标记、2个长穗偃麦草基因组特异分子标记及26个其他特异分子标记, 效率达60%。用这些特异标记能稳定检测出不同小麦–长穗偃麦草衍生材料中的1E染色体或片段。通过标记与优良性状的共分离特性, 获得与相关基因紧密连锁的标记, 将为小麦抗性育种中的分子标记辅助选择提供依据。     

分子标记Tamyb10D和TaDFR-B的有效性验证及对小麦抗穗发芽基因型的筛选

为了比较与小麦穗发芽抗性相关分子标记的有效性以及在白粒小麦品种中筛选出抗穗发芽的基因型材料,选择已报道的2个与穗发芽抗性相关的标记Tamyb10D和Ta DFR-B,对2套白粒小麦试材(78,103份)的穗发芽抗性进行综合筛选。结果表明:标记Tamyb10D可有效地用于白粒小麦穗发芽抗性筛选,而标记Ta DFR-B不适用于白粒小麦品种(系)材料的穗发芽抗性筛选的鉴定。通过分子标记Tamyb10D的筛选结果和发芽指数的评价,结合以前用分子标记Vp1B3的检测结果,在103份试材中筛选出5份具有高抗穗发芽基因型材料(GI10%),分别是:阆中白麦子、万县白麦子、陪陵须须白麦、川362和小白玉花,其单倍型分别是:Tamyb10D/Vp-1Bb、Tamyb10D/Vp-1Bb、Tamyb10D/Vp-1Bb、Tamyb10D/Vp-1Bb、Tamyb10D/Vp-1Bc;在另外一套(78份)试材中筛选出10份具高抗有穗发芽基因型材料(GI10%),分别为西农6028、克群、百农3217、开封124、郑州742、西昌5762、小偃5号、克壮、许跃6号和武农99,其单倍型均为Tamyb10D/Vp-1Bc。     

小麦骨干亲本繁6条锈病成株抗性特异位点及其在衍生品种中的遗传解析

基于已获得的控制小麦条锈病成株抗性“一致性”QTL区段80个SSR标记,结合小麦骨干亲本繁6及其衍生的39个后代小麦品种进行田间条锈病成株期抗性表型鉴定,揭示了骨干亲本繁6遗传物质及其成株抗性在其衍生品种的遗传规律。结果表明,骨干亲本繁6在条锈病条中31、32和33混合生理小种诱导下表现成株抗性,7个衍生后代品种表现全生育期抗性;用控制小麦条锈病成株抗性QTL区段的80个SSR标记对繁6及其后代衍生品种的其他亲本进行分子扫描,共发现9个来自繁6基因组的特异SSR标记,即Xwmc631、 Xgwm359、 Xwmc407、 Xgwm501、 Xgwm148、 Xgwm539、 Xgwm533、 Xgwm299和Xgwm639,其中,Xwmc631、 Xgwm359、 Xgwm501、 Xgwm299和Xgwm639在繁6衍生后代的4个子代中表现较高的遗传贡献率。以SSR标记与小麦条锈病成株抗性的关联分析发现6个SSR标记与小麦条锈病成株抗性显著相关,其中来自繁6的特异SSR等位变异Xgwm539-2D和Xgwm299-3B与严重度、反应型、普遍率、病情指数及病程曲线下面积(AUDPC)均具显著相关性,表明繁6的成株抗性及其控制遗传位点在其衍生后代品种选育过程中得到了很好的定向选择,并在西南麦区小麦条锈病抗性育种中发挥了重要作用。     

中国小麦微核心种质及地方品种籽粒休眠特性的分子标记鉴定

为探索我国小麦微核心种质及地方品种籽粒休眠的遗传基础,利用已报道的4个3AS上的SSR标记(Xbarc57、Xbarc294、Xbarc310和Xbarc321)和1个3BL上的Viviparous-1基因标记Vp1-b2对107份我国小麦微核心种质及31份地方品种进行籽粒休眠的分子标记鉴定。结果表明,5个分子标记在试验材料中表现出丰富的等位变异,具有5～6种等位类型,与籽粒萌芽指数(GI)密切相关。根据一般线性模型分析结果,各位点的等位变异显著影响籽粒休眠,其中Vp1-b2和Xbarc294对籽粒休眠作用较其他标记大,可分别解释65.8%和61.2%的表型变异;其次是Xbarc310(56.3%)和Xbarc57(55.8%),最小的是Xbarc321(53.3%)。而5个标记联合可解释95.9%的性状变异,其次是Vp1-b2和Xbarc294的组合(89.1%),解释变异最小的标记组合是Vp1-b2和Xbarc321(79.4%)。5个分子标记即可解释籽粒休眠的绝大部分表型变异,说明我国小麦微核心种质及地方品种籽粒休眠特性受3AS和3BL上的2个主效基因控制。     

Integration of marker-assisted selection for resistance to pre-harvest sprouting with selection for grain-filling rate in breeding of white-kernelled wheat for the Chinese environment

Few Chinese high yielding white-grained wheat cultivars possess sufficient dormancy to avoid pre-harvest sprouting (PHS). Because the field evaluation of PHS is difficult, the identification of informative molecular markers is a priority for improving the level of dormancy. In this report, the effectiveness of phenotypic and genotypic selection was compared. Four microsatellite loci Xbarc57, Xbarc294, Xbarc310 and Xbarc321, mapped on the short arm of chromosome 3A, were used for selection in white-grained wheat F₅ lines which were also selected on the basis of their grain filling rate (GFR). One of these (later designated cv. Zhongmai911) was further selected on the basis of its allelic constitution at the four SSR loci. This cultivar combines a high level of PHS resistance with high grain yield. The results suggested that rapid GFR and PHS resistance can be bred simultaneously.     

Simultaneous selection for yield-related traits and susceptibility to Fusarium head blight in spring wheat RIL population

Fusarium head blight (FHB), caused by the fungal plant pathogen Fusarium, is a fungal disease that occurs in wheat and can cause significant yield and grain quality losses. The present paper examines variation in the resistance of spring wheat lines derived from a cross between Zebra and Saar cultivars. Experiments covering 198 lines and parental cultivars were conducted in three years, in which inoculation with Fusarium culmorum was applied. Resistance levels were estimated by scoring disease symptoms on kernels. In spite of a similar reaction of parents to F. culmorum infection, significant differentiation between lines was found in all the analyzed traits. Seven molecular markers selected as linked to FHB resistance QTLs gave polymorphic products for Zebra and Saar: Xgwm566, Xgwm46, Xgwm389, Xgwm533, Xgwm156, Xwmc238, and Xgwm341. Markers Xgwm389 and Xgwm533 were associated with the rate of Fusarium-damaged kernels (FDK) as well as with kernel weight per spike and thousand kernel weight in control plants. Zebra allele of marker Xwmc238 increased kernel weight per spike and thousand kernel weight both in control and infected plants, whereas Zebra allele of marker Xgwm566 reduced the percentage of FDK and simultaneously reduced the thousand kernel weight in control and infected plants.     

小麦合成种M53抗白粉病基因的RAPD和SSR标记

运用RAPD和SSR技术，采用分离群体分组分析法(BSA)进行了小麦合成种M53抗白粉病基因连锁的分子标记研究。结果表明，M53的抗白粉病基因由显性单基因控制，RAPD标记OPL09-1700与抗病基因连锁，遗传距离为16.8cM。SSR标记Xgwm205也与抗白粉病基因连锁，遗传距离为9.3cM，通过SSR标记将该基因定位于5DS，标记与基因间的排列顺序     

Mapping quantitative trait loci in wheat for resistance against greenbug and Russian wheat aphid

Breeding for genetic resistance against greenbug and Russian wheat aphid (RWA) is the most effective way of controlling these widespread pests in wheat. Earlier work had shown that chromosome 7D of a synthetic hexaploid wheat, ‘Synthetic’ (T. dicoccoides × Ae. squarrosa) (AABB × DD) gave resistance when transferred into the genetic background of an aphid‐susceptible cultivar, ‘Chinese Spring’, as the recipient. To map the genes involved, a set of 103 doubled haploid recombinant substitution lines was obtained from crossing the 7D substitution line with the recipient, and used to determine the number and chromosomal location of quantitative trait loci (QTL) controlling antixenosis and antibiosis types of resistance. Antixenosis to RWA was significantly associated with marker loci Xpsr687 on 7DS, and Xgwm437 on 7DL. Antibiosis to greenbug was associated with marker loci Xpsr490, Rc3 (on 7DS), Xgwm44, Xgwm111, Xgwm437, Xgwm121 and D67 (on 7DL). Similarly, antibiosis to RWA was linked to loci Xpsr490, Rc3, Xgwm44, Xgwm437 and Xgwm121. At least two QTL in repulsion phase, one close to the centromere either on the 7DS or 7DL arms, and a second distal on 7DL could explain antibiosis to RWA and, partially, this mechanism against greenbug.     

小麦抗叶锈病基因Lr45的SSR分子标记

用定位于2A染色体的59对SSR、EST-SSR引物,对小麦抗叶锈病基因Lr45进行分子标记,共筛选出11对揭示TcLr45多态性的引物。用157株F₂抗感群体对这11对引物进一步检测,得到4个与Lr45共分离的SSR标记(Xgwm95、Xgwm47、Xgwm372和Xgwm122)。将经PAGE检测的标记Xgwm95的抗感差异带及Xgwm47的抗性片段进行克隆测序发现其中含有微卫星序列,且均为二核苷酸重复。Xgwm372和Xgwm122经琼脂糖凝胶电泳发现与Lr45的供体黑麦有共同的标记片段,可直接用于分子标记辅助选择。     

More precise map position and origin of a durable non-specific adult plant disease resistance against stripe rust (Puccinia striiformis) in wheat

Recently a major gene determining non-specific adult plant disease resistance against stripe rust (Puccinia striiformis) designated Yrns-B1 was mapped in wheat Triticum aestivum L. by using a cross between ‘Lgst. 79-74’ (resistant) and ‘Winzi’ (susceptible). Linkage to five Gatersleben wheat microsatellite (GWM) markers was discovered, previously mapped on chromosome arm 3BS. In the present study this map was improved by the incorporation of four additional GWM markers. QTL-analysis revealed high LOD values for the resistance at all nine loci, whereas the largest LOD (20.76) was found for the newly mapped marker Xgwm1329. Microsatellite analysis and resistance tests of a collection of old German/UK wheat varieties, including probable ancestors of ‘Lgst.79-74’ were carried out. A high coincidence of non-specific adult plant disease resistance against stripe rust and the presence of ‘Lgst. 79-74’ allele (117 bp) of the marker Xgwm533 was observed among the varieties tested. Linkage during the inheritance of both the resistance and the 117 bp allele of Xgwm533 was demonstrated. The probable origin of Yrns-B1 is discussed. Carriers of this resistance gene were grown on large areas since more than 100 years. To estimate the capability of Xgwm533 as a diagnostic marker for non-specific adult plant disease resistance against stripe rust, microsatellite analysis and resistance tests of a collection of Russian spring wheat varieties were performed. The 117 bp allele of Xgwm533 was found in about 35% of the Russian cultivars analysed, however, none of them possessed the expected disease resistance. Thus, the utilisation of Xgwm533 as diagnostic marker seems to be restricted to certain genepools.