硬粒小麦与偏凸山羊草部分双二倍体的核型研究

通过硬粒小麦（AABB，2n＝28）与偏凸山羊草（DDMvMv，Zn＝28）杂交，今成选育出遗传上相对稳定的部分双二倍体。利用核型分析，初步鉴定出该部分双二倍体具有编凸山羊草的染色体组，从而证实了杂种的真实性。该部分双二倍体的获得为将硬粒小麦，特别是偏凸山羊草的优异基因向小麦转移奠定了基础。     

普通小麦——偏凸山羊草5 MV染色体易位系核型分析及其遗传稳定性评价

采用形态学及细胞学方法，对普通小麦-偏凸山羊草5M^V染色体易位系的遗传稳定性进行了分析，1504后代的核型公式为2n=6x=42=34（2SAT）＋8sm（2SAT），减数分裂中期Ⅰ染色体构型为20．25Ⅱring＋0．74Ⅱrod＋0．00Ⅰ。经初步推断，来自于偏凸山羊草的抗性基因已经能够在1504易位系中得到稳定遗传。     

麦田杂草节节麦染色体核型分析研究

对麦田杂草二倍体节节麦（Triticum tauschii L．）的植株形态特征及根尖细胞染色体核型作了分析，并和六倍体普通小麦（Triticum aestivum L．）中国春核型作比较。结果表明，节节麦的核型公式为2n=2X=14=10M＋4SM（2SAT），在第4号染色体上有一对随体。节节麦染色体组和普通小麦中国春D组全套染色体类型相同，表明这两组染色体具有较强的同源性；但二者在染色体相对长度和臂比值上表现出一定的差异，表明该地区节节麦未参与普通小麦的起源。     

小伞山羊草与硬粒小麦和偏凸山羊草的细胞学鉴定

利用小伞山羊草作母本,分别与硬粒小麦和偏凸山羊草进行杂交,得到杂种F1。花粉母细胞观察结果表明,小伞山羊草与硬粒小麦的杂种F1中期染色体为21I;小伞山羊草与偏凸山羊草的杂种F1中期染色体为3Ⅱ＋15I。研究证明了小伞山羊草与硬粒小麦和偏凸山羊草杂种的真实性。为进一步将小伞山羊草中的有利基因向普通小麦转移提供了新的育种材料。     

提莫菲维小麦染色体的C-带分析

对提莫菲维小麦的根尖细胞染色体进行C-带分析,以明确提莫菲维小麦的染色体C-带带型特点。结果表明:提莫菲维小麦具有14对染色体,其染色体带型公式为:2 n=28=4 IT++4 IT++6 CIT++6 I+2 IT+2 CI+2 CIT+S+2 CIS,共包括98条带,其中长臂具有57条带纹,包括50条中间带(I),7条端带(T);短臂具有35条带纹,包括30条中间带(I),3条端带(T),2条随体带(S);另外还有着丝点带(C)6条。提莫菲维小麦G组染色体的异质化程度明显高于A组染色体,G组染色体的C-带带型与普通小麦B组染色体非常相似,因此G组染色体可能与B组染色体存在部分同源性。     

节节麦-黑麦双二倍体的染色体C-带分析

通过对节节麦-黑麦双二倍体及其亲本节节麦、黑麦的C-分带研究,表明节节麦-黑麦双二倍体含有其双亲完整的染色体组,其C-带带型与亲本的C-带带型基本一致,从细胞学水平上证实了该种质是人工合成的一种新的异源多倍体。     

川麦42遗传背景中人工合成小麦导入位点的SSR标记检测

硬粒小麦和节节麦是六倍体普通小麦的二级基因源,六倍体人工合成小麦遗传变异丰富、蕴藏着丰富的抗性基因,可供现代小麦改良利用。利用人工合成小麦基因资源与四川小麦杂交、回交,已育成了高产、优质、抗病小麦新品种“川麦42”。本文利用217对微卫星（SSR）引物检测“川麦42”遗传背景中人工合成小麦的导入位点,发现24个位点来源于人工合成小麦,占所用引物数的11.06%,远小于理论值25%。川麦42遗传背景中人工合成小麦导入位点在A、B和D染色体组分布频率不均衡,D组>B组>A组;人工合成小麦导入位点在川麦42各染色体间差异也很大,在1B、2B和5A染色体上分布较集中、片段较长,而在1A等11条染色体上则无导入位点;表明人工合成小麦的遗传位点并不按孟德尔遗传规律传至后代,人工选择压力导致遗传位点很大的偏分离行为。     

抗禾谷孢囊线虫小麦新种质H3714和H4058的培育与鉴定

在我国小麦主产区均有禾谷孢囊线虫(CCN,Heterodera spp.)发生。限于有效抗源的严重匮乏,抗CCN育种研究一直难以规模化开展。Madsen是一个抗孢囊线虫的美国冬小麦品种,但抽穗偏晚使其很难在育种上迅速利用。本研究利用中国小麦品种烟农21和济麦19与Madsen杂交和回交,从BC1F4代中选育出稳定品系H3714和H4058。田间病圃和温室接种鉴定结果表明,这2个品系对河南省H.avenae荥阳群体(致病型Ha43)和H.filipjevi许昌群体(致病型Hfc-1)的抗性显著优于烟农21和济麦19。在接种条件下,两个品系表现成株期白粉病抗性,H4058苗期还可抗不同白粉菌菌株。2个品系的抽穗期与烟农21和济麦19相似,明显早于Madsen。利用偏凸山羊草2NS染色体特异分子标记VENTRIUP-LN2及该染色体上Vrga1D基因特异分子标记Vlr2.6-3′-Vlr2.4-5′和VRGA-F11-VRGA-R5分析,发现H3714和H4058含有偏凸山羊草2NS染色体片段,且该染色体片段来自Madsen。根据Illumina i Select 90K SNP分析结果,两个品系的染色体构成存在差异。在检测到两个品系共有的4918个多态性SNP中,2/3的SNP位点在2个姊妹系间表现相同,另外1/3的SNP位点表现不同。本研究培育的抗禾谷孢囊线虫小麦新种质H3714和H4058可作为培育抗线虫小麦品种的抗源。     

小麦D基因组产量性状QTL定位

粗山羊草是普通小麦的D染色体组供体,为了寻找粗山羊草中对小麦产量性状遗传改良有益的基因,通过对四倍体硬粒小麦与粗山羊草杂交合成的双二倍体Am6-1和普通小麦品种Ph85-16的回交一代进行产量性状变异特点分析,发现粗山羊草的D组染色体对小麦的产量性状具有显著影响,千粒重、穗长、穗粒数和每穗小穗数明显高于Ph85-16;同时利用130对SSR引物对几个与产量性状相关的QTL位点进行了定位,初步寻找到4个主效QTL,它们分别为与穗长相关的QSl．sdau-5D,其贡献率为31．58％,与株高相关的QPh．sdau-1D,其贡献率为25．38％,与穗粒数相关的QGs．sdau-5D,其贡献率为44.65％,与千粒重相关的QTgw．sdau-3D,其贡献率为61．62％。     

四倍体小麦矮杆地方品种的C带分析

矮杆番麦是四倍体小麦地方品种罕见的矮杆种质,采用改主的Ｃ带技术对基尖细胞染色体进行了分析,矮杆番麦体细胞具１４对染色体,染色体组型ＡＡＢＢ。非同源染色体之间,带的数目,大小,强弱及分布情况各异,根据其特殊的带型,容易将筹杆番麦的单条染色体及分开,据此认为Ｃ带可作为矮杆番麦染色体的细胞学标记,矮杆番麦的带型与原始类型的野生二粒小麦相似,表明其基因未发生过大的染色体重排,因此,矮杆番麦的矮杆性状不是由     

Variation for apparent amylose content of endosperm starch in Triticum durum and Aegilops squarrosa

For breeding to increase amylose content in the starch of hexaploid wheat, either the introduction of genes from Aegilops squarrosa (DD genome) or the development of high-amylose amphiploids between Triticum durum (AABB genome) and Ae. squarrosa is one of the most efficient ways. The high-amylose genes have not been detected in any species of Triticum and Aegilops. Therefore, we assessed the apparent amylose content in endosperm starch of T. durum and Ae. squarrosa accessions supplied from the major gene banks from world wide, and found several accessions with higher amylose content out of 665 T. durum accessions and out of 732 Ae. squarrosa accessions. Genetic analysis indicated that a high amylose trait in Ae. squarrosa is monogenically inherited by a recessive major gene. This revised version was published online in July 2006 with corrections to the Cover Date.     

Endopeptidase EP-1 as a Marker for the Eyespot Resistance Gene Pch-1 from Aegilops ventricosa in Wheat Line 'H-93-70'

Biochemical marker endopeptidase EP-1 was used to determine that an eyespot resistance gene, transferred from Aegilops ventricosa to the hexaploid wheat line ‘H-93-70’ is located on the long arm of the chromosome 7D.     

小麦(T.aestivum L.)D基因组的研究进展

普通小麦是一个异源六倍体物种,具有ABD三个染色体组,D染色体组在来源和进化过程中都与A、B染色体组不同,D染色体组来自于粗山羊草,含有丰富的抗病、抗虫、抗寒、优质等有益基因,因此D染色体组的研究对小麦的产量、品质改良具有重要意义。但是由于长期的定向遗传改良,我国普通小麦的遗传差异较小,遗传基础狭窄,特别是在D染色体组上尤为突出。一些对作物产量和品质有益的基因未被挖掘利用。本文对小麦D基因组的起源、遗传多样性和拓宽遗传基础的方法及基因定位等进行了综述,并结合本实验室的研究工作对其研究前景进行展望。     

山羊草谷胱甘肽S-转移酶基因家族鉴定及表达分析

谷胱甘肽S-转移酶是一种多功能蛋白酶,在植物体内参与干旱、盐、低温、重金属等多种非生物胁迫的调节;山羊草是普通小麦D染色体组的供体物种,深入挖掘山羊草中GST基因,对进一步分析六倍体小麦GST基因的功能具有重要意义。本研究利用信息生物学手段,在山羊草中共发现114条GST基因序列,分属于6个亚族;基因复制分析发现共4对基因发生了基因复制,且均为纯化选择;采用荧光定量PCR对部分GST基因在非生物胁迫下的表达分析发现,8个GST基因在响应干旱和盐胁迫时,主要在根部显著上调表达,3个GST基因在响应低温胁迫时,在根和叶中均显著上调表达,说明山羊草中的GST基因在应答非生物胁迫时,在不同组织中的表达存在着差异。     

小麦抗白粉病新基因的AFLP和SSR标记及其染色体定位

M53 (YAV2/TEZ//Ae.squarrosa 249) 是硬粒小麦与粗山羊草的双二倍体合成种,携带一个抗白粉病新基因,暂命名为Pm-M53,该基因对北京地区白粉病优势生理小种15号表现免疫抗性。本研究利用来源于杂交组合M53/宛7107的一个F₂群体,在苗期采用白粉病15号小种（Blumeria graminis f. sp. tritici）接种,抗病反应型鉴定表明,抗感比例符合3∶1,说明其抗性受显性单基因控制;对部分F₂植株的F₃株系的抗病鉴定进一步证明了F₂鉴定的可靠性;利用AFLP和SSR标记技术结合F₂分离群体对目的基因进行了遗传作图,将目的基因定位在5D染色体的长臂上。其中AFLP标记P16M16_-109(Apm109)和P5M16_-161(Apm161)与目的基因的遗传距离分别为1.0和3.0 cM。SSR标记Xwmc289b、Xgwm583和Xgwm292与目的基因的遗传距离分别为20.0、33.0和24.0 cM。这些标记位于目的基因的两侧。利用中国春遗传背景的缺-四体和双端体结合AFLP标记Apm109确证了SSR标记定位的可靠性,进一步证明该基因是一个新的抗白粉病基因。     

Effect of genome and ploidy on photosynthesis of wheat

We assessed (1) the effects of addition and doses of the D genome from different sources and (2) the addition of either the A genome or the D genome on the photosynthesis of synthesized hexaploid wheats. On average, the increased doses of the D genome reduced photosynthesis, but the depression was dependent on the source of the D genome. Two accessions of Aegilops squarrosa had depressed photosynthetic rates, but not another accession of Ae. squarrosa. The D genome of cv. Thatcher did not contribute to depress photosynthetic rate. Triticum monococcum had considerably higher photosynthetic rates than Ae. squarrosa. However, addition of the A genome from T. monococcum did not increase the photosynthetic rates of hexaploids. Chlorophyll a : b ratio, functional photosystem II and the core complex of photosystem II did not account for the variation in photosynthetic rate among the genotypes studied. In our experiment, photosynthesis of polyploids was not dependent on photosynthesis rates of the donor genomes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Expression of nucleolus, endosperm storage proteins and disease resistance in an amphiploid between Aegilops tauschii and Secale silvestre

Cytology and gene expression of an amphiploid between Aegilops tauschiiL., native to China, and Secale silvestre L. were studied to reveal the genomic interaction between the donor species. High frequencies of aneuploids were observed in the progenies of the amphiploid, indicating its cytological instability. Feulgen staining and Giemsa-C banding showed that only the nucleolar organizing region from chromosome 5D of Ae. tauschii existed in the amphiploid (2n = 28). The nucleolus of S. silvestre was not observed. Endosperm storage protein electrophoresis indicated most gliadin and glutenin genes from both parents were expressed in the endosperm of the amphiploid. When inoculated by wheat stripe rust and powdery mildew isolates,the amphiploid did not express the resistance from its Secale parent,suggesting the presence of disease resistance suppressor(s) in the D genome of Ae. tauschii as well as nucleolar organizer suppressors. This revised version was published online in July 2006 with corrections to the Cover Date.     

27份含D基因组山羊草属种在高产基因座Barc1183的多态性分析

具有D基因组的山羊草属种是小麦重要的野生近缘植物,携带丰富的优异基因,是改良现代小麦的重要遗传资源。SSR标记Barc1183是在川麦42遗传背景中发现的一个来源于人工合成小麦的高产基因座,位于4DL染色体上。本研究,利用基因座Barc1183及其紧密连锁的SSR标记Barc48,以川麦42和川农16为对照,对27份含D基因组的山羊草属材料进行了多态性分析。结果表明,27份山羊草属材料在Barc1183基因座,发现8种等位变异类型,其中6种等位变异类型为不同于对照川麦42和川农16的新类型;而在Barc48基因座,发现5种等位变异类型,这5种等位变异均为不同于对照川麦42和川农16的新等位变异类型。结合Barc1183和Barc48基因座结果分析表明,27份山羊草属材料中均含有不同于川麦42、川农16的等位变异类型,没有一份与川麦42和川农16基因型完全一致的材料。     

First-division restitution in hybrids of Langdon durum disomic substitution lines with rye and Aegilops squarrosa

Durum wheat ‘Langdon’(LDN) caused a high frequency of first‐division restitution (FDR) and partial fertility in hybrids with rye, Secale cereale L., and Aegilops squarrosa L. In order to determine the genetic control of FDR, a complete set of 14 Langdon durum D‐genome disomic substitution lines (LDNDS) was crossed with ‘Gazelle’ rye and one accession (RL5286) of A. squarrosa. The microsporogenesis and fertility of the hybrids were studied. The results showed that most of the hybrids expressed a high frequency of FDR and partial fertility. However, the hybrids of 2D(2A), 4D(4A), 5D(5B) and 6D(6B) crossed with both rye and A. squarrosa, as well as 1D(1A) with A. squarrosa, had either little or no FDR and were completely sterile. These hybrids had different types of first meiotic divisions compared with LDN control hybrids. The hybrids with 2D(2A), 4D(4A) and 6D(6B) had a high frequency of random segregation of chromosomes at the first division. The hybrids with 5D(5B), as expected, showed high homoeologous pairing. The hybrid of 1D(1A) with A. squarrosa had a high frequency of equational division at first division. These results suggest that the reduced or absent FDR in such hybrids might be related to the substitution of chromosomes with an FDR gene and poor compensation ability of the D‐genome chromosomes for their homoeologous A‐ or B‐ genome chromosomes. Cytological analysis suggested that chromosome 4A in LDN most likely carries a gene for high frequency of FDR in hybrids. In addition, some monads were observed at the end of meiosis in the hybrids of 3D(3A) and 6D(6A) crossed with rye. They were formed from FDR cells that failed to divide at second division, suggesting that the LDN 3A and 6A chromosomes might carry genes for normal second division of FDR cells in the rye crosses.