远缘杂交不需幼胚培养的节节麦基因型

六倍体普通小麦(Triticum aestivum L.)是由四倍体小麦(T.turgidum L.)与二倍体节节麦(Aegilops tanschii Coss.)天然杂交然后通过染色体自然加倍形成的异源多倍体.这一起源过程是自然条件下天然发生的,它的发生需要具备一个条件:四倍体小麦与节节麦的天然杂交种子在自然条件(没有幼胚培养等)下能够正常发芽出苗.我们从22份节节麦中发现来自中东的节节麦AS60在不采用幼胚培养等人工辅助条件下,仍然很容易与四倍体小麦和普通小麦产生有生活力的杂种植株.AS60与四倍体小麦的杂交种子有50.0%(反交)及57.1%(正交)的种子,而AS60与六倍体普通小麦的杂交种子则有45.5%不需幼胚培养等措施能够正常发芽、生长.AS60的这一特征正是普通小麦起源过程需要的条件.最后探讨了这一发现对小麦遗传改良和对普通小麦起源演化研究的意义.     

远缘杂交不需幼胚培养的节节麦基因型

六倍体普通小麦（Triticum aestivum L.)是由四倍体小麦（T.turgidum L.)与二倍体节节麦（Aegilops tanschii Coss.)天然杂交然后通过染色体自然加倍形成的异源多倍体。这一起源过程是自然条件下天然发生的,它的发生需要具备一个条件：四倍体小麦与节节麦的天然杂交种子在自然条件（没有幼胚培养等）下能够正常发芽出苗。我们从22份节节麦中发现来自中东的节节麦AS60在不采用幼胚培养等人工辅助条件下,仍然很容易与四体小麦和普通小麦产生有生活力的杂种植株。AS60与四倍体小麦的杂交种子有50．0％（反交）及57．1％（正交）的种子,而AS60与六倍体普通小麦的杂交种子则有45．5％不需幼胚培养等措施能够正常发芽,生长。AS60的这一特征正是普通小麦起源过程需要的条件。最后探讨了这一发现对小麦遗传改良和对普通小麦起源演化研究的意义。     

小麦Glu-B3位点LMW-GS基因的克隆及序列分析

以小麦特殊遗传材料———六倍体普通小麦阿勃二体、1A缺体、1B缺体和1D缺体,四倍体硬粒小麦墨西粒卡以及二倍体节节麦的总基因组DNA为模板,对D Ovidio等曾报道的硬粒小麦Glu-B3位点LMW-GS基因特异引物对P1(5-′tcctgagaagtgcatgacatg-3′)和P2(5-′gtaggcaccaactccggtgc-3′)进行了PCR扩增验证.结果表明,该引物对同样能特异扩增普通小麦Glu-B3位点LMW-GS基因.利用这对引物通过AS-PCR方法克隆得到优良小麦品种小偃6号1B染色体1个LMW-GS基因片段.该基因全长为1 089 bp,包含了完整的编码区和其上游318 bp的胚乳特异表达启动子区.该基因被命名为XY-Glu-B3-LMW2(GenBank登录号为DQ630442).XY-Glu-B3-LMW2的推测蛋白含256个氨基酸(包括N-端20个氨基酸的信号肽),其成熟蛋白有8个保守的Cys残基,均分布在C-末端区.XY-Glu-B3-LMW2是从小偃6号克隆到的第2个LMW-GS基因.     

关于棉属四倍体种起源问题的过氧化物酶同工酶研究

本文采用聚丙烯酰胺凝胶垂直板电泳和等电聚焦技术,对棉属(Gossypium)A基因组2个二倍体种、D基因组10个二倍体野生种和四倍体2(AD)基因组的3个种进行过氧化物酶同工酶酶谱分析。种间酶谱关系符合形态学,细胞学和遗传学的研究结果,但G.gossypioides,G.thurberi和G.trilobum的酶谱与D基因组其他种有较大差异却与A基因组相似。由二倍体种酶液组成的体外人工混合体与自然四倍体的比较分析表明,四倍体棉种G.darwinii,G.barbadense和G.hirsutum是A基因组和D基因组的异质组合,G.raimondii而不是G.thurberi或G.trilobum为四倍体种祖先基因组的最可能的D亚基因组供体。对过氧化物酶同工酶分析为棉属种间亲缘关系和四倍体起源的研究提供生化遗传依据的可行性进行了阐述。     

小麦钙网蛋白基因TaCRT-A多态性及其定位

以苗期抗旱性不同的37份六倍体普通小麦(AABBDD)、3份A基因组材料(AA)和3份四倍体小麦(AABB)为材料,通过直接测序法检测TaCRT-A基因的单核苷酸多态性,分析该基因多态性与小麦苗期抗旱性的关系,并进行遗传定位.结果表明:TaCRT-A基因DNA长度为3887 bp,在总长度为167141 bp的核苷酸序列中共检测到202个核苷酸变异位点,其中包括165个SNP和37个InDel,二者出现的频率分别为1/1013 bp和1/4517 bp.编码区的核苷酸多样性π值小于非编码区,编码区所承受的选择压力较大.43份试材可分为14种单倍型,其中H1、H2和H13分别含有普通小麦二倍体野生近缘种A基因组供体种的1份材料,H6、H7分别包含抗旱性极强的1份材料,H8包含四倍体波斯小麦并同时包含抗旱材料与干旱敏感材料,H11主要包括强抗旱材料与中等抗旱材料;虽然TaCRT受水分胁迫诱导表达,但TaCRT-A基因的结构多态性分析未能揭示其多态性与小麦苗期抗旱性之间的直接关系;利用RIL群体(Opata 85 ×W7984)将该基因定位于3A染色体标记Xmwg30～Xmwg570之间,遗传距离分别为10.5 cM和49.6 cM.     

小麦WOX转录因子基因的全基因组鉴定与分析

小麦是全球主要粮食作物之一.本研究运用生物信息学技术手段对普通小麦(Triticum aestivum L.)的WOX基因进行了全基因组鉴定、系统发育树构建、序列分析.结果显示:小麦基因组一共包含了26个WOX基因,其中在Phytozome数据库中收录有序列信息的有20个,可分为3个亚族,各亚族内的WOX基因具有相似的...     

不同小麦进化材料生育后期光合特性和产量

以二倍体野生一粒小麦(Triticum boeoticum)、栽培一粒小麦(T. monococcum)、节节麦(Aegilops tauschii)和黑麦(Secale cereale)、四倍体野生二粒小麦(T. dicoccoides)、栽培二粒小麦(T. dicoccum)、硬粒小麦(T. durum)、六倍体普通小麦(T. aestivum)‘扬麦9号’和‘扬麦158’及八倍体小黑麦(Triticale)为材料,采用盆栽试验研究了不同小麦进化材料生育后期旗叶光合特性的演变及产量的差异。结果表明,与六倍体普通小麦和八倍体小黑麦相比,二倍体和四倍体材料在开花前具有较高的光合速率(P_n)、气孔导度(G_s)、最大光能转换效率(F_v/F_m)和实际光化学效率(Φ_PSⅡ)。开花以后,二倍体和四倍体材料受非气孔因素的影响,光合能力下降较快;除黑麦外,旗叶光合速率在开花10 d后都低于普通小麦和小黑麦,胞间CO₂浓度(C_i)迅速增加,F_v/F_m、Φ_PSⅡ和叶绿素含量快速下降。二倍体和四倍体材料开花前单株总叶面积和旗叶叶面积较大,花后下降迅速,功能期短;单株穗数也较多,但穗粒数、千粒重、产量和收获指数却显著低于普通小麦。因此,小麦长期进化过程中,普通小麦花后较高的光合能力及较长的光合持续期是提高千粒重,进而提高产量的重要生理基础。     

乌拉尔图小麦的遗传学研究进展

乌拉尔图小麦(T．urartu)是四倍体小麦和普通小麦A基因组的供体,它在普通小麦的发育和进化中起着关键的作用。本文首先介绍了该物种的发现、形态特征和在分类学上的位置,然后从遗传多样性、它与小麦属内其它种的关系、构建基因组文库和1Ay高分子量麦谷蛋白亚基基因的研究等方面综述了乌拉尔图小麦的遗传学研究进展。为了加快普通小麦遗传学、发育和进化、新品种选育等方面的研究,本文建议今后应重点从挖掘优异基因、构建遗传图谱及分离探针和微卫星引物等方面对乌拉尔图小麦作进一步的研究。     

芸薹属蔬菜Chs基因序列多态性

为探讨我国芸薹属蔬菜的起源及遗传多样性,克隆、测序芸薹属不同种的Chs基因序列。A基因组二倍体、A基因组多倍体、B基因组多倍体和C基因组二倍体的Chs基因突变位点数分别为120、172、194和25个,Chs基因多态性表现为:B基因组多倍体A基因组二倍体A基因组多倍体C基因组多倍体。Tajima'D、Fu and Li'D和Fu and Li'F检验表明A基因组二倍体、C基因组二倍体Chs基因是中性进化基因。HKA平衡检验及误配分析表明A基因组多倍体和B基因组多倍体Chs基因进化中存在选择作用。A基因组和B基因组间存在较低的共有差异和较高的共有多态性,C基因组与A、B基因组存在较高的共有差异和较低的共有多态性。系统发育树将芸薹属Chs基因序列分成4个亚支、10个支系。网状分析表明,白菜可能是四倍体A基因组的供体,黑芥可能是四倍体B基因组的供体,甘蓝可能是四倍体C基因组的供体。中国芸薹属蔬菜在Chs基因位点有较高的遗传多态性,不同基因组间分化程度不一样,B基因组分化较大,A和C基因组分化较小。A和B基因组的亲缘关系较A和C基因组以及B和C基因组更为接近。建议根据基因组的不同将中国芸薹蔬菜分成白菜组、芥菜组和甘蓝组,研究结果支持芸薹属进化的禹式三角模型。     

普通小麦7B染色体两类低拷贝专化DNA序列的特性

研究表明, 多倍体小麦基因组中存在一类低拷贝、染色体专化的DNA序列, 其在多倍体形成时常表现出不稳定性.这类序列被认为在异源多倍体的建立和稳定中起着关键作用.为进一步研究这一问题, 对通过染色体显微切割从普通小麦( Triticum aestivum L.)中分离的5个7B染色体专化DNA序列的特性进行了研究.以这些序列为探针对大量的多倍体小麦和它们的二倍体祖先物种进行了Southern杂交分析.结果表明, 这些序列可被分为两种类型:其中的4个序列与所有的多倍体物种均杂交, 但是在二倍体水平上, 它们却只与和多倍体小麦B基因组紧密相关的物种杂交, 这说明这些序列是在二倍体物种分化以后产生的,然后垂直传递给多倍体; 其中的1个序列与所有的二倍体及多倍体物种均杂交, 暗示在多倍体形成后这些序列从A和D基因组中消除了. 用这一序列分别与一个人工合成的六倍体和四倍体小麦进行Southern杂交的结果表明, 序列消除是一个迅速的事件而且很可能与这些序列的甲基化状态有关. 认为这些低拷贝的染色体专化序列对于多倍体形成后部分同源染色体之间的进一步分化起着重要作用.     

Quantitative trait loci mapping reveals pleiotropic effect for grain iron and zinc concentrations in wheat

Malnutrition because of the deficiency of minerals such as iron (Fe) and zinc (Zn) afflicts over 2 billion people worldwide. Wheat is a major staple crop, providing 20% of dietary energy and protein consumption worldwide. Breeding wheat with elevated levels of grain Zn and Fe concentrations (GZn and GFe) represents a significant opportunity to increase the intake of these micronutrients for the resource poor people who depend on it as a major source of dietary energy. Synthetic hexaploid wheats (SHWs) have large genetic variation for GZn and GFe, which can be exploited for developing wheat varieties with higher concentrations of these minerals. The objective of this study was to localise genomic regions associated with GZn and GFe, thousand kernel weight (TKW) and test weight (TW) in a mapping population derived from the cross of Seri M82 and the SHW CWI76364. Major quantitative trait loci (QTL) on chromosome 4BS were detected for GZn and GFe; the QTL explained up to 19.6% of the total phenotypic variation for GZn and showed pleiotropic effects on GFe. This indicates that simultaneous improvement of GZn and GFe is feasible. Three and five QTL for TW and TKW were detected, respectively. One of the QTL for TKW was also located on chromosome 4BS. Positive correlations between plant height and GZn/GFe were observed. The 4BS QTL is of great interest for breeding biofortified wheat by means of marker‐assisted selection.     

小麦花培育种效率与从不同杂种世代取材的关系

通过对小麦花培育种效率与不同杂种世代取材的研究表明,过去小麦花培育种效率低的主要原因是取F1代材料花药培养。通过大量的实验研究认为;用F1代材料进行花药培养育种的效率非常低,特别是在花培苗群体小的情况下,要获得新品种几乎是不可能的,根据实验结果以及理论分析,建议花培育种应结合常规的田间选择,取F2或F3代（特别是F3代）材料是进行花培,育种效果较好。并在此实验结果的指导下,从稍高世代取材,于5－7年的时间内选育出两个通过审定的花培小麦新品种。     

小麦改良的可利用资源：黑麦抗病基因

黑麦(Secale cereale)蕴藏着丰富的抗病基因,是改良小麦抗性的重要资源,黑麦抗病基因的导入一直是小麦育种的重要研究课题。本文综述了黑麦抗病基因的染色体定位、分子标记研究和含黑麦抗病基因的小麦种质资源在我国小麦育种中的应用,对应用中存在的问题进行了分析,并对今后的研究方向进行了展望。     

HMW-GS的SDS-PAGE图谱在小麦品质评价中的应用

采用SDS—PAGE技术对陕西关中地区各时期大面积推广小麦品种、品种资源和新品系的HMW—GS组成进行了分析。在该地区50多年大面积推广的33个品种中,检测出9种HMW亚基(对)及其组成;品种HMW—GS的评分在5～10分之间,平均6．9分;4个时期品种HMW-GS的平均评分有升有降,优质亚基出现的频率普遍偏低;向小麦品种中聚合多种优质HMW—GS将成为陕西关中未来小麦育种的主要目标之一。53种小麦品种资源的亚基或亚基对组合类型比较丰富,具有一批携带优质亚基5 10、1、2*、7 8、14 15或17 18等资源。8个新选品系中,有4个品系携带了多种优质亚基,其中3个品系HMW—GS的评分为10分;Q1043已被审定通过,目前正在陕西关中推广种植。实践证明,采用SDS—PAGE方法对生产上推广品种、品种资源和新选品系的HMW—GS变异研究,有助于在短时间内了解生产上推广小麦品质生产现状、制订育种目标、选配亲本和品系品质性状筛选,是一种非常实用的品质快速检测方法。     

宁夏国外小麦种质资源考察、引进和利用

国外小麦种质资源引进在宁夏小麦引种中发挥着重要的作用。碧玉麦、阿勃、墨卡(卡杰姆F-71)、WC-20(宁春37)、9186(宁冬6号)等国外小麦品种在宁夏生产上直接利用。宁夏春小麦的品质杂交选育始于1953年,利用国外小麦种质资源先后培育出斗地1号、宁春4号等50余个春麦品种。1990年宁夏国外冬麦种质资源的引进带动了宁夏引黄灌区冬麦北移和耕作改制的研究,也引发了宁夏冬麦品种杂交选育的研究。宁夏引黄灌区冬小麦品种的杂交选育的工作始于1991年,经过15年的努力,杂交选育出第一批冬麦品种宁冬10号、宁冬11号,2010年在冬麦生产上取代了明丰5088,不仅实现了宁夏引黄灌区冬小麦品种第3次更新、实现了小麦品种的5次更新,而且使宁夏小麦生产水平跃上新台阶,有力地促进宁夏引黄灌区耕作制度改善和种植业结构的调整。     

Hydroxamic acid levels in Chilean and British wheat seedlings

Fifty-two cultivars of Chilean wheats were screened, using high pressure liquid chromatography, for hydroxamic acid levels at the seedling stage when maximal levels occur. DIMBOA levels ranged from 1.4 to 10.9 mmol/kg fr. wt and DIBOA levels ranged from 0 to 1.1 mmol/kg fr. wt. The family of wheat cultivars leading through breeding to the British cultivar Maris Freeman was examined. While DIMBOA and DIBOA levels in the ancestors ranged from 1.6 to 3.8 mmol/kg fr. wt and 0.16 to 0.34 mmol/kg fr. wt, respectively, DIMBOA and DIBOA levels in Maris Freeman were 2.39 and 0.24 mmol/kg fr. wt, respectively. The results are discussed in terms of the possibility of breeding for aphid resistance by making use of hydroxamic acids.     

Backcross-breeding and doubled-haploid facilitated introgression of stripe rust resistance in bread wheat

Stripe rust caused by the fungus Puccinia striiformis f. sp. tritici (Pst) may decrease wheat yield significantly in severe outbreaks. The most cost-effective and environmentally friendly approach to reduce yield losses due to rust diseases is deployment of effective resistant genes in wheat cultivars. The causal agents evolve and may break existing resistant sources as well. Therefore, long-term conventional breeding strategies and the ongoing evolution of pathogen populations in the region would put the success of breeding programmes at risk so that there is always a need for speeding up the process of germplasm enhancement through production of doubled-haploid breeding materials. In this study, we aimed at introgression of stripe rust resistance trait from three genotypes (Flanders, Martonvasar-17 (MV17) and Bersee) into a widely adapted cultivar “Ghods”. Positively selected F2BC² progenies of three backcrossing schemas, i.e. (i) Flanders/3^*Ghods; (ii) Ghods^*3/MV17; and (iii) Hybride-de-bersee/3^*Ghods, were used to produce three small-size doubled-haploid populations via wheat × Maize pollination methodology. The doubled-haploid populations were examined against two predominantly isolates of P. striiformis f. sp. tritici (Pst) i.e. 6E134A⁺ and 6E2A⁺Yr27⁺ and the screening revealed that 44 and 52 of the progenies are resistant to the above-mentioned isolates, respectively. Field data have shown that the stripe rust resistance doubled-haploid germplasm are comparable to local check cultivars in yield and earliness.     

春小麦花培育种的遗传研究初报

春小麦是我省主要粮食作物,1987年将花药培养的一系列技术应用于育种,先后通过花药培养出一系列品系,已有品系参加省级品种区域性试验。 本文对花培育种的遗传研究表明:对植株诱导率的影响,即不同生态型、基因型F_1花药受不同年份,同时受不同生态区的不同地点,影响出愈率,分化率;供体植株基因型,以花培品系为亲本组合,其平均诱导率均高于不含花培品系的组合,说明小麦再生能力是花培育种的一个特点。不同世代供体基因型,几年来,我们彩用F_1代供体杂种,是提高诱导率和缩短育种年限的有效措施。花粉植株的遗传与变异是育种工作所注目的。     

Synthetic hexaploid wheat enhances variation and adaptive evolution of bread wheat in breeding processes

Synthetic hexaploid wheat (SHW) that combines novel and elite genes from the tetraploid wheat Triticum turgidum L. and wild ancestor Aegilops tauschii Coss., has been used to genetically improve hexaploid common wheat. The abundant genetic diversity in SHW can effectively make breakthroughs in wheat genetic improvement through the inclusion of increased variation. In this paper, we reviewed the current advances in research and utilization of the primary SHW lines and SHW-derived wheat varieties that have enhanced evolution of modern wheat under conditions of natural and artificial selection in southwestern China. Using primary SHW lines, four high-yielding wheat varieties have been developed. In addition, using the SHW-derived varieties as breeding parents, 12 new wheat varieties were also developed. Results of genotype–phenotype and fingerprint analysis showed that the introgressed alleles from SHW lines have contributed a great number of elite characters to the new wheat varieties, and these elite characters include disease resistance, more spikes per plant, more grains per spike, larger grains, and higher grain-yield potential. We found that the primary SHW lines and SHW-derived varieties have identifiable effects to enhance genetic variation and adaptive evolution of modern hexaploid wheat, which significantly increased the grain yields of hexaploid wheat in recent years. These findings have significant implications in the breeding of high-yielding wheat varieties resistant to biotic and abiotic stresses using SHW as genetic resources.     

High levels of genetic diversity throughout the range of the Portuguese wheat landrace 'Barbela'

BACKGROUND AND AIMS: Landrace populations represent an important intra-crop reservoir of biodiversity and source of novel gene alleles for use in breeding programmes. Here the aim was to measure the diversity of a wheat landrace, 'Barbela', from the north of Portugal. METHODS: DNA was extracted from 59 accessions of Barbela collected across its geographical range. Diversity was measured by microsatellite length polymorphisms using 27 primer pairs amplifying 34 polymorphic microsatellite loci. KEY RESULTS: High levels of polymorphism were found, with an average polymorphism information content of 0.52; an average of 4.77 alleles (range 2-11) were present at each locus, and half of these loci showed an additional allele in the reference variety 'Chinese Spring'. CONCLUSIONS: 'Barbela' is maintained from seeds collected by farmers, but it maintains high allelic variation, and no groupings of accessions were detected when analysed by geographical region, farm or climate, indicating that the wheat landrace is a homogeneous entity. The diversity within the farmer-maintained landrace demonstrates the importance of characterization and maintenance of landrace collections before valuable genetic combinations are lost as uniform commercial crops are introduced.