节节麦×硬粒小麦-簇毛麦双二倍体杂种F_1可孕配子形成途径的细胞学分析

对节节麦×硬粒小麦-簇毛麦双二倍体杂种F_1减数分裂的观察结果表明:该杂种F_1的可孕性是由于杂种F_1产生了大量的(近于)未减数配子的结果。在一些PMC中,单价体中期Ⅰ集结到赤道板上,后期Ⅰ染色单体均等分离产生二分体,二分体发育成有功能的花粉粒。由于染色(单)体的丢失或不分离可产生大量的不完整的重复、缺失未减数配子,完整未减数配子的频率很低。杂种F_1和普通小麦杂交一代及F_2代的细胞学分析结果和F_1配子形成途径分析结果一致。推测从大量的F_2代中可能筛选到自发八倍体(DDAABBVV)。     

节节麦远缘杂种胚的组织培养(简报)

利用活体-离体胚培养和胚愈伤组织诱导、再生植株技术有效地克服了节节麦远缘杂种胚的败育,高效产生了节节麦与硬粒小麦-簇毛麦双倍体、六倍体小黑麦、小麦、大麦间的杂种植株,从而为节节麦种质利用提供了技术方法。     

普通小麦与黑麦属间杂种(F_1)育性特点的研究

34个小麦品种(系)与黑麦进行了杂交,结果表明:亲和性在供试材料间存在明显差异,其中12个小麦品种表现了与中国春相似的亲和性;对34个小麦/黑麦属间杂种(F_1)的回交结实率和开放授粉条件下的自交结实率的统计表明,杂种育性普遍较差,但不同组合间存在明显不同,其回交与自交结实率的变异幅度分别为0—4.50%和0—3.087粒/穗;小麦与黑麦属间杂种(F_1)育性与杂交亲和性间存在明显相关,回交和自交结实率以及能够回交和自交结实组合的出现频率均随亲和性的增加而表现增加的趋势;在小麦品种演化过程中,亲和性与杂种育性均表现降低的趋势;小麦/黑麦属间杂种(F_1)PMC MI染色体配对水平普遍较低,平均交叉结仅为0.359,但组合间存在一定差异,变幅为0—1.3;平均99.936%的杂种(F_1)花粉表现败育,仅有0.064%的杂种(F_1)花粉能被KI—I_2正常染色,杂种(F_1)染色体配对水平与正常染色花粉频率、正常染色花粉频率与自交结实率间存在一定程度的相关性,相关系数分别为0.209和0.205。     

小麦—偃麦草—簇毛麦—黑麦四属杂种的产生及其形态学,细胞学研究

通过胚培养产生了小麦－偃麦草－簇毛麦－黑麦四属杂种。用４个六倍体小偃麦,２个六倍体小簇麦,２个六倍体小黑麦及１个八倍体小偃麦配置了６个四属杂种组合。结果没有出现高度不亲和性。６个组合的杂交结实率分别为６．２％、９．４％、２．４％、９．５％、２５．０％和３．９％;胚培成苗率分别为１２．１％、２０％、３７．４％、４０％、１．１％和７．１％。结果表明,杂交结实率与胚培成苗率间没有相关性。杂种Ｆ１生活力旺盛,形态具有四个属的特征特性。杂种属于自交高不育与低育类型。５个低育类型自交结实率平均约１．２％。四属杂种体细胞染色体数目的变化为３６、３７、３８、３９、４０和４１。其中多数属于具有３８个左右染色体的植株。     

普通小麦与簇毛麦双二倍体的合成,育性及细胞遗传学研究

通过杂种幼胚无性系培养获得大量再生植株F_1,经秋水仙碱处理,合成了普通小麦与簇毛麦属间双二倍体(AABBDDVV)。其形态特征除株高、穗长、小穗数,籽粒大小和育性明显增加,生育期延长外,分别与各自的再生植株F_1相似。双二倍体的体细胞染色体数目变化范围为48—56。花粉母细胞减数分裂中期Ⅰ 2n=28Ⅱ的细胞占56.82％,每个细胞平均有27.10个二价体,1.44个单价体,0.08个三价体,0.03个四价体。经过连续两代单穗单株选择,结实率由15.91％提高到36.52％。     

节节麦×大麦杂种胚再生植株的细胞遗传学研究

以节节麦(2n=14)为母本和大麦(2n=14)进行杂交,两组合平均结实率为31 .11%。对31个幼胚进行愈伤组织诱导培养,其中2个形成全能性愈伤组织进而分化出再生杂种植株。细胞学观察表明,杂种胚再生植株均是染色体加倍的节节麦-大麦双二倍体(2n=28)或染色体再加倍的多倍体。节节麦-大麦双二倍体在减数分裂中期Ⅰ染色体配对平均构型为14.79Ⅰ+1.95Ⅱ+ 4.53Ⅱ′+0.01Ⅲ,表现为自交不育。杂种胚再生植株染色体数目再加倍的多倍体有少数产生了自交种子。 Abstract:Hybridizations between Aegilops tauschii(2n=14)and Hordeum vulgare(2n=14)were made using Ae.tauschii as female.The mean frequency of seed set was 31.11% in two cross combinations,13 hybrid embryos were cultured for inducing callus,of which 2 produced totipotent callus,and plants were regenerated from them.These plants were Ae.tauschii-H.vulgare amphidiploids with doubling chromosome number(2n=28)and octoploids with repeatedly doubling chromosome number(2n=50~56).The Ae.tauschii-H.vulgare amphidiploids were sterile and their average chromosome pairing at MI were 14.79I+1.95II+4.53II′+0.01III.Some octoploid(2n=56)plants produced seeds after selfing.     

普通小麦与粗山羊草属间杂种的染色体构型及其后代的育性特征

利用3个推广品种(莱州953、山农辐63、陕7859)分别与原产地不同的抗白粉病的6份粗山羊草[Aegilops tauschii(Coss.)Schmal.]杂交,得到63个无胚乳的种子,将56枚幼胚接种到N6 0.5mg/L IBA 0.2 mg/L NAA的培养基上进行褓姆培养,得到37个植株。其中莱州953与粗山羊草的杂交结实率和成苗率较高,分别平均为8.58%和4.82%。粗山羊草对白粉病的抗性基因在不同的杂交组合中受到不同程度的改变或抑制。以莱州953为父本,分别与不同组合的杂种F_1回交,大多数组合均得到回交种子,回交结实率平均为1.70%;以莱州953作母本,与莱州953/Y225 F _1回交得到2粒种子,说明普通小麦与粗山羊草的杂种F_1也能产生少量有授精能力的花粉。以山农辐63为父本与山农辐63/Y219 F_1回交亦得到回交种子。通过对普通小麦与粗山羊草6个杂交组合的杂种F_1PMCMI染色体构型的分析,一般多出现14个左右单价体和一定频率的多价体,并观察到可能为A、B组染色体形成的异形二价体;粗山羊草的D组染色体和普通小麦的D组染色体联会正常,可发生自由重组,从而为将粗山羊草的有益基因导入普通小麦提供了细胞学依据。     

节节麦×普通小麦杂种的胚援救和胚愈伤组织再生植株

通过活体-离体胚培养和胚愈伤组织培养有效地克服了节节麦(Aegilops tauschii Cosson.)×小麦(Triticum aestivum L.)杂种幼胚的败育,产生了大量的杂种植株。采用活体-离体胚培技术,节节麦×小麦三个组合杂种幼胚的成苗率为55%,是前人所用传统胚培方法成功率的5—20倍。杂种幼胚在添加有2 mg/L 2,4-D的MS培养基上诱导为愈伤组织,经继代产生全能性愈伤组织,继而分化出再生植株。愈伤组织经继代保存150天仍不丧失分化能力。本文还对两种产生杂种的组织培养方法进行了比较研究。     

利用AABBDDDD八倍体培育小麦-簇毛麦二体附加系的研究

对普通小麦（Triticumaestivum）-节节麦（Aegilopssquarrosa）八倍体（2n=8x=56,AABBDDDD）与硬粒小麦（Triticumdurum）-簇毛麦（Haynaldiavillosa）六倍体（2n=6x＝42,AABBVV）杂交后,将所得七倍体杂种（AABBDDV）进行连续自交,在F4代中利用C-分带鉴定出可能的簇毛麦6V二体附加系95－7和2V二体附加系26－7,其花粉母细胞染色体在减数分裂中期I的配对构型分别为0.14I＋20．42＋1．5和0．10I＋20．07＋1.82;进一步将95－7和26－7的基因组DNA用EcoRI酶切,分别用小麦族第6部分同源群短臂探针Psr113和第2部分同源群长臂探针BCD240进行Southern杂交,结果显示具有簇毛麦的特异杂交带,进一步确证了95－7和26－7分别是普通小麦-簇毛麦6V和2V二体附加系。     

普通小麦×栽培大麦杂种植株及其回交后代的产生和鉴定

以小麦做母本与大麦杂交结实率仅0.77％。本试验通过幼胚培养获得了杂种植株,胚培出苗率37.14％。杂种植株在形态上与小麦相似,完全自交不育。F_1体细胞染色体数目为28,和预期结果一致。花粉母细胞减数分裂中期Ⅰ每个细胞平均二价体数为0.98,单价体数为26.04。用普通小麦做父本与杂种回交,回交结实率为0.26％。     

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.     

普通小麦与粗山羊草正,反交的育性研究

普通小麦与粗山羊草杂交需借助幼胚培养方可获得杂种,取授粉１２～１６天的幼胚进行拯拯救,成苗率较高,效果较好。而不同杂交方式对共杂种成胚率、成苗率及思胚拯救率影响很大。以普通小麦为母本,粗山羊草为父杂交时,１５个杂交组合平均杂种成胚率,成苗率及幼胚拯率分别为５．３５％和５８．７３％,而在１２个反交组合中,其平均成胚率,成苗率及幼胚拯救率分别为９８．８８％、１７．１０％和２４．４４％。由此可见,普通小     

节节麦-簇毛麦属间杂种的形态学和细胞遗传学研究

通过远缘杂交,结合杂种幼胚离体培养,获得了节节麦（Aegilops tauschii,2n=14,DD）和簇毛麦（Dasypyrum villosum,2n=14,VV）的属间杂种F1。对杂种F1花粉母细胞减数(PMC)分裂中期Ⅰ (MⅠ)染色体配对行为进行观察发现,“节节麦×簇毛麦”杂种F1平均每PMC有1.25个棒状二价体, 染色体的平均构型为2n=14=11.49Ⅰ+1.25Ⅱ (Xta=1.25), 大部分被观察的细胞出现1～5个二价体, 表明节节麦D染色体与簇毛麦V染色体间具有相对较高的部分同源配对, D和V染色体之间存在一定的部分同源性。F1植株高度自交不育,经染色体加倍处理后能够自交结实。Abstract: ‘Aegilops tauschii×Dasypyrum villosum’ F1 hybrids were obtained by the combination of hybridization and embryo culture in vitro. Chromosome pairing behavior in meiosis of the hybrid F1 was carried out. Results showed that in an average , 1.25 rod bivalents were observed in one PMC, meiotic configuration was 2n=14=11.49Ⅰ+1.25Ⅱ(Xta=1.25) and most of PMCs possessed 1～5(rod) bivalens, indicating that the relatively high homeology was detected between the D genome of Ae.tauschii and the V genome of D.villosum. The morphological differences between F1 hybrids and their parents were significant. F1 plants were highly self-sterile, but partially self-fertile after treated by chromosome doubling technique.     

Meiotic restriction in emmer wheat is controlled by one or more nuclear genes that continue to function in derived lines

Highly fertile F₁ hybrids were made between Triticum turgidum L. ssp. turgidum (2n = 28, AABB) and Aegilops tauschii Coss. (2n = 14, DD) without embryo rescue and hormone treatment. The F₁ plants had an average seed set of 25%. Approximately 96% of the F₂ seeds were able to germinate normally and about 67% of the F₂ plants were spontaneous amphidiploid (2n = 42, AABBDD). Cytological analysis of male gametogenesis of the F₁ plants showed that meiotic restitution is responsible for the high fertility. A mitosis-like meiosis led to meiotic restitution at either of the two meiotic divisions resulting in unreduced gametes. Test crosses of the T. t. turgidum–Ae. tauschii amphidiploid with Ae. variabilis and rye suggested that the mitosis-like meiosis is controlled by one or more nuclear genes that continue to function in derived lines. This discovery indicates a potential application of such genes in producing double haploids.     

中国特有小麦中杂种黄化基因Chl和提型胞质育性恢复基因的分布研究

本研究以Ｔ型不育系ＱＡ１１０４（具有杂种黄化基因Ｃｈ２）和Ｋｈａｐｌｉ（具有杂种黄化基因Ｃｈ１）为测验种,对中国特有小麦等六倍体小麦类型和一些四倍体小麦类型中的Ｔ型胞质育性恢复基因和杂种黄化Ｃｈ１基因的分布进行了研究。结果表明：中国白麦子类型、西藏半野生小麦、云南铁壳麦、圆锥小麦（矮兰麦）一节节麦人工合成双二倍体以及中国圆锥小麦等类型中未发现Ｔ型育性恢复基因和杂种黄化基因Ｃｈ１;在斯卑尔脱小麦杜哈米林类型和野生二粒小麦中发现有Ｔ型育性恢复基因的存在,但是不存在杂种黄化基因Ｃｈ１。在新疆稻麦和中国波兰小麦中未发现有Ｔ型胞质育性恢复基因的存在。但在新疆稻麦中普遍含有杂种黄化基因Ｃｈ１,在波兰小麦中一些居群有Ｃｈ１基因、一些居群无。这暗示：新疆稻麦可能来源于含有Ｃｈ１基因的波兰小麦类型,而且可能是起源于波兰小麦与节节麦的天然杂交并经过双二倍体化途径而形成的。     

鹅观草属——人工合成双二倍体(2n=10x=70)的细胞学及育性的研究

本文对缘毛鹅观草(Roegneria pendulina)、鹅观草(R.tsukushiensis var.transiens)及其人工合成杂种F_1、双二倍体进行了细胞学,育性等的分析和研究。结果表明双亲的减数分裂,花粉育性和结实性均正常,杂种F_1的减数分裂不规则且完全不育;当代双二倍体的染色体数目为70,其减数分裂构型为:6.04 Ⅰ+26.21 Ⅱ+1.52 Ⅲ+1.59 Ⅳ+0.02 Ⅴ:第二代双二倍体的染色体数目为70,个别植株为69,减数分裂构型分别为:4.16 Ⅰ+27.33 Ⅱ+0.50 Ⅲ+2.16 Ⅳ和4.79 Ⅰ26.26 Ⅱ+1.13 Ⅲ+2.13 Ⅳ。与期望染色体配对模式相比,双二倍体中二价体出现的频率有明显增大的趋势。在减数分裂AⅠ和AⅡ分别观察到数目不定的落后单价体,大部份的四分体中出现了微核。双二倍体的育性得到了很大程度的恢复,其花粉可染色性及结实率分别为54.4％和64.0％。     

Cytological Studies on F1 Hybrids Between Hexaploid Aegilops and Triticum aestivum

Morphologcal and cytological studies of hybrids between hexaploid Aegilops crassa Boiss. (2n = 6x = 42, DDD2 D2Mcr Mcr), Ae. vavilovii (Zhuk.) Chen. (2n = 6x = 42, DDMcr McrSp Sp) and Triticum aestivum L. (2n= 6x = 42, AABBDD) were carried out. The results showed that most of the F1 hybrids morphologically resembled their Aegilops parental species. Four Fl hybrids of Ae. vavilovii × T. aestivum and one of Ae. crassa × T. aestivum produced seeds containing few endosperms. The percentage of seed obtained ranged from 0.1% to 6.5 %. These seeds were not vigorous and only a few of them germinated. A large number of univalents appeared at meiosis MI. The frequencies of bivalents were lower than those being theoriticaly estimated. These results indicated that the D genomes in Ae. Crassa and Ae. vavilovii may have been substantially modified. Trivalents were observed in all Fl hybrids. Quadrivalents and pentavalents were also observed in some PMCs during meiosis. The chiasmata frequencies in hybrids using Aegilops species as maternal parents were higher than those in their reciprocal ones. Chromosome segrigations were abnormal at A Ⅰ and A Ⅱ . Polyads and micronuclei appeared frequently at telophase tetrad stage. A plant with 21 chromosomes was obtained in Ae. vavilovii × Jimai 30, although the reason was not yet clear.     

Reproduction and cytogenetic characterization of interspecific hybrids derived from Cucumis hystrix Chakr. x Cucumis sativus L

Interspecific hybrids between Cucumis hystrix Chakr. (2n = 2 x = 24) and Cucumis sativus L. (2n = 2 x = 14) were produced by means of F(1) (2n = 19) embryo rescue and subsequent chromosome doubling. The hybridity was confirmed by genomic in situ hybridization (GISH) and chromosome analysis. The amphidiploid (2n = 38) was self-pollinated and backcrossed to cucumber resulting in lines with improved crossability to C. sativus. Examination of shape, stainability, and germination rate of pollen grains and yield as a function of mature fruit set per ten pollinated flowers indicated a tendency for increased fertility in BC(1)S(1) progeny when compared to F(1) and amphidiploid offspring. Cytogenetic characterization of F(1) and amphidiploid progeny was performed. Generally normal meioses produced viable pollen grains, and fertilization resulted in partial fertility restoration in amphidiploid progeny. Chromosome anomalies such as "frying-pan trivalent", chromosome lagging and spindle mis-orientation were also observed. In most of the PMCs of the F(1) diploid hybrid progeny, 19 univalents were observed at diakinesis and MI. In the amphidiploid, more than 90% of the configurations at MI consisted of the predicted 19 bivalents and less than 5% contained multivalents [trivalents (2.3%) + quadrivalents (0.3%)], suggesting the presence of preferential pairing, and a distinctive parental genome as well. The chiasmata observed between homoeologous chromosomes further demonstrated the introgression of the C. hystrix genome into that of C. sativus.     

普通小麦与祖山羊草杂种后代的细胞遗传学初步研究

粗山羊草(Aegilops tauschii(Coss.)Schmal.,DD,2n=14)是普通小麦(Triticumaestivum L.,AABBDD,2n=42)D染色体组的供体。粗山羊草中含有丰富的抗病,抗虫,抗逆,优质等优异基因,因此粗山羊草是改良普通小麦的宝贵遗传资源。但有关普通小麦与粗山羊草杂交的研究报道较少。本文试图通过对普通小麦与粗山羊草杂种后代的细胞遗传学和染色体分离规律的研究,探讨转移粗山羊草优异基因的方法和途径。