野生棉与陆地棉异源四倍体的合成与性状鉴定

棉属具有丰富的种质资源,将抗病性从野生棉转移到陆地棉中,以此提高陆地棉抗病性是一条理想的育种途经。本研究通过陆地棉和C组野生澳洲棉远缘杂交获得杂种F1,对其进行染色体加倍,将加倍的异源六倍体再与B组野生绿顶棉杂交,产生陆地棉、澳洲棉、绿顶棉的异源四倍体杂种。异源四倍体杂种继承了亲本的部分性状,同时也产生了如蔓生等特异性状;该杂种减数分裂后期染色体不能均等分离,四分体时期有多分体和微核出现;SSR结果发现,该杂种不仅具有三个亲本的特征条带,并且产生了新的重组成分。本研究不仅为该异源四倍体杂种不育提供了直接原因,也为进一步探讨有效的育性恢复方法及棉花新种质创制提供了依据,同时为利用野生棉资源控制棉花黄萎病育种探索培育了中间材料。     

染色体加倍新技术

染色体加倍新技术小麦染色体加倍技术是小麦单倍体育种和远缘杂交的重要技术措施。单倍体植株染色体加倍后可获得纯合二倍体,用作遗传研究或筛选优良品种。远缘杂交F1染色体加倍后,可获得异源双二倍体,创造新物种或用农艺性状好的亲本回交,选育具外缘优良基因的新种……     

陆地棉与雷蒙德氏棉种间杂种后代的胚胎学观察

观察了陆地棉(Gossypium hirsutum L.)与雷蒙德氏棉(G.raimondii U(?)br)种间杂种三倍体F_1、六倍体 F_1和六倍体 F_2、四倍体 F_2以及两个亲本种的早期胚胎发育行为,结果表明,三倍体 F_1有98%以上的胚珠不能形成胚囊,自交和回交完全不育;六倍体 F_1和 F_2及四倍体 F_2均有90%以上的胚珠能形成胚囊,自交和回交部分可育;但其初     

埃塞俄比亚芥与白菜型油菜间六倍体杂种的获得及其生物学特性研究

通过杂交和染色体加倍人工合成了埃塞俄比亚芥×白菜型油菜间的三倍体和六倍体杂种，并对其进行了细胞学鉴定、气孔观察以及一些生理生化特性的分析。在染色体记数、原位杂交和分子标记印证的基础上，比较了两种不同染色体加倍方法的效率；生理生化分析显示，六倍体杂种植株叶片的游离脯氨酸含量、质膜相对透性、Vc含量和叶绿素含量与三倍体杂种植株相比都有明显的差别。     

半配合材料VSG快速稳定棉花远缘杂种后代的研究

用激素处理和染色体加倍的方法获得陆地棉与比克棉、色伯氏棉等野生棉种的远缘杂交后代，结合杂交、回交、聚合杂交的手段，使棉花远缘杂种后代的品质性状得到了显著的提高。为了克服棉属种间杂交后代疯狂分离的难题，使新品系的性状尽快稳定，通过半配合材料VSG作母本与之杂交，得到远缘杂种后代低代材料的单倍体，通过染色体加倍等手段得到了稳定的优质棉新品系。     

亚洲棉、比克氏棉和陆地棉异源四倍体的合成

为了将野生比克氏棉的种子无腺体,而植株上有腺体的珍贵特性转育到栽培棉种上,先用二倍体亚洲棉(A_2A_2)与比克氏棉(G_1G_1)杂交成异源二倍体A_2G_1,将杂种染色体加倍,合成异源四倍体 A_2A_2G_1G_1,再与栽培四倍体陆地棉杂交,组成三交种合成异源四倍体。并对三种杂种的性状遗传学及细胞学进行了分析研究。为培育棉、油、蛋白质三位一体的抗虫新棉种提供了种质。     

由小麦×玉米获得的小麦DH系花粉母细胞减数分裂观察

研究了由小麦×玉米远缘杂交获得的小麦双单倍体DH2代花粉母细胞减数分裂过程。结果表明，大多数双单倍体小麦与异源六倍体普通小麦染色体数目相同，这是染色体经秋水仙素成功加倍的结果。同时在少数细胞中观察到了染色体的“块状移动”，在这些“块”中存在少数“染色体落后”现象，这可能是由于在染色体加倍过程中部分细胞染色体数目发生变异造成的。     

利用异源六倍体(A~rA~rA~nA~nC~nC~n)与甘蓝种间杂交合成甘蓝型油菜的新方法

利用亲本种的遗传变异是改良油菜的重要途径,本研究提出一种利用甘蓝拓宽甘蓝型油菜遗传多样性的新方法。以甘蓝型油菜(AnAnCnCn)品种中双11号为母本,与白菜型油菜(ArAr)品系SWU07杂交,经染色体加倍获得异源六倍体(ArArAnAnCnCn),再与甘蓝(CoCo)杂交,创建出具有亲本种遗传成分的新型甘蓝型油菜(ArAnCnCo)。该六倍体连续3个世代核型稳定,各世代中的自交和自由授粉结实率无显著差异,花粉育性在94.6%～98.8%之间,3个世代自交平均结实率为每角果5.47粒,自由授粉平均结实率为每角果7.93粒;各世代六倍体(ArArAnAnCnCn)与不同类型甘蓝杂交平均结实率分别为每角果0.05、0.04、0.05粒,世代间无显著差异,且六倍体与栽培、野生甘蓝杂交结实性无显著差异,可交配性不受六倍体世代及甘蓝类型的影响。尽管该六倍体与甘蓝可交配性较低,但仍可在田间条件下成功杂交,获得新型甘蓝型油菜(ArAnCnCo),表明以ArArAnAnCnCn六倍体为桥梁与甘蓝杂交,是一种有效导入甘蓝遗传成分、创建新型甘蓝型油菜的新方法。     

介绍两个棉花新种质系

中陆高衣分棉是河北省农科院棉花所于1972年从武安中棉中选出的一株中棉和陆地棉天然杂交不育株,1979年用秋水仙碱进行染色体加倍,获得六倍体杂种,后又与邢台6871杂交,经多年选择,于1984年育成。生育期132天,株高90厘米左右,铃长卵     

陆地棉与雷蒙德氏棉种间杂种后代的形态学及细胞学

本文研究了陆地棉(Gossypium hirsutum L.2n=4x=52,品种为岱字棉15号)×雷蒙德氏棉(G.raimondii Ulbr.,2n=2x=26)种间杂种三倍体 F_1(2n=3x=39)、六倍体 F_1(2n=6x=78)、四倍体F_2(2n=4x=52)和六倍体 F_2(2n=6x=78),一些形态和经济性状的遗传变异及花粉母细胞减数分裂的染色体行为。结果表明,杂种后代表现双亲性状,并进一步证     

二倍体野生棉与四倍体栽培棉基于GISH的遗传关系分析

[目的]研究二倍体野生棉与四倍体栽培棉间的遗传亲缘关系,进一步探索各棉种间的起源与进化.[方法]以5个二倍体基因组的代表种B1(异常棉)、C1(斯特提棉)、E2(索马里棉)、F1(长萼棉)以及G1(比克氏棉)的基因组DNA(gDNA)为探针,以2个四倍体栽培种(陆地棉中棉所16、海岛棉新海7号)有丝分裂中期染色体为靶DNA,进行了基因组原位杂交(Genomic in situ hybridization,GISH)分析.[结果]以B1、E2和F1gDNA为探针时,杂交信号主要分布在2个栽培种较长的13对A亚组染色体上;各产生3对较强的GISH-NOR信号,其中1对分布在较长的A亚组上,2对分布在较短的D亚组上,其GISH-NOR信号强度与分布情况与以D基因组棉种为探针时相似.说明二倍体B、E、F基因组与四倍体棉A亚基因组具有较高的同源性,亲缘关系更近.这一点与它们的地理分布情况相符;而它们基因组中的45S rDNA重复序列与二倍体D基因组的45SrDNA重复序列同源性较高.C1和G1中以gDNA为探针时,杂交信号分布在2个栽培种全部26对染色体上,无法区分开A或D亚组染色体,都有3对较强的GISH-NOR信号.这一现象与D基因组拟似棉(D6) gDNA为探针的GISH相似,表明二倍体C和G基因组与四倍体棉的A和D亚基因组均具有较高的同源性,或者C和G基因组同时含有A基因组(或其他非洲棉基因组)和D基因组成分,进一步证实了其基因组成分的杂合性;而它们基因组中的45S rDNA重复序列同属D基因组类型.[结论]这些发现可为棉花杂交育种和棉属起源与演化研究提供有用信息.     

陆地棉光敏雄性不育基因ys-1的遗传分析与初步定位

【目的】精细定位和克隆陆地棉光敏雄性不育基因。【方法】从陆地棉中040029的航天诱变后代中选育出新型光敏雄性不育系中9106,以中9106与11个陆地棉材料配制杂交组合,初步分析了中9106的杂种优势。以中9106为母本与陆地棉乐土603构建遗传分离群体F1、F2,分析不育性状的遗传特征。利用集团分离分析法筛选简单序列重复(Simple sequence repeat,SSR),并在包含186个单株的中9106×乐土603 F2群体中用上述SSR初步定位不育基因。【结果】中9106为母本×陆地棉乐土603的F1单株育性均表现正常,而F2群体中的可育单株数∶不育单株数符合3∶1的分离比,推测中9106的不育性状受1对隐性核基因控制。利用集团分离分析法从16 544对SSR中筛选到18对与该不育基因连锁的标记。利用中9106×乐土603的F2群体和18对SSR标记,将不育基因定位于D12染色体,位于标记NAU3442与CGR6339之间,遗传距离均为0.2c M,将该不育基因命名为ys-1。【结论】本研究有助于ys-1的精细定位及其克隆。     

Polyploidy and sexual polyploidization in the genus Vaccinium

Genus Vaccinium,consisting of blueberries, cranberries, lingonberries and many related wild species, includes diploid, tetraploid, and hexaploid species. Most evidence indicates that the tetraploid species are autotetraploids, with non-preferential bivalent chromosome pairing. Although homoploid interspecific crosses usually produce numerous fertile hybrids if the parents are from the same section of the genus, inter sectional crosses at the diploid level normally produce no seedlings, weak seedlings, or seedlings that are very low in fertility. There is a strong but not complete triploid block within Vaccinium. Even with insections, tetraploid × diploid (and the reciprocal) crosses normally give only a few tetraploid and a few triploid hybrids. Hexaploid × diploid crosses within sections are very hard to make, and the few hybrids that have been obtained are pentaploid. The frequency of 2n gametes varies,both among genotypes within species and among species. Vaccinium pollen is normally shed in tetrads, and the frequency of large pollen grains shed in dyads can be used to estimate 2n gamete frequency. Cultivated blueberries occur at both the tetraploid and the hexaploid levels, and there are important genetic resources in the diploids. Unreduced gamete production has permitted transfer of genetic material from the diploid to the tetraploid level and from the diploids and tetraploids to the hexaploid level via triploid hybrids. Intersectional crosses can occasionally produce tetraploid Vaccinium hybrids that appear to behave as amphidiploids and have medium to high fertility. CommercialVaccinium cultivars are normally propagated by cuttings. Intersectional hybridization, chromosome doubling, and asexual propagation could permit the production of novel hybrid combinations with value as ornamentals or in fruit production. This revised version was published online in July 2006 with corrections to the Cover Date.     

适于海岛棉指纹图谱构建的SNP核心位点筛选与评价

海岛棉具有纤维品质好、抗病性强等优异性状,不仅为纺织工业提供优质棉纤维原料,也是陆地棉相关性状改良的重要供体材料。然而,与陆地棉相比,开展海岛棉的遗传多样性和基因分型研究相对较少。本研究基于CottonSNP80K芯片对282份不同来源的海岛棉品种/材料进行基因组SNP分型研究,以选择高效鉴别海岛棉材料的核心位点组合。按照检出率大于95%、具多态性、最小等位频率(MAF)大于0.01、杂合率小于0.05、无冗余位点等条件筛选,获得2594个高质量SNP位点。对上述位点设置不同数目梯度筛选,确定最优核心位点数。随着位点个数的增多,位点组合对海岛棉材料的识别率逐渐增加。当位点数为200时,识别率为89%;位点数提高到1500时,识别率可达99%。进一步增加位点数,识别率无显著变化。利用中选的1500个SNP位点检测供试材料,其平均MAF值0.14,平均杂合率0.007,平均多态信息含量0.21。SNP位点的聚丙烯凝胶电泳验证表明,SNP-PCR与芯片分型结果一致性达98.3%。本研究提供了适于海岛棉指纹图谱构建、含1500位点的一套核心SNP位点组合,可用于海岛棉遗传多样性分析和品种身份鉴定。     

陆地棉漆酶基因家族鉴定及在黄萎病菌胁迫下的表达分析

黄萎病是降低棉花产量和品质较为严重的维管束病害。棉花在抵抗病原菌的过程中,抗病基因起着尤为重要的作用。漆酶是一种多功能氧化酶,在植物木质素合成和提高植株抗逆性等方面发挥着重要作用。高质量版本的基因组是提升基因家族分析准确性的必要条件。本研究以目前最新的陆地棉TM-1高质量版本基因组为参考,通过生物信息学分析鉴定了陆地棉基因组中的Laccase(GhirLAC)基因家族,并对其进行了理化性质、基因结构、染色体定位以及在黄萎病胁迫下的表达模式分析。结果表明,陆地棉TM-1基因组中共包含83个GhirLAC家族成员,分布在24条染色体上,所有GhirLAC蛋白均定位在胞外,且具有相同/相似的保守基序。系统发育树分析显示,GhirLAC基因家族成员可分为7个亚组。结合黄萎病胁迫下棉花转录组数据,将GhirLAC基因家族各成员的表达分为3种模式,其中第1类和第2类GhirLAC基因在黄萎病菌胁迫下分别呈现有规律的表达量升高和降低,推测这些基因在棉花抗黄萎病反应中发挥重要功能。荧光定量PCR结果表明,GhirLAC02(GhLAC4)、GhirLAC38(GhLAC11)和GhirLAC20(GhLAC12)3个候选基因均受黄萎病菌诱导表达,其表达趋势与转录组数据相吻合。本研究为以后深入解析棉花GhirLAC基因的抗病功能及分子机制奠定基础。     

Ploidy Manipulation and Introgression of Resistance to Alternaria Helianthi from Wild Hexaploid Helianthus Species to Cultivated Sunflower (H. annuus L.) Aided by Anther Culture

The present investigation discusses the scope for transferring of resistance to leaf spot disease incited by Alternaria helianthi from two hexaploid wild species (H. tuberosus and H. resinosus) to diploid cultivated sunflower. Interspecific hybrids produced between sunflower and these two hexaploid species were partially fertile with tetraploid chromosome status. Backcrosses of these interspecific hybrids with cultivated sunflower resulted in the formation of sterile triploid plants. To overcome the problem of sterility and facilitate backcrosses with cultivated sunflower, anther culture of the tetraploid interspecific hybrids was carried out to bring down their chromosome number to diploid status. Anthers from both interspecific hybrids were cultured on basal Murashige and Skoog media supplemented with varying concentrations of organics and the growth regulators benzyladenine and naphthaleneacetic acid. Anthers of interspecific hybrids involving H. resinosus responded well and regenerated through an embryogenic route at a frequency of 98.7%. But in interspecific hybrids with H. tuberosus, anthers formed callus and subsequently regenerated shoots through an organogenic pathway. DNA ploidy analysis of anther culture plants of interspecific hybrids derived from H. tuberosus crosses was carried out to identify plants with desired diploid status. In vitro screening of parents, interspecific hybrids and anther culture plantlets against A. helianthi showed resistance in 68.5% of the anther culture plants of interspecific hybrids from H. tuberosus and in 24.3% of the plants derived from interspecific hybrids involving H. resinosus.     

In vitro induction of hexaploid plants from triploid hybrids of Pennisetum purpureum and Pennisetum glaucum

This study describes an efficient in vitro method using colchicine-treated triploid seedlings of Napiergrass and Pearl millet hybrids to produce hexaploid hybrids and their subsequent identification with flow cytometry. It also describes chromosome count and stomatal morphology and their use to ploidy analysis. Four-hundred and eighty triploid seeds, representing 12 different hybrids were sterilized and transferred to MS media to induce chromosome doubling. Surviving plants were analysed by flow cytometry. From six triploid (control) and hexaploid plants, the stomata sizes and frequency were analysed. Chromosome count was performed only in the plants identified as hexaploid. Seventeen plants were identified as hexaploid by flow cytometry analysis. Further confirmation of the hexaploid condition was performed with stomatal morphology (stomatal frequency reduction and stomatal length increase) and chromosome count (2n = 6x = 42). Chromosome doubling has numerous applications in Pennisetum breeding. It can be used to restore the fertility of interspecific hybrids and to improve seed size.     

Progenies of an interspecific hybrid betweenArachis hypogaea and A.stenosperma — pest resistance and molecular homogeneity

Summary Interspecific triploid hybrids were obtained betweenArachis hypogaea L. andA. stenosperma Krapov. and W.C. Gregory by adopting hybridization coupled with rescue of the developing hybrid embryos. Two hexaploid hybrid populations were generated from triploids, somatically doubled (SD) and sexually polyploidized (SP) hexaploids. Microscopic screening for the occurrence of 2n gametes in triploid hybrids was useful to predict the production of spontaneous hexaploids. In order to facilitate maximum intergenomic recombination, the hexaploids were allowed to self for several generations (F₄) in the greenhouse. Prolific vegetative growth, pollen stainability, and seed set were observed to decline with each selfed generation. Individuals of the F₃ generation from the two hexaploid populations were evaluated for resistance to nematode (Meloidogyne arenaria Chitwood, race 1) and late leafspotCercosporidium personatum (Berk. & Curt.) Deighton under greenhouse conditions. Both SD and SP populations performed significantly better than their cultivated parent, Sunbelt Runner, and a susceptible cultivar, Florunner. At the DNA level, no significant differences were detected among hybrid individuals using cDNA clones and RAPD primers polymorphic for the two parents. Seven cDNA clones were used to probe DNA from 17 F₂ individuals and two parents and 45 RAPD primers were used to amplify DNA from 21 F₂ and F₃ individuals. No significant differences in banding patterns were observed among hybrid individuals which suggested that little or no detectable intergenomic recombination had occurred.     

Unreduced pollen frequencies versus hybrid production in diploid-tetraploid Vaccinium crosses

Summary Reciprocal crosses were made between highbush Vaccinium corymbosum L. cultivars (4X) and high, medium and low frequency diplandroid pollen producing diploid clones of V. elliotti (Chapm.) and diploid pubescent forms of V. corymbosum. Pollination of 3,342 flowers produced 15 hybrids-11 tetraploids and 4 triploids. All V. elliottii hybrids were tetraploid while each successful diploid-tetraploid V. corymbosum cross produced at least one triploid. The ratio of tetraploid hybrids to 100 pollinations (H: 100P) was considered to be the best criterion for assessing crossability. Vaccinium elliottii produced a total of 8 4X hybrids while 2X V. corymbosum only produced 3. Vaccinium elliottii was more successful as a female parent and diploid V. corymbosum only produced hybrids as male parents. High frequency diplandroid clones showed a lower mean crossability as pollen parents (H: 100P=0.2) than medium frequency diplandroid clones (H: 100P=0.8). As predicted, 0% diplandroid clones wer unsuccessful as pollen parents. Unreduced pollen production was essential for tetraploid hybrid production in 4X×2X crosses. There appeared to be no consistent, inherent pattern between 2n pollen and 2n egg production in a clone nor was a tetraploid genotype effect on crossability consistently observed.Paper No. 10781 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, NC., 27695-7601