小麦与无融合生殖披碱草(Elymus rectisetus)属间杂种F1的形态学和细胞遗传学研究

Elymus rectisetus( Nees in L ehm ) A.L ove et Connor是目前小麦族 ( Triticeae)中发现的唯一的无融合生殖种。本研究以普通小麦 ( Triticum aestivum L.;2 n=6x=4 2 ,AABBDD)为母本 ,以E.rectisetus( 2 n=6x=4 2 ,SSYYWW)为父本进行杂交 ,经过幼胚拯救获得了属间杂种 F1。杂种 F1分蘖力强 ,具有多年生习性 ,其形态特征偏向于父本。杂种 F1高度雄性不育 ,自交不结实。对杂种根尖体细胞的细胞学观察发现 ,杂种 F1体细胞染色体数 2 n=9x=63( SSYYWWABD) ,其中 2 1条来自普通小麦 ,4 2条来自 E.rectisetus。花粉母细胞染色体配对频率为 :2 2 .69 16.15rod 3.0 1ring 0 .83 0 .0 1 。小麦白粉病抗性鉴定结果表明 ,杂种 F1及父本 E.rectisetus表现免疫 ,而母本Fukuhokomugi高度感染白粉病。上述杂种的获得为将 E.rectisetus无融合生殖基因及抗白粉病基因向小麦中转育奠定了基础。     

小麦属2个种间杂种及3个亲本的核型分析

【研究目的】本研究旨在通过细胞学鉴定判断小麦属2个种间杂种的真实性,了解其亲本的染色体组及倍数性;【方法】本试验采用了常规染色体组型分析方法;【结果】分析和报道了小麦属2个种间杂种及其3个亲本的核型,根据核型分析的有关参数,阐明了两个杂种1894×Ps5、新7×Ps5及其亲本新7、1894和Ps5的核型特征,其核型分别为：新7(2n=6x=42)：2M+12sm+28m(2SAT)(2B),1894(2n=6x=42)：2M+20sm+18m(2SAT)+2st(2B),Ps5(2n=4x=28)：2M+12sm(2SAT)+12m+2st(2B),1894×Ps5(2n=5x=35)：2M+19m+12sm+2st(2B),新7×Ps5(2n=5x=35)：1M+21m+13sm(2B);【结论】由此鉴定了2个杂种的真实性--均为真杂种,并确认了亲本新7和1894的第一套和第二套染色体均分别为A组和B组,倍数性均为6x,它们的第三套染色体属什么染色体组有待进一步研究。     

野生二粒小麦与野燕麦杂种核型研究

1989年用野生二粒小麦(Triticum dicoccoides Corn.2n=4x=28)与通北野燕麦(Avenafatua L.2n=6x=42)杂交成功,F_2分离出燕麦型、二粒小麦型、硬粒小麦型、斯卑尔脱型和普通小麦型。斯卑尔脱型F_4中的一个类型,与双亲野生二粒小麦和通北野燕麦的核型进行比较研究。杂种中有一对近端着丝点染色体,5对随体染色体。近端着丝点染色体来源于通北野燕麦,5对随体染体来源于双亲野生二粒小麦和通北野燕麦。证明野生二粒小麦与通北野燕麦杂种斯卑尔脱型是真杂种。     

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     

（普通小麦×沙生冰草）×黑麦三属间的杂种

本文简要地报道了普通小麦×沙生冰草(Agropyron desertorum(Fisch.)Schult.,2n=28,PPPP)杂种F_1(简称CD;2n=5X=35,ABDPP)与两个黑麦(S.cereale L.,2n=14,RR)品种间三属杂种的产生及其形态学、育性和细胞遗传学的研究结果。     

球茎大麦在大麦育种上的应用研究

本文介绍栽培大麦(2x)与球茎大麦(4x)种间杂种的产生及其细胞学鉴定结果。二者杂交成胚率平均可达48.43%,胚培成苗率平均可达25.64%。杂种F1染色体数为21,通过C-带鉴定表明,7条为母本栽培大麦染色体、14条为父本球茎大麦染色体。F1花粉母细胞中染色体构型:单价体4-7个、三价体1-3个,其余为二价体。杂种植株形态为父本球茎     

中国春小麦(6x)×苏联球茎大麦(4x)属间杂交的研究初报

本试验选用抗病性较强的球茎大麦(2n=28)为父本,以普通小麦(2n=42)为母本,进行属间杂交,授粉24小时后,在母本柱头上滴赤霉酸,促使幼胚生长,以中国春单体5B 为母本杂交,获得了少量结实的杂交种子;以中国春为母本的,则结合离体培养杂种幼胚,以获得属间杂种。杂种自花不育,而以中国春单体5B 与之回交,获得三株回交一代杂种(B相似文献   

节节麦与野生燕麦杂交研究

节节麦Aegilops tauschii (Coss·) Sch,2n=2x=14与通北野生燕麦Avena fatua L·2n=6x=42直接杂交成功。F_1有两株,一株优势很强,成穗143个,另一株生长很弱,从苗期开始脚叶就逐渐黄化,成穗14个。经花粉母细胞镜检表明,生长势很强的杂种,是自然加倍的双2倍体,染色体数为2n=8x=56。生长弱的杂种植株,是7倍体,染色体数基本上是2n=7x=49。这2株杂种芒长在护颖和外颖的背上,具有燕麦族芒长在外颖背上的族的特征性状。这2株杂种对国内白粉菌小种均表现免疫。节节麦及其他山羊草种,基本上是不抗白粉病的。7倍体植株的结实率极低。     

一个小麦-大麦2H代换易位系的鉴定与解析

本研究以普通小麦品种‘中国春’染色体组DNA为封阻,用生物素(biotin-16-d UTP)标记的大麦染色体组DNA作为探针,通过基因组原位杂交法解析了来自杂交组合CS×(CS+Betzes 2H)杂种后代X99-13的遗传组成,此材料含有42条染色体,其中1条大麦染色体,2条小麦-大麦易位染色体和39条小麦染色体,鉴定为小麦-大麦代换易位系。以小麦第二部分同源群短臂探针psr131进行RFLP分析,结果表明此代换易位系是涉及小麦染色体2B和大麦染色体2H的代换易位。为进一步选育小麦-大麦2H纯合易位系及利用其上的α-淀粉酶抑制蛋白基因打下了坚实的物质基础。     

节节麦×黑麦的属间杂种的植株形态及细胞学研究

<正> 节节麦(Aegilops squarrosal)2n=14,染色体组型为 DD。黑麦(Secale cere-ale)2n=14,染色体组型为 RR。为了合成包含有 DD 和 RR 染色体组的异源四倍体,我们于1979～1981年进行了节节麦×黑麦的杂交工作,并且获得了杂种 F_1幼苗,本文仅就杂种幼苗的产生及形态学和细胞学研究作一初报:     

Wide hybridization between wheat (Triticum L.) and lymegrass (Leymus Hochst.)

A total of 240 F₁ hybrids was made beween wheat (Triticum aestivum L. em. Thell. (2n = 6x = 42) and T. carthlicum Nevski (2n = 4x = 28)) and perennial lymegrass (North European Leymus arenarius (L.) Hochst. (2n = 8x = 56) and North American L. mollis (Trin.) Pilger (2n = 4x = 28)). The wide crosses yielded embryos in 20% of caryopses and 96% of the embryos developed into normal hybrid plants. The hybrids were vegetatively vigorous, with evidence of the Leymus rhizomatous habit. Those deriving from L. arenarius survived overwintering in Iceland, but the hybrids L. mollis did not, whereas in a milder environment, both showed perenniality. Cytogenetic analysis of root tip cells before the plants were treated with colchicine showed that 21 out of 28 hybrids investigated had chromosome mosaics, with a population of both amphihaploid and amphidiploid cells. This spontaneous doubling of somatic chromosomes occurred in all cross combinations, with the highest average frequency of diploid cells (28%) in T. carthlicum × L. arenarius crosses. A few selfed seeds have been obtained from a T. aestivum × L. arenarius hybrid. All the hybrids were treated twice with colchicine, but the treatment appeared to have little or no effect on the frequency of chromosome doubling in the hybrids deriving from T. aestivum. The frequency of diploid cells, however, increased significantly (e.g. to 80%) in the hybrids deriving from the T. carthlicum parent. Genomic in situ hybridization confirmed the hybridity of the plants and showed that the hybrids were amphiploids containing genomes of both wheat and lymegrass. In situ hybridization using ribosomal DNA probe differentiated chromosomes of L. mollis, L. arenarius from those of wheat. The hybrids are being backcrossed with lymegrass pollen, aiming to domesticate the wild, perennial species. This revised version was published online in July 2006 with corrections to the Cover Date.     

Biotechnological and cytogenetic aspects of producing new wheat genotypes using hybrids

New plant genotypes were produced using barley-wheat hybrids, Hordeum vulgare L. x Triticum aestivum L., and H. geniculatum All. x T. aestivum L. Biotechnological methods were used. Cytogenetic analysis revealed different characters of formation for fertile alloplasmic lines among progenies of H. vulgare x T. aestivum and H. geniculatum x T. aestivum. This revised version was published online in August 2006 with corrections to the Cover Date.     

Production and meiotic pairing of intergeneric hybrids of Triticum × Dasypyrum species

Summary Crossing experiments between Dasypyrum villosum (2 x) and 14 taxa of Triticum sensu lato (seven diploids, five tetraploids and two hexoploids) were performed. Adult hybrids were obtained in all but three of the combinations with diploid species. A haploid plant was obtained from the combination T. aestivum x D. villosum. Cytogenetic data on the meiotic pairing in the intergeneric hybrids revealed that, in general, very little pairing occurred between the V genome of Dasypyrum and the different genomes in Triticum. There may be comparatively large differences in pairing behaviour in hybrids including different parental accessions, which shows that the Triticum as well as the Dasypyrum genotypes may influence the pairing. The combination T. aestivum x D. hordeaceum (4 x) was also produced and from the meiotic pairing in the hybrid it is evident that D. hordeaceum is an autoploid.     

Meiosis and fertility in interspecific hybrids of Nicotiana tabacum L. ×N. glauca Grah. and their derivatives

Nicotiana glauca is of potential interest to breeders as it carries resistance to black root rot of tobacco. Cytological investigations of sexual interspecific hybrids of N. tabacum T′T′TT (2n = 4x = 48) cv. ‘Wiślica’ × N. glauca GG (2n = 2x = 24) were carried out. The analyses of chromosome association at diakinesis and metaphase I in the PMCs of amphihaploid F₁ T′TG (2n = 3x = 36) revealed low variable pairing with 0–5 bivalents. The sterile amphihaploids F₁ were converted into partial female fertile amphidiploids T′T′TTGG by chromosome doubling. Among 36 mature plants obtained, 15 were found to have chromosome numbers (2n = 6x = 72) and were verified as amphidiploids, 9 had (2n = 6x = 70 or 71) chromosomes while the remaining 12 were haploid. True amphidiploids, in spite of quite high chromosome pairing during meiosis, were very different in pollen fertility, ranging from 0% to 85%. Male fertility disturbances did not correlate with the degree of female fertility upon pollination with N. tabacum. Sesquidiploids T′TG (2n = 5x = 60) obtained from backcrossing the amphidiploids to parental tobacco showed more than 22 bivalents, 10–12 univalents and occasional multivalents that indicated the possibility of interchange events between N. tabacum and N. glauca genomes.     

Cytological and Isozyme Evaluation of Tall Fescue × Italian Ryegrass Hybrids

Development of tall fescue (Festuca arundinacea Schreb., 2n = 6x - 42) × Italian rye-grass (Lolium multiflorum Lam., 2n = 2 ×= 14) hybrids would enhance efforts to improve the quality of tall fescue. Two ‘Kentucky 31’ tall fescue בLemtal Italian ryegrass hybrids were obtained via embryo rescue on MS media containing casein hydrolysate, ascorbic acid and sucrose. Chromosome pairing at metaphase I had an average of more than 12 bivalents per cell. Since Festuca-Lolium pairing can account only for seven of the paired chromosomes, intergenomic as well as interspecific chromosome pairing is indicated. There was no cytoplasmic effect on chromosome pairing. To determine if enzymes could be used as genetic markers for distinguishing hybrids from self-contaminants in crosses, zymograms of PGI, 6-PGD, MDH, GOT and ACPH were obtained from parents and hybrids using starch gel etectrophoresis. PGI, 6-PGD and MDH had fewer bands in the diploid ryegrass, as compared with the hexaploid tall fescue and the tetraploid hybrid.     

长穗偃麦草—普通小麦核质杂种的创制及其细胞遗传学分析

以长穗偃麦草(Elytrigia elongata=Agropyron elongatum,2n=70)为母本,普通小麦为父本,进行核置换回交,现已获得第14次回交的核质杂种材料。根据育性和生活力的表现以及细胞遗传学分析,长穗偃麦草-普通小麦核质杂种可分为以下类型:(1)生长正常,育性较好,染色体构型为21″W+1′Eev;(2)生长正常,完全不育或育性很低,染色体构型     

Evidence of functional unreduced gametes in Trifolium repens L.

The current research reports the first evidence of functional 2n gametes in megaspores of Trifolium repens L. Reciprocal backcrossing of a colchicine doubled hexaploid (2n = 6x = 48) T. repens × T. nigrescens (6x H-6909-5) F₁ hybrid to T. repens produced four seeds from 1700 pollinations. The backcross involving 6x H-6909-5 as the female parent and T. repens as the male resulted in only one seed which was, as expected, a pentaploid (2n = 5x = 40) presumably carrying four genomes of T. repens and one genome of T. nigrescens. On the other hand, those backcrosses which utilised T. repens as the female parent and 6x H-6909-5 as the male parent, resulted in 3 viable seeds. These were unexpectedly all heptaploid (2n = 7x = 56) with presumably six genomes of T. repens and one genome of T. nigrescens. The occurrence of heptaploids from a T. repens × 6x H-6909-5 (4x–6x) cross can only be explained by the union of n (= 3x = 24) pollen from 6x H-6909-5 with 2n (= 4x = 32) eggs from T. repens. This revised version was published online in July 2006 with corrections to the Cover Date.     

Introgression of crown rust resistance from Festuca spp. into Lolium multiflorum

Crown rust, Puccinia coronata Corda, causes one of the most damaging foliar diseases in Italian ryegrass, Lolium multiflorum Lam. For introgression of crown rust resistance, highly resistant hybrids of the crosses Festuca arundinacea (2n = 6x = 42) ×L. multiflorum (2n = 4x = 28) and reciprocally, L. multiflorum (2n = 2x = 14) ×Festuca pratensis (2n = 4x = 28) and subsequently resistant recombinant individuals were used as female parents and susceptible cultivars of Italian ryegrass as male parents in three successive backcrosses. The BC₃ plants were selfed and crossed mutually. Uredospores of seven different crown rust isolates collected from plants of L. multiflorum, Lolium perenne, F. pratensis, F. arundinacea and L. multiflorum × F. pratensis hybrids were applied to identify the resistance or susceptibility of the parental species, backcrossed, selfed and intercrossed progenies. The various crown rust populations revealed a species-specific capability to infect plants of the Lolium-Festuca complex corresponding to the host species from which the spores originated. Selected BC⁹ plants, however, were found to be completely resistant to all crown rust populations tested. Successful introgression of the resistance was achieved from F. arundinacea as well as from F. pratensis. The resistance represents a dominant character, apparently based on a strong heterologous incompatibility between host and pathogen. In phenotype, bivalent formation during meiosis and in fertility, the novel germplasms are comparable with the L. multiflorum cultivars.