Chromosome comparison among five species of platyrrhini (Alouatta caraya,Aotus azarae,Callithrix jacchus,Cebus apella,andSaimiri sciureus)

Karyotypes of 82 individuals from five Platyrrhini species (Alouatta caraya, Aotus azarae, Callithrix jacchus, Cebus apella, andSaimiri sciureus) were studied and compared using a G-banding technique. Cytogenetic analysis showed full chromosome or full arm homologies among these geographically neighbouring species. A small number of chromosomal rearrangements (inversions, deletions, and translocations) could be detected among these taxa. These five species are closely related in chromosomal evolution. An interesting correspondance was found betweenCebus apella chromosomes and those of the other four species.Alouatta caraya andCebus apella are the closest species.Callithrix jacchus andAotus azarae would have the most separated karyotypes.     

Assessment of the degree and the type of restriction fragment length polymorphism in barley (Hordeum vulgare)

Summary In order to determine the extent of polymorphism in barley (Hordeum vulgare), DNA from 48 varieties was analyzed with 23 genomic, single-copy probes, distributed across all seven chromosomes. Upon hybridization to wheat-barley addition lines, the probes showed different degrees of homology compared to the wheat genome. Polymorphisms were detected in the barley genome at a frequency of 43% after digestion with EcoRI, BamHI, and HindIII. Subgroups of spring and winter barley and of two- and six-rowed types showed less diversity which, in most cases, was due to shifts in allelic frequencies. One probe (MWG1H504) hybridized to an EcoRI restriction fragment exclusively observed in winter barley. A comparison of six different restriction enzymes revealed clear differences with regard to their efficiency in detecting polymorphisms. The respective frequencies were between 13% (HindIII) and 37% (EcoRV). A significant correlation between the efficiency of a restriction enzyme and the mean fragment size detected by the different probes identified insertion/deletion events as the major factor causing polymorphism in barley.     

A novel intergeneric hybrid in the Triticeae: Triticum aestivum x Psathyrost achys juncea

Summary Two hybrid embryos of intergeneric origin between Triticum aestivum cv Fukuho (2n=6x=42, AABBDD) and Psathyrostachys juncea (2n=2x=14, NN) were successfully rescued. One hybrid plant had the expected chromosome number of 28 (ABDN), whereas the second plant had 35 chromosomes. The average meiotic chromosome pairing in the 35-chromosome hybrid was 21.87 univalents + 6.38 bivalents + 0.11 trivalents + 0.009 quadrivalents, which indicates that two copies of the N genome were present. Chromosome pairing in the 28-chromosome hybrid was low (1.35 bivalents), and pointed out the lack of homology between the wheat genomes and the P. juncea genome. These new hybrids showed some necrosis and chlorosis, which caused severe floral abortion in the plant that had 35 chromosomes. These problems became gradually less severe after 18 months.Contrib. no. 372     

Multidisciplinary approach to genome analysis in the diploid species,Thinopyrum bessarabicum and Th. elongatum (Lophopyrum elongatum), of the Triticeae

Summary The J and E genome species of the Triticeae are invaluable sources of salt tolerance. The evidence concerning the phyletic relatedness of the J genome of diploid Thinopyrum bessarabicum and the E genome of diploid Th. elongatum (=Lophopyrum elongatum) is discussed. Low level of chromosome pairing between J and E at different ploidy levels, suppression of J-E pairing by the Ph1 pairing regulator that inhibits homoeologous pairing, complete sterility of the diploid hybrids (JE), karyotypic divergence of the two genomes, differences in total content and distribution of heterochromatin along their chromosomes, and marked differences in gliadin proteins, isozymes, 5S DNA, and rDNA indicate that J and E are distinct genomes. Well-defined biochemical markers have been identified in the two genomes and may be useful in plant breeding. The level of distinction between J and E is comparable to that among the universally accepted homoeologous genomes A, B, and D of wheat. Therefore, the J and E genomes are homoeologous and not homologous, although some workers continue to call them homologous. The previous workers' data on chromosome pairing in diploid hybrids and/ or karyotypic differences in the conventionally stained chromosomes do not provide sufficient evidence for the proposed merger of J and E genomes (and, hence, of the genera Thinopyrum and Lophopyrum) specifically and for establishing genome relationships generally. Extra precautions should be exercised before changing the designation of an established genome and before merging two genera. A uniform, standardized system of genomic nomenclature for the entire Triticeae is proposed, which should benefit cytogeneticists, plant breeders, taxonomists, and evolutionists.Cooperative investigations of the USDA-Agricultural Research Service and the Utah Agricultural Experiment Station, Logan, UT 84322, USA. Approved as Journal Paper no. 3832     

两种苦豆子染色体的初步观察

苦豆子和准噶尔苦豆子均属豆科,槐属,弯果系,为野生灌木。可作绿肥,能固沙,根可作药用,是治疗痢疾、咳嗽等疾病的植物药新资源,在我国西北各省区均有大量分布。     

中国蔷薇属6个种的染色体研究

本文对原产中国的蔷薇属6种植物(Rosa spp.)进行了染色体观察,其中1种(巨花蔷薇(Rosa gigantea(Crep)Rehd.et Wils.))为国家重点保护植物,2种(疏花蔷薇(R.laxa Retz.)、宽刺蔷薇(R.platyacantha Shrenk))为国内首次报道。观察结果如下:染色体数目为2n=2x=14或2n=3x=21,均为小型染色体(2.24—2.78μm),其中大部分长度接近,染色体长度之比小于2;属对称核型。文中讨论了一些种(变种)的染色体数目及核型。     

节节麦和硬粒小麦-簇毛麦双二倍体间杂种的产生及其细胞遗传学研究

通过胚培养产生了节节麦和硬粒小麦-簇毛麦双二倍体间的杂种。结果表明节节麦和硬粒小麦-簇毛麦双二倍体杂交以节节麦作母本较易结实,3个组合的结实率分别为59.18%、67.72%和60.22%,胚培成苗率分别为39.13%、38.10%和50%。杂种F_1生活力旺盛,形态像父本硬粒小麦-簇毛麦双二倍体。杂种自交可孕,3个组合自交结实率平均为7.63%。杂种F_1(ABVD)的减数分裂平均构型为25.36个单价体,1.21个二价体和0.06个三价体,平均每个细胞交叉结频率为1.38,高于“中国春”单倍体的配对频率,推测V组和A、B、D组染色体间有部分同源关系。节节麦和硬粒小麦-簇毛麦双二倍体杂交可能是产生八倍体(AABBDDVV)的又一途径。     

phlb基因诱导小麦ABD染色体组部分同源染色体配对的研究

通过花药培养首次获得了“中国春”phlb突变体单倍体,同时也获得了“中国春”单倍体。对其细胞学观察表明,前者花粉母细胞减数分裂中期Ⅰ每个细胞染色体交叉为5.08个,后者为1.30个。证明了phlb基因在单倍体状态下具有强的诱导ABD染色体组部分同源染色体间的配对作用。     

一个小麦—黑麦染色体代换的细胞学鉴定

对从六倍体小黑麦与普通小麦的杂种后代中获得的矮秆抗病选系84056-1-36-1进行体细胞C-分带鉴定,结果表明,它的21对染色体中,有1对短臂带型与1R相似的黑麦染色体代换了小麦的1D。观察“中国春”双端二体1A、1B与该选系杂种F_1的花粉母细胞染色体配对,发现分别有82.56%和65.71%的细胞出现异型三价体,所有细胞至少有两个形态不同的单价体;而在“中国春”端二体IDL与84056-1-36-1的杂种中,端体不配对的花粉母细胞占100%,经C-分带后,另外1条单价体显示明显的端带。从上述这些结果推断84056-1-36-1为1R(1D)代换系。     

Genomic relationships among diploid wild perennial species of the genus Glycine Willd. subgenus Glycine revealed by crossability,meiotic chromosome pairing and seed protein electrophoresis

Summary The nomenclature of species beased on classical taxonomy can be verified from cytogenetic, biochemical and molecular studies. The objective of the study presented here was to provide further information on genomic affinities among species of the genus Glycine Willd. based on crossability, meiotic chromosome pairing of F₁ hybrids and seed-protein profiles. Meiotic chromosome pairing data revealed no genomic similarity between G. microphylla (BB) and G. falcata (FF), nor between G. tomentella (2n = 38; EE) and G. microphylla (BB). Despite morphological similarity between G. cyrtoloba (CC) and G. curvata no F₁ hybrid was obtained, although 748 flowers were pollinated. The seed-protein banding patterns showed G. latrobeana to be closer to the A-genome species than to others. Based on these results we assign genome symbol A₃A₃ to G. latrobeana. Likewise, G. curvata was allotted the designation C₁C₁ because the seed-protein banding patterns of G. curvata and G. cyrtoloba are similar. The genome designations of Glycine species based on cytogenetic investigations may be further extended by results obtained from biochemical and molecular approaches.Research supported in part by the Illinois Agricultural Experiment Station and US Department of Agriculture Competitive Research Grant 88-37231-4100