摘要:

A tertiary trisomic of the tomato, which originated as a spontaneous aberrant aneuploid in the progeny of triplo-5, was determined through pachytene analysis to involve the extra chromosome 5L·7S with breakpoints in either the centromere or proximal heterochromatin. The genes af and tf on 5S gave normal segregation with 2n+5L·7S while var on 7S gave trisomic segregation. Genetic confirmation for 5L was not obtained.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796749

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

After backcrossing with maize, a 46-chromosome intergeneric hybrid betweenZea maysL. andTripsacum dactyloides(L.) L. (2n=72) gave rise to cytologically and morphologically variable populations. Twenty-chromosome offspring derived from different cytological pathways from the F1to recovered maize were studied. NoTripsacumchromosome insertions to maize were identified by studying pachytene configurations. Ten of 20 lines had significantly reduced chiasmata frequences as compared to F1hybrids between standard maize genetic stocks and the recovered maize lines. Six linkage groups on chromosomes 2, 4, 7 and 9 were analyzed. Significant decreases in crossing over were observed for the 1g1—- g12linkage group of chromosome 2 and for the su1—- g13group of chromosome 4. The linkage groups g12—- V4of chromosome 2 and o2—- g11of chromosome 7 showed increasing crossing over trends for all recovered maize lines. Few significant increases or reductions were observed for the yg2—- g115and g115—- bm4groups of chromosome 9. All morphologically tripsacoid lines had significantly altered crossing over frequencies from check plants while only eight of the 14 nontripsacoid lines were significant.Tripsacumintrogression is believed to be the cause of decreased chiasmata frequencies and linkage relationships.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796750

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Differentiating metaxylem cell lines reveal an increase in nucleolar volume with a parallel increase in r-RNA content of cells. Nucleoli of rapidly elongating metaxylem cells contain feulgen positive material with a concurrent upsurge in endogenous r-RNA level of cells. In late stages of metaxylem differentiation, an extrusion of nucleolus is observed which is followed by an extensive autolysis of protoplast.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796751

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

The all-female Tettigoniid grasshopperXiphidiopsis litais a diploid species with 2n=26 (XX+12 pairs of autosomes). There is one pair of huge metacentric chromosomes which, by comparison with the karyotype of the bisexualPhisissp., are interpreted as autosomes. There is no indication of structural heterozygosity in the karyotype ofX. lita, and hence no evidence for a hybrid origin of the species. The cytological mechanism of parthenogenesis (i.e. the nature of the maturation divisions in the oocyte) is still unknown.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796752

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Karyotype analyses of the native IraqAegilopsspecies were based on mitotic metaphase cells with well spread chromosomes. The three species have two satellited pairs of chromosomes. Besides,Ae. umbellulatahas one metacentric chromosome pair, two subtacentric pairs, and two subtelocentric pairs.Aegilops speltoideshas, in addition to the satellited chromosomes, three metacentric chromosome pairs, and two submetacentric pairs.Aegilops ligusticahas five metacentric chromosome pairs and two satellited pairs.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796753

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Meiotic studies ofHyparrhenia hirta(L.) Stapf revealed aneuploidy with 2n=36, 54 and 56 chromosomes. The plants with 2n=54 chromosomes had much wider distribution than the other two types of plants. Diakinesis and metaphase I revealed a very high multivalent ratio. It is argued that the formation of multivalents is mainly due to the loss of chromosomes carrying genes which suppress multivalent formation. Furthermore, scarcity of autopolyploidy in nature is attributed to the gene-controlled pairing of chromosomes blurring the difference between auto-, allo-, and segmental allopolyploidy. Some of the multivalent associations might be partly due to translocation and other kinds of chromosomal rearrangements.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796754

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

The author present a study of the distribution, frequency, and behaviour of the supernumerary chromosomes found in populations of 12 species of the genusSolidagoand one closely related taxon,Euthamia graminifolia, all of the family Compositae, tribe Asterieae.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796755

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

In this research we observed the distribution of potassium pyroantimonate (KPA) precipitable inorganic cations in the cells ofNicotiana glutinosaL. leaves either healthy or mechanically infected with tobacco mosaic virus (TMV).

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796756

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Five species of Cricetinae were investigated with regard to chromosome banding pattern homology. The strikingly coincident G-banding patterns present inCricetus cricetusandCricetulus griseuscould not be found in the other species. OnlyPhodopus sungorusshows a still considerable number of homologous segments of chromosomes. The C-banded karyotypes reveal fundamental differences in amount and distribution of heterochromatin. The highest amounts of heterochromatin are found inCricetus cricetusandMesocricetus auratus, the lowest amount is shown byMystromys albicaudatus.The karyotype ofCricetus cricetusis characterized by large blocks of centromeric heterochromatin, that ofMesocricetus auratusby totally heterochromatic short arms of many chromosomes.Cricetulus griseusandPhodopus sungoruspossess several pairs of chromosomes without distinct centromeric heterochromatin. Each autosome ofMystromys albicaudatusreveals a small amount of heterochromatin in the centromeric region; two pairs of chromosomes possess heterochromatic short arms.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796757

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor

摘要:

Primary trisomics ofTrigonella corniculatawere isolated from spontaneous autotriploids. They differed from the diploids, as well as from one another, in morphological characteristics. Individual trisomics were confirmed from a study of their somatic chromosomes. They were designated on the basis of the most conspicuous morphological features as ‘Purple midrib’, ‘Thick leaf’, ‘Deep curvature’, ‘Condensed’ ‘Notched’, ‘Tiny’, ‘Dark green’ and ‘Pseudonormal’ which had respectively from the first to the eight chromosome extra to the normal somatic complement in the order of decreasing length. One of the autotriploids was picked out from an irradiated population and, therefore, the morphological variation observed in the trisomics is the result of both trisomy and heterozygosity.

ISSN:0008-7114    

DOI:10.1080/00087114.1978.10796758

出版商:Taylor & Francis    

年代:1978

数据来源: Taylor