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1.
Giemsa N-banding pattern in cabbage and Chinese kale 总被引：1，自引：0，他引：1
Summary In cabbage (Brassica oleracea var. capitata) and Chinese kale (B. oleracea alboglabra) four types of N-bands can be distinguished: pericentromeric, telomeric (terminal), intercalary and satellite bands. Typical NOR bands were not observed. The pericentromeric bands appear at the pericentric regions, possibly even at the centromeres of all chromosomes. Telomeric bands are observed on the short arms of chromosomes 1,5 and 6 in cabbage and chromosomes 1 and 5 in Chinese kale. Intercalary bands stained weakly in the long arms of chromosome 3 in cabbage and chromosome 2 in Chinese kale. Satellite bands cover the entire satellites in both Brassica species. The N-banding pattern is very similar in appearance to the C-banding pattern in both species and much more convenient to apply. 相似文献
2.
Summary The meiotic pairing behaviour at metaphase I of a Triticum aestivum×Triticum monococcum hybrid has been studied by means of the C-banding technique to ascertain the homology between the chromosomes in the A genome of the two species. The technique allowed the A and B genome chromosomes and the 2D, 3D and 5D chromosomes to be identified. Differences in the level of chromosome pairing in the A genome were noted. The T. monococcum 4A chromosome did not pair with any of the T. aestivum chromosomes in any of the metaphase I cells analysed. Two reciprocal translocations between the 2B and 2D chromosomes on one side and the 2A and 3D on the other side have been identified. The usefulness of the C-banding technique in the study of chromosome homology among species related to wheat is discussed. 相似文献
3.
Karyotype of Canada wildrye (Elymus canadenisis L.) was described using giemsa C-banding techniques. Most of the chromosomes showed dome banding pattern polymorphism. Small to large terminal and centormere bands were observed in most of the chromosomes. A faint satellite was observed in one chromosome. Tow chromosomes had a large interstitial band near the centromeres in the long arms. The Giemsa C-banding pattern of E. Canadensis is compared to that of Pseudoroegneria spicata and Critesion boddanii to illustrate species relationship. 相似文献
4.
Summary The meiotic behaviour of a hybrid between Triticum aestivum and the amphiploid Hordeum chilense x T. turgidum conv. durum, was studied using a C-banding staining method. This hybrid has the genome formula of AA BB D Hch with 2n=6x=42 chromosomes. The durum wheat chromosomes (genomes A and B) were easily recognized, whereas the D and Hch chromosomes were recognized as a whole. Meiotic pairing was homologous, as expected (14 bivalents from A and B genomes +14 univalents from D and Hch genomes). However, some pollen mother cells at metaphase-I presented pseudobivalents that could have been caused by either homoeologous or autosyndetic pairing amongst D and Hch chromosomes. 相似文献
5.
Prem P. Jauhar 《Euphytica》2006,148(3):341-344
Summary Durum or macaroni wheat (Triticum turgidum L., 2n = 4x = 28; AABB genomes) arose as a natural hybrid between two wild species, Aegilops speltoides Tausch (2n = 2x = 14; BB genome) and Triticum urartu Tumanian (2n = 2x = 14; AA genome). The two progenitors hybridized in nature about half a million years ago and gave rise to tetraploid wheat, presumably in one step as a result of functioning of unreduced gametes in their hybrid BA (amphihaploid). It is easily possible to go back on the evolutionary scale and obtain durum haploids BA, and then regenerate tetraploid durum plants from them. Interestingly, such a reversion to haploidy does occur in nature as well, although at a very low frequency. This article reports on the occurrence of two spontaneous durum haploids and describes their chromosomal characteristics. The haploids (euhaploids, to be precise) had 14 somatic chromosomes, which, on fluorescent genomic in situ hybridization (fl-GISH), could be distinguished as 7 A-genome and 7 B-genome chromosomes. At meiosis, only 2.3 and 2.7% of the chromosomes paired in the two haploids, because of the presence of the homoeologous pairing-suppressor gene, Ph1. The Ph1-induced lack of pairing is a prerequisite for chromosome doubling through the formation of unreduced gametes that give rise to tetraploid durum wheats.Mention of trade names or commercial products in this publication is solely to provide specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. 相似文献
6.
Fluorochrome staining with chromomycin A3(CMA) was used to characterize and compare the CMA banding patterns of chromosomes in 17 accessions of mandarins (Citrus spp.). All accessions had 2n = 18 chromosomes. These chromosomes were classified into six types based on the number and position
of CMA positive bands; A: two telomeric and one proximal band, B: one telomeric and one proximal band, C: two telomeric bands,
D: one telomeric band, E: without bands, F: one proximal band. Each accession possessed two to five types of chromosomes,
and showed unique CMA banding patterns. Type D and E chromosomes were predominant in all accessions. Their numbers were generally
higher in Chinese and Indian mandarins. Type F chromosome was present only in some mandarins originating in Japan, which could
thus be distinguished from mandarins originating in other areas. This study is the first report of type F chromosome in citrus.
The Vietnamese mandarins we studied were the only one shaving type A, B, C, D and E chromosomes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Genome-specific markers of tetraploid wheats and their putative diploid progenitor species 总被引：4，自引：0，他引：4
The objective of this study was to isolate genome‐specific markers from the genomes of tetraploid wheats and the putative donor diploid species on the basis of random amplified polymorphic DNA analysis followed by cross‐hybridization. Twenty different Triticum and Aegilops species and accessions were analysed by polymerase chain reaction (PCR) using 30 random primers. The polymorphic PCR fragments were then isolated, labelled and used in cross‐hybridization screenings. The hybridization results established that one marker was specific to the Ae. speltoides S genome, two to the A genome, one to the B genome and five to the G genomes of polyploid species (and to the genomes of the corresponding progenitor species). Four markers were identified that were specific to both the B and G genomes. Analysis of the Triticum and Aegilops species and accessions supported the notion that Ae. speltoides is more closely related to the B and G genomes of polyploid wheat species than were other members of the Sitopsis section. The data also indicated that the B and G genomes had originated from different accessions of Ae. speltoides. 相似文献
8.
C-banded karyotypes and meiotic abnormalities in germplasm derived from interploidy crosses in Avena
C-banded karyotypes of somatic chromosomes and meiotic abnormalities were investigated in four crown rust resistant lines
derived from interploidy crosses in Avena.C-banding revealed that line N770-165-2-1 contained a 6C/21translocation while line DCS1789 contained a pair of A. strigosa chromosomes substituted for A. sativachromosome 12. Line JR2-3-3-B contained both the 6C/21 translocation and the pair of substituted A. strigosachromosomes, but line MAM17-4 contained neither. Although meiotic irregularities, including mispositioned bivalents, occurred
in all four lines and in their F1 hybrids with A. sativa, the percentages of normal meiosis ranged from 75.4 to 88.6%. This allowed for stability of line performance and for their
use as breeding stocks.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
9.
Summary Cytological studies of wild diploid Arachis species in the same section of the genus (sect. Arachis) as the cultivated peanut A. hypogaea L. show, with one exception, a karyotype characterized by the presence of 9 pairs of larger chromosomes and one pair of small (A) chromosomes. The exceptional species A. batozocoi
Krap. et Greg. has a more uniform karyotype. Interspecific hybrids between diploid species of similar karyotype have moderate to high pollen stainability, those involving A. batizocoi have zero pollen stainability and a very irregular PMC meiosis. Such infertile hybrids are the most likely to produce fertile, stable amphidiploids on doubling the chromosome complement. It is suggested that the cultivated peanut could have originated from such a sterile interspecific hybrid and on morphological and phytogeographic grounds the most likely genome donors are A. cardenasii (nomen nudum) and A. batizocoi of the species within section Arachis, which have been collected up to the present time.Paper number 5560 of the Journal Series of the North Carolina Agricultural Experiment Station, Raleigh, NC 27650 相似文献
10.
Summary Experiments were carried out for adding the chromosome carrying resistance to beet root nematode (Heterodera schachtii) from the wild Beta species of the section Patellares (B. procumbens, B. webbiana and B. patellaris) to the genome of B. vulgaris. Preliminary experiments indicated that crosses between the wild species and B. vulgaris cultivars of the mangold type yielded on average more viable F1 hybrids than crosses with sugar and fodderbeet. However, crossability varied strongly between individual parental combinations. It was concluded that most types of B. vulgaris can be hybridized with the wild species of the section Patellares if a sufficient number of pair-crosses is made. Crosses between diploid cultivars or species of the section Vulgares and diploid wild species of the section Patellares yielded many hybrids which, however, were highly sterile. From crosses between tetraploid B. vulgaris and the wild species a great number of viable allotriploid and allotetraploid hybrids was obtained. In the backcross progenies of allotriploid hybrids 26% alien monosomic additions occurred, of which 4.1% carried the resistance bearing chromosome of B. procumbens or B. patellaris. The programme will be continued by sereening progenies of the resistant monosomic addition plants for the occurrence of resistant disomic introgression products. 相似文献
11.
Summary A Giemsa-C-banded karyotype of a partial amphiploid, Triticum turgidum L. var. durum cv. Nodak × Agropyron intermedium (Host) P.B., called MT-2, was analyzed. MT-2 is a winterhardy grasslike octoploid germplasm which survived 5 winters in Montana, and its seed weight is 3 times that of A. intermedium seed. The MT-2 C-banding karyotype shows 6 chromosome pairs each of the A and B wheat genomes with 3A and 4B missing. Chromosomes 1B and 2B are involved in a reciprocal homozygous translocation (T1BS·2BS, T1BL·2BL) which was also confirmed by a nucleolus-associated quadrivalent in an MT-2 × durum wheat backcross. In addition to the wheat chromosomes, MT-2 consistently shows 16 A. intermedium chromosome pairs which are designated from A to P. These chromosomes show C-banding patterns similar to those reported earlier in the literature. A large amount of C-banding polymorphism and structural rearrangements in A. intermedium itself presently make a definite chromosome assignment to the homeologous groups of the Triticeae difficult. The data presented are crucial for further directed manipulation of this germplasm aimed at producing valuable chromosome additions and substitutions in wheat.contribution No. J-2767 from Montana Agric. Exp. Stn. 相似文献
12.
F1 hybrids of triticale × rye derived from commercial varieties were backcrossed to the respective triticale parent. Selfing of the backcross generation yielded a large number of 4× triticales containing a genetically balanced wheat genome. This indicates that the 28-chromosome F1 plants with the genomic constitution of ABRR produced functional 14-chromosome gametes in high frequency each with a complete wheat and rye genome. The cytological mechanism leading to the formation of tetraploid triticales is described. The chromosomal constitution of the wheat genome in the progenies of 30 back cross plants was analysed by the C-banding technique. One offspring possessed a complete B genome of wheat. The production of tetraploid triticale through backcrossing in comparison to selfing the ABRR hybrid is largely independent of the genotype; it leads to new tetraploids in just three generations and it reduces the chance of translocations between the homoeologous wheat chromosomes. The possibility of studying the effect of different mixtures of chromosomes of the A and B genomes of wheat on the phenotype of the tetraploid triticale is discussed. 相似文献
13.
Summary Colchicine induced tetraploid (2n=4x=36) Brachiaria ruziziensis were used as female parent in crosses with apomictic tetraploid species (2n=4x=36) Brachiaria decumbens and Brachiaria brizantha. Tetraploid B. ruziziensis pollinated with B. decumbens set significantly more seed than selfed or crossed with B. brizantha. The crossability between B. ruziziensis and B. decumbens is also better than between B. ruziziensis and B. brizantha. In addition, hybrid seedlings obtained in crosses involving B. brizantha are more frequently lethal. All the viable F1 hybrids are tetraploid with 36 chromosomes. Meiotic chromosome behaviour suggest that the three species belong to the same genomic group and therefore the same agamic complex. Chromosome associations at metaphase I do not allow to identify fertile and sterile hybrids. The interspecific hybrids averaged a lower fertility than their female parent, but some hybrids were more fertile than their apomictic male parent. 相似文献
14.
Summary The regular meiotic behaviour of the cultivated oat Avena sativa (2n=6x=42) is genetically controlled. The factors which control the diploid-like meiotic behaviour also restrict the amount of pairing that occurs between alien chromosomes and their homoeologues in A.sativa, and hence increases the difficulties of introducing desirable variation from wild species into the cultivated oat. A genotype of the diploid species A.longiglumis which interferes with the regular meiotic behaviour of A. sativa can be used to induce pairing between alien chromosomes and their corresponding chromosomes in A. sativa. Using this procedure the dominant gene conferring mildew resistance has been transferred from the tetraploid weed species A. barbata into the cultivated oat. 相似文献
15.
Summary Cytological investigations of 50 wild Cucumis introductions revealed the presence of three tetraploid species with 2n=48 chromosomes, and one hexaploid species with 2n=72 chromosomes, while all other species are diploid containing 2ns=14 or 2n=24 chromosomes. Two of the tetraploid species, C. heptadactylus (P.I. 282446), and a species related to C. zeyheri (P.I. 273192, 299570, 299571, and 299572) are natives of South Africa, while C. aculeatus (P.I. 193967, 196844, 273648, 273649, and 273650) is found in Ethiopia. The hexaploid, C. figarei (P.I. 343699, 343700, 343701), is a native of Nigeria. All polyploids are perennial, have efficient vegetative reproduction systems, and may have originated from the spontaneous formation of polysomatic cells.Supported by the Colorado State University Experiment Station and published as Scientific Series Paper No. 2089. 相似文献
16.
Summary The possibility of combining anew the genomes of wild and cultivated progenitors of triploid S. x juzepczukii and pentaploid S. x curtilobum by following the known evolutionary pathway of these species was investigated.The resynthesis of S. x juzepczukii was easy, and a wide range of synthetic forms was bred. Among these were forms with higher frost resistance (-5°C) than has been found in natural S. x juzepczukii. The total tuber glycoalkaloid content of several synthetic hybrids was lower than or as low as that of natural clones. Most synthetic hybrids were more vigorous than natural S. x juzepczukii and produced about the same types of tubers as are found in the natural range of variation. The best diploid parents were found in the species S. goniocalyx.The attempt to resynthesize pentaploid S. x curtilobum has not been successful but tetraploid plants were obtained in the process. An explanation for the occurrence of tetraploids resulting from triploid x tetraploid and/or diploid crosses is offered.The newly bred tetraploids contain at least one genome from S. acaule (possibly two) and hybridize easily with ssp. andigena. They thus provide a means for the transfer of S. acaule germ plasm into the tetraploid cultivated gene pool which would profit from the frost resistance of S. acaule. 相似文献
17.
N. Inomata 《Euphytica》2003,133(1):57-64
The cytogenetic study was investigated in the intergeneric F1 hybrid, F2and backcross progenies (BC1). The plants used were Brassica juncea(2n=36) and Diplotaxis virgata(2n=18). Three intergeneric F1 hybrids between two species were produced through ovary culture. They showed 36 chromosomes. It might consist one genome
of B. juncea and two genomes of D. virgata. The morphology of the leaves resembled that of B. juncea. The color of the petals was yellow that was like in D. virgata. The size of the petal was similar to that of B. juncea. The mean pollen fertility was15.3% and the chromosome associations in the first meiotic division were(0–1)IV+(0–2)III+(8–12)II+(12–20)I. Many F2 and BC1seeds were harvested after open pollination and backcross of the F1 hybrids withB. juncea, respectively. The F2seedlings showed different chromosome constitutions and the range was from 28 to54 chromosomes. Most seedlings had 38chromosomes
followed by 36, 40 and 54. The BC1 seedlings also showed different chromosome constitutions and the range was from 29 to 62. Most seedlings had both 40and 54
chromosomes followed by 36, 46 and52. In the first meiotic division of F2 and BC1 plants, a high frequency of bivalent associations was observed in all the various kinds of somatic chromosomes. Many F3 and BC2 seeds were obtained by self-pollination and open pollination of both F2 and BC1 plants, and by backcrossing both F2 and BC1plants with B. juncea, respectively,especially, three type progeny with 36, 40or 54 chromosomes. The somatic chromosomes of the F3 and BC2 plants were further investigated. The bridge plants between B. juncea and D. virgata with 36 chromosomes may be utilized for breeding of other Brassica crops as well as B. juncea.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
18.
Y. H. Lee 《Euphytica》1991,54(3):251-254
Summary Ten Aranda cultivars commercially grown in Singapore were selected to study their genomic constitutions and flower characteristics. Cytological evidence and breeding records of these cultivars showed that they are of three genomic classes. Four of them are diploid with AV genomes (one Arachnis and one Vanda genome), another four are triploid with AVV genomes and the remaining two are tetraploid with AVVV genomes. Sizes of flowers as well as of sepals and petals generally show significant increases from diploid to tetraploid. This trend reflects the increasing influence of Vanda resulting from additional one and two Vanda genomes in triploid and tetraploid respectively as compared to diploid cultivars. Among the three genomic classes, diploid cultivars generally bear less flowers per spray than those of triploid and tetraploid although exceptions may occur. There is no clear trend in the length of inflorescences although diploid cultivars tend to have less compact spray with flowers more distantly spaced out. 相似文献
19.
Cytogenetic characterization by karyotyping and determination of DNA content by flow cytometry of seven cultivated varieties
of Chenopodium was performed. Chenopodium quinoa cultivar Barandales and C. berlandieri subsp. nuttalliae cultigens Huauzontle, Quelite and Chia roja showed 2n = 4x = 36, x = 9. Statistically insignificant genome size differences for studied varieties ranged from 2.96 pg/2C (1 Cx = 724 Mbp) in C. quinoa to 3.04 pg/2C (1 Cx = 743 Mbp) in Huauzontle. Karyotype analyses revealed the presence of nine groups of four metacentric chromosomes, including
two pairs of chromosomes with satellites. The first pair of satellites was located on the largest pair of chromosomes and
the second on a different pair of chromosomes in all accessions analyzed. Variation among varieties was evident in chromosome
size, genome length (GL) and the position of satellites. Chia roja exhibited greatest GL (58.82 μm) and biggest chromosomes
(2.04 μm). Huauzontle showed the smallest GL (45.02 μm) and shortest chromosomes (1.60 μm). Comparison of GL in studied taxa
was statistically significant and allowed to define three groups according to the use given to these plants. These data indicate
that they are small, very stable genomes in terms of DNA content, and they support the allotetraploid origin(s) of C. berlandieri subsp. nuttalliae and C. quinoa. 相似文献
20.
Karyotype analysis and interspecific hybridisation in three perennial Sesbania species (Leguminosae)
Summary The somatic chromosome number in Sesbania sesban var. nubica, S. goetzei and S. keniensis (Leguminosae; Papilionoidae) was found to be 2n=12. These findings were in agreement with earlier reports on S. sesban and S. keniensis. The chromosome number 2n=12 is a new record for S. goetzei. Similarities in karyotypes were found in the three species. All species had one pair of long metacentric chromosomes; the second pair was submedian, followed by four smaller pairs of metacentric chromosomes. Nucleolar organiser regions in the form of satellites were found on the short arm of the fourth chromosome pair in S. sesban and S. keniensis. Interspecific crosses in all possible combinations were carried out, resulting in pod and viable seed formation for the crosses S. sesban x S. goetzei, S. sesban x S. keniensis, S. goetzei x S. sesban and S. goetzei x S. keniensis. The two crosses with S. keniensis as a female parent were unsuccessful. The hybrid plants established normally and produced viable seeds. 相似文献