共查询到20条相似文献,搜索用时 46 毫秒
1.
Delong Yang Wei Li Sheng Li Xiuling Yang Jiling Wu Ziyi Cao 《Plant Growth Regulation》2007,51(1):63-71
The purpose of this study was to understand factors affecting in vitro embryo rescue culture from hybrids between diploid
and tetraploid varieties of grape in creation new triploid germplasm resources. The effects of different media, removal ages
of immature seeds and reciprocal crosses of parents on the germination and seedling survival of immature seeds from crosses
between diploid and tetraploid grape varieties by in vitro embryo rescue culture were investigated. The results indicated
that the medium consisting of NN-1969 + IAA 1.75 mg l−1 + GA3 0.35 mg l−1 + CH 400 mg l−1 + AC 2.0 g l−1 was better than other media. The optimal removal age of immature seeds for the best development of embryos was 35–45 days
after pollination (DAP). The percentage of germination (PG) for immature seeds and the percentage of seedling survival (PSS)
for immature seeds for diploid varieties used as female parents were 10.72% and 4.35% higher than when tetraploid varieties
were used as female parents respectively. A total of 41 hybrid progenies from eight combinations were obtained, made up of
17 diploid, 9 tetraploid, 14 aneuploid, and 1 triploid progeny as determined by root-tip chromosome identification. The triploid
progeny was from Fujiminori (2n = 4x = 76) × Jingxiu (2n = 2x = 38). These results implied that it was feasible to extend the hybridization range of grape and to create new germplasm
resources by in vitro embryo rescue based on the conventional hybridization. The NN-1969 medium supplemented with GA3 and IAA was more propitious to the development of immature seeds sampled at about 45 DAP. It was easier to obtain plants using
diploid as female parent, but triploid progeny was only obtained using tetraploid as female parent. 相似文献
2.
Juan-Carlos Herrera Juan-Vicente Romero Gloria-Cecilia Camayo Creuci-Maria Caetano Hernando-Alfonso Cortina 《Tropical plant biology》2012,5(3):207-217
Interspecific hybrids involving the cultivated C. arabica (2n = 4x = 44, EaEaCaCa) and two related diploid species (2n = 2x = 22), C. eugenioides (EE) and C. liberica (LL), were produced and analyzed for their relative genome affinity using different complementary approaches, including chromosome association analysis, genomic in situ hybridization (GISH) and pollen fertility. The mean arm pairing frequency (c) and the relative affinity index (x) of triploid hybrids with known genome combinations were used as a measure of chromosome homology. Triploid hybrids were highly sterile as a result of meiotic abnormalities (fertility ranged from 1 to 15 %). Nevertheless, all hybrids exhibited a significant occurrence of genome affinities (x = 0.96 for EaCaE and 0.81 for EaCaL). Further analysis using the GISH approach revealed that C. eugenioides was more closely related to C. arabica than to C. liberica, which was in agreement with the ancestral history of the allotetraploid C. arabica. The absence of incompatibility barriers at the stylar level in the flowers of the triploid hybrids indicates the possibility of desirable gene transfer through breeding strategies. 相似文献
3.
Dawei Li Yifei Liu Xinwei Li Jingyun Rao Xiaohong Yao Caihong Zhong 《Tree Genetics & Genomes》2014,10(5):1451-1463
Understanding the extent and partitioning of crop genetic diversity is necessary for conserving and utilizing their genetic potentials for breeding. In the present study, fluorescence-labeled amplified fragment length polymorphism markers were used to characterize the genetic diversity and relationships of 79 cultivars and also of 122 F1 hybrids which resulted from six kiwifruit interploid crosses. A high level of mean genetic diversity was detected (Hj > 0.22) for all cultivars investigated, without significant differences among diploids (2x), tetraploids (4x), and hexaploids (6x). This suggested that no significant genetic erosion occurred in these cultivars, which were directly selected from natural resources or created from crosses. The Unweighted Pair Group Method with Arithmetic Mean analysis of the genetic dissimilarity between cultivars showed three main groups mostly based on their three ploidy levels. Among these, the red-fleshed cultivars which were originally derived from ‘Hongyang’ clustered into one subgroup of group I, suggesting their unique genetic background despite they were marked as different cultivars used in the current kiwifruit industry. By analyzing the genetic variation of hybrids with variable ploidy levels, our genetic analyses further revealed that interploid crosses can increase the genetic diversity of F1 offsprings, especially from the parental combinations of 6x–2x and 6x–4x, in which both parents showed significant differences in morphology and genetic backgrounds. Based on these findings, strategies were proposed for the conservation and utilization of the current kiwifruit genetic resources for future breeding programs. 相似文献
4.
A. Carvalho H. Guedes-Pinto J. S. Heslop-Harrison J. Lima-Brito 《Plant Molecular Biology Reporter》2008,26(1):46-52
The DNA hypomethylation effect of 5-azacytine (5-AC; a cytosine analog) is widely known. This agent has been used for rRNA
gene expression studies of Triticeae amphiploids and hybrids regarding rye rRNA genes suppression caused by the wheat nucleolar dominance phenomenon. However,
this situation is reverted by 5-AC treatment which activates rye rRNA gene expression as it has been intensively observed
in triticale. For nucleolar dominance studies, we produced F1 multigeneric hybrids (AABBRHch; 2n = 6x = 42) from crosses between the triticale cultivar ‘Corgo’ (AABBRR; 2n = 6x = 42) and the tritordeum cultivars HT9 and HT31 (AABBHchHch; 2n = 6x = 42). The hybrid seeds were germinated in a low concentration of 5-AC (treatment) and in distilled water (nontreated control
plants). Silver nitrate staining performed in one 5-AC-treated F1 hybrid revealed a reduced number of interphase cells with
seven nucleoli, metaphases with eight Ag-NORs, and neocentromeres in the long arm of three wheat chromosomes. Nontreated hybrids
presented six Ag-NORs per mitotic metaphase cell and a maximum of six nucleoli per interphase because of the 1R Ag-NOR suppression.
No neocentromere was found in the control F1 hybrid plants. Both treated and nontreated seedlings were subsequently evaluated
by fluorescent in situ hybridization performed with genomic and repetitive DNA probes to identify Hch and rye genomes, to confirm Ag-NORs location, and to detect inactive rDNA loci. DAPI counterstaining was also helpful for
the detection of neocentromeres in the long arm of three wheat chromosomes. This study allowed us to suggest that 5-AC treatment
specifically induced wheat neocentromeres in the F1 multigeneric triticale × tritordeum hybrids. 相似文献
5.
Hypocotyl, cotyledon and zygotic embryo explants from two Tunisian Cucumis melo L. cultivars Beji and Maazoun, cultured on the MS medium added with 2,4-D (0.25–1 mg l−1) and BA (0.10–0.50 mg l−1), produce calluses with somatic embryos after 3 weeks of culture. For Beji c.v. the highest percentage (62.50%) of embryogenesis
was observed for cotyledons. The average embryo number per callus was 10.40. Embryogenesis induction for zygotic embryos reached
33.50% with 29 embryos per callus. The embryogenesis ability of hypocotyls did not exceed 12.50% (2.50 embryos per callus).
Somatic embryogenesis for Maazoun c.v. explants was less efficient. Embryos formation was observed only for cotyledons (29%)
and zygotic embryos (25%). Cotyledonary staged embryos, when transferred to hormone free MS medium, germinated. The maximum
germination rates were 51.50 and 44.50%, respectively for Maazoun and Beji c.v. The highest percentage (36.50%) of survival
plants was noted for Beji c.v. Regenerants were diploids (2n = 2x = 24) and morphologically similar to their parents issued from seeds. 相似文献
6.
Wen Liu Xuesen Chen Guanjun Liu Qing Liang Tianming He Jianrong Feng 《Plant Cell, Tissue and Organ Culture》2007,88(3):289-299
Embryo rescue technique was used successfully to produce interspecific hybrids by crossing peach (P. persica) as a female parent with apricot (P. armeniaca) and plum (P. salicica). In those crosses that had ‘Yuhualu’ or ‘Zhonghuashoutao’ as female parents, hybrid embryos aborted from the 7th or 8th
week after pollination mainly due to post-pollination incompatibility. An embryo rescue protocol was established to rescue
such embryos and recover hybrid plants. Modified half-strength MS medium containing 4 mg l−1 6-BA and 0.5 mg l−1 IBA produced up to 90% germination in the embryos. Modified MS medium with 1.0 mg l−1 6-BA and 1.0 mg l−1 IBA gave the highest bud induction and multiplication whereas modified MS medium containing 0.5 mg l−1 IAA and 0.2 mg l−1 NAA gave the best rooting percentage. All the hybrids obtained using this embryo rescue technique were verified using simple
sequence repeat (SSR) markers. A series of pollen treatments were carried out to partially overcome pre-pollination incompatibility,
and it was found accidentally that pollen treatment with electrostatic field not only improved pollen germination but also
increased the multiplication coefficient of embryo-induced shoots. 相似文献
7.
Hitoshi Mizuochi Hironori Matsuzaki Takehiko Moue Keiichi Okazaki 《Sexual plant reproduction》2009,22(1):27-36
Most Liliaceae plants have the tetrasporic Fritillaria-type embryo sac and normally form diploid embryos and pentaploid endosperms derived
from a 4:1 maternal-to-paternal genome ratio (4m:1p) after double fertilization. Here we characterize embryo sac and endosperm
formation in Tulipa spp. of Liliaceae. Chromosome analysis using seeds derived from 2x × 2x crosses of Tulipa
gesneriana (2n = 2x = 24) identified diploid chromosome number in the endosperm. Similarly, flow cytometric analysis confirmed diploid endosperm
formation in T. gesneriana, T. fosteriana (2n = 2x = 24) and T. greigii (2n = 2x = 24). To further study the possible mechanism of diploid endosperm formation, we made interploidy crosses of triploid (2n = 3x = 36) × diploid in which aneuploid seeds with various chromosome numbers (2n = 25–36) were produced. Again, flow cytometric analysis confirmed the same ploidy level in both embryos and endosperms at
all aneuploidy levels, suggesting that only a single haploid polar nucleus contributes to endosperm formation at fertilization.
Histological observation further confirmed the physical separation of two polar nuclei by a large vacuole in the Fritillaria-type
embryo sac of T.
gesneriana that appeared to prevent the fusion of the two polar nuclei that originated at the micropylar and chalazal ends before fertilization.
Taken together, these results indicate that diploid endosperms (1m:1p) are normally formed in Tulipa spp. by fusion of the micropylar polar nucleus (n) and a spermatid (n) but not by normal triple fusion. We also show that tulip endosperm partially overcomes the triploid block mechanism that
occurs in interploidy crosses. Based on these observations, the possible role of triple nuclear fusion in double fertilization
is discussed. 相似文献
8.
Xiaojie Li Guanpin Yang Yuanyuan Shi Yizhou Cong Shi Che Shancun Qu Zhiling Li 《Journal of applied phycology》2008,20(6):1097-1102
Eighteen microsatellite markers were used to determine the genetic distances between the parental gametophyte clones of 14
Laminaria hybrids, which were then used to establish a linear relationship with the heterosis (hybrid vigor) of economic traits including
yield, mean blade try weight, mean blade fresh weight, blade length, blade width and mean blade thickness using regression
analysis. Significant regression was found between the genetic distance (x) and the heterosis (y) of yield (y = 115.10x − 77.97,
r = 0.8151, p = 0.00038), mean blade dry weight (y = 115.23x −77.97, r = 0.8154, p = 0.00038), mean blade fresh weight (y = 100.08x − 57.85, r = 0.7306, p = 0.0030) and blade length (y = 204.11x − 46.77, r = 0.6963, p = 0.00566). The prediction of the heterosis of Laminaria hybrids with the genetic distance between parental gametophyte clones will facilitate the selection of elite Laminaria hybrids by avoiding the time-consuming and labor-intensive trait evaluation of a large number of hybridization combinations. 相似文献
9.
Domingo Ruvalcaba-Ruíz Guadalupe Palomino Javier Martínez Ignacio Méndez Benjamín Rodríguez-Garay 《In vitro cellular & developmental biology. Plant》2012,48(1):144-152
The effect of para-fluorophenylalanine (PFP) on the production of trisomic plants of Agave tequilana Weber var. Azul produced through somatic embryogenesis was investigated. Normal diploid plants with 2n = 2x = 60 were obtained in the control treatment and with 4 mg L−1 PFP exposure, while use of 8 and 12 mg L−1 PFP led to production of trisomics with 2n = 2x = 61. Normal diploid plants showed a bimodal karyotype with five pairs of large chromosomes and 25 pairs of small chromosomes.
Trisomic plants also had a bimodal karyotype with a group of three chromosomes in position five of the chromosome set. More
than 13 homologous chromosome pairs exhibited structural changes. Differences in chromosome arm ratio (long arm/short arm)
were also found in eight chromosome pairs; all these aberrations in the chromosome complement of trisomic plants were probably
caused by inversions, deletions, and/or duplications produced by high concentrations of PFP. The gross chromosome structural
changes and the presence of a single extra chromosome could have been induced by the effect of PFP on the mitotic spindle
by inducing nondisjunction of sister chromatids, resulting in hyperploids (2n + x) and hypoploids (2n − x). Flow cytometric analysis of nuclear DNA content was performed using nuclei isolated from young leaves of normal and trisomic
plants. The 2C DNA content of 8.635 pg (1Cx = 4,223 Mbp of trisomic plants was different (p < 0.001) than that of normal plants (2C DNA = 8.389 pg (1Cx = 4,102 Mbp). The difference in genome size was correlated with the large structural changes in the trisomic plant genomes. 相似文献
10.
Faure N Serieys H Bervillé A Cazaux E Kaan F 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(4):652-660
Hybridisation between the annual diploid sunflower (Helianthus annuus) and the perennial diploid species Helianthus mollis and Helianthus orgyalis was obtained by means of a normal crossing procedure or embryo rescue. Hybridisation success was low. All plants examined
cytologically appeared to be diploid. However, the phenotypes of these diploids were not intermediate between the parents
and, despite great variation, they resembled the female parent-type predominantly. Thirty five percent of plants issued from
sunflower pollinated with perennial Helianthus had a phenotype resembling the female sunflower parent. On average, only 5% of the minimum number of expected RAPD and RFLP bands from male parents were recovered in plants produced
from mature seeds after pollination of sunflower by H. mollis. More hybrids were found among plants obtained from embryo rescue, with an average of 25% of the male parent bands recovered
per plant. Analysis of individual plants indicated the occurrence of various levels of hybridisation. There was a significant
positive correlation between the number of phenotype traits related to hybrid status and the number of bands derived from
the male parent. A single hybrid plant might possibly represent the product of a ’normal’ hybridisation event. The mechanisms
behind these unusual events and the consequences for the breeder are discussed.
Received: 23 March 2001 / Accepted: 28 June 2001 相似文献
11.
Rescuing abortive inter-EBN potato hybrids through double pollination and embryo culture 总被引:1,自引:0,他引:1
Summary Regeneration of inter-EBN hybrids among potato species was achieved using embryo rescue techniques. Tetraploid hybrids between 4x(2EBN) Solanum stoloniferum x 4x(4EBN) S. tuberosum Gp. Andigena as well as diploid hybrids between 2x(1EBN) S. chancayense x 2x(2EBN) S. chacoense were obtained by culturing immature hybrid embryos in nutrient medium. Identification of appropriate embryo developmental stages was critical in developing a suitable protocol for rescuing viable hybrid embryos. The use of IVP clones as the second pollinator in 4x(2EBN) x 4x(4EBN) crosses reduced premature fruit drop and helped to identify triploid hybrids. Morphological and cytological examination confirmed true hybridity for a few of the regenerated plants. Male sterility and meiotic abnormalities were characteristic of the hybrids. Several S. stoloniferum-Andigena hybrids were successfully backcrossed to Gp. Andigena.Cooperative investigation of Vegetable Crops Research Unit, USDA, Agricultural Research Service, and the Wisconsin Agricultural Experiment Station
Note: Reference to a specific brand or firm name does not constitute endorsement by the U.S. Department of Agriculture over others of similar nature not mentioned 相似文献
12.
Polyploidization is an important speciation mechanism for all eukaryotes, and it has profound impacts on biodiversity dynamics
and ecosystem functioning. Green fluorescent protein (GFP) has been used as an effective marker to visually screen somatic
hybrids at an early stage in protoplast fusion. We have previously reported that the intensity of GFP fluorescence of regenerated
embryoids was also an early indicator of ploidy level. However, little is known concerning the effects of ploidy increase
on the GFP expression in citrus somatic hybrids at the plant level. Herein, allotetraploid and diploid cybrid plants with
enhanced GFP (EGFP) expression were regenerated from the fusion of embryogenic callus protoplasts from ‘Murcott’ tangor (Citrus reticulata Blanco × Citrus sinensis (L.) Osbeck) and mesophyll protoplasts from transgenic ‘Valencia’ orange (C. sinensis (L.) Osbeck) expressing the EGFP gene, via electrofusion. Subsequent simple sequence repeat (SSR), chloroplast simple sequence
repeat and cleaved amplified polymorphic sequence analysis revealed that the two regenerated tetraploid plants were true allotetraploid
somatic hybrids possessing nuclear genomic DNA of both parents and cytoplasmic DNA from the callus parent, while the five
regenerated diploid plants were cybrids containing nuclear DNA of the leaf parent and with complex segregation of cytoplasmic
DNA. Furthermore, EGFP expression was compared in cells and protoplasts from mature leaves of these diploid cybrids and allotetraploid
somatic hybrids. Results showed that the intensity of GFP fluorescence per cell or protoplast in diploid was generally brighter
than in allotetraploid. Moreover, same hybridization signal was detected on allotetraploid and diploid plants by Southern
blot analysis. By real-time RT-PCR and Western blot analysis, GFP expression level of the diploid cybrid was revealed significantly
higher than that of the allotetraploid somatic hybrid. These results suggest that ploidy level conversion can affect transgene
expression and citrus diploid cybrid and allotetraploid somatic hybrid represents another example of gene regulation coupled
to ploidy. 相似文献
13.
Barba-Gonzalez R Lokker AC Lim KB Ramanna MS Van Tuyl JM 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2004,109(6):1125-1132
Sixteen Oriental and 12 Asiatic cultivars were crossed in 158 different combinations. A total of 708 F1 hybrids were obtained from 86 of the different combinations of 15 Oriental and 11 Asiatic cultivars. Because the Lilium cultivars (2n=2x=24) used for the production of these hybrids belong to two different taxonomic sections—Archelirion (O) and Sinomartagon (A), respectively—the F1 hybrids (OA) could be obtained only through embryo, embryo sac rescue, ovary slice or ovule culture. Most of the F1 hybrids were highly sterile (did not produce viable n gametes) due to the failure of chromosome pairing. However, in a few cases F1 plants were found that produced viable 2n pollen at variable frequencies. These 2n pollen grains were successfully used for the production of backcross progenies. Using genomic in situ hybridization we found intergenomic recombinant chromosomes in the sexual polyploid progenies. These results indicate that there are effective prospects for combining important horticultural traits from the two main groups of cultivars of lilies through sexual polyploidization. 相似文献
14.
Wei Zhou Jianyi Zhu Songdong Shen Shan Lu Jinfeng Wang Jianrong Xu Pu Xu 《Journal of applied phycology》2008,20(5):991-999
Nuclear divisions of carpospores, conchocelis and conchospores of Porphyra yezoensis, P. haitanensis, P. katadai var. hemiphylla and P. oligospermatangia from China were investigated. The observations showed diploid chromosome numbers of 2n = 6 for P. yezoensis and P. oligospermatangia, and 2n = 10 for P. haitanensis and P. katadai var. hemiphylla. For all four species, somatic pairing of chromosome sets was observed in late prophase. Sister chromosomes separated at
anaphase as mitosis took place in carpospores, conchocelis filamentous cells, conchosporangial branch cells and sporangial
cells (conchospore formation). Chromosome configurations of tetrad and ring-shaped in conchospore germination were observed,
demonstrating the occurrence of meiosis. The characteristics of diploid nuclear division in 2n = 6 species are the same as
those of 2n = 10 species. The influence of somatic pairing on nuclear division of diploid cells in Porphyra was discussed. 相似文献
15.
Leonardo Soriano Francisco de Assis Alves Mour?o Filho Luis Eduardo Aranha Camargo Mariangela Cristofani-Yaly Rodrigo Rocha Latado Camila de Andrade Pacheco Fernando Alves de Azevedo Beatriz Madalena Januzzi Mendes 《Plant Cell, Tissue and Organ Culture》2012,111(3):385-392
Protoplast fusion between sweet orange and mandarin/mandarin hybrids scion cultivars was performed following the model ??diploid embryogenic callus protoplast?+?diploid mesophyll-derived protoplast??. Protoplasts were isolated from embryogenic calli of ??Pera?? and ??Westin?? sweet orange cultivars (Citrus sinensis) and from young leaves of ??Fremont??, Nules??, and ??Thomas?? mandarins (C. reticulata), and ??Nova?? tangelo [C. reticulata?×?(C. paradisi?×?C. reticulata)]. The regenerated plants were characterized based on their leaf morphology (thickness), ploidy level, and simple sequence repeat (SSR) molecular markers. Plants were successfully generated only when ??Pera?? sweet orange was used as the embryogenic parent. Fifteen plants were regenerated being 7 tetraploid and 8 diploid. Based on SSR molecular markers analyses all 7 tetraploid regenerated plants revealed to be allotetraploids (somatic hybrids), including 2 from the combination of ??Pera?? sweet orange?+???Fremont?? mandarin, 3 ??Pera?? sweet orange?+???Nules?? mandarin, and 2 ??Pera?? sweet orange?+???Nova?? tangelo, and all the diploid regenerated plants showed the ??Pera?? sweet orange marker profile. Somatic hybrids were inoculated with Alternaria alternata and no disease symptoms were detected 96?h post-inoculation. This hybrid material has the potential to be used as a tetraploid parent in interploid crosses for citrus scion breeding. 相似文献
16.
Wang Xi-Ling Zhou Jin-Xing Yu Mao-De Li Zhen-Gang Jin Xiao-Yun Li Qi-You 《In vitro cellular & developmental biology. Plant》2011,47(3):434-440
Efficient plant regeneration is essential for successful transformation and in vitro polyploidy induction in mulberry. A high frequency (80%) of plant regeneration from hypocotyls occurred under in vitro conditions in mulberry (Morus multicaulis Poir.). We identified three key factors for enhancing successful regeneration based on earlier work: (1) hypocotyl position,
(2) the combination and concentration of growth regulators, and (3) the addition of AgNO3. The highest frequency of shoot regeneration was achieved using hypocotyl segments, which are proximal to apical meristems,
and the optimal culture conditions were Murashige and Skoog’s (MS) (Murashige and Skoog, 1962) basal medium supplemented with 3.0 mg l−1 6-benzylamino purine, 0.3 mg l−1 indole-3-acetic acid, 0.1% polyvinypyrrolidone, and 1.0 mg/l silver nitrate (AgNO3) under subdued light at 25 ± 2°C. Treating the shoots with 0.2% colchicine (dipping for 72 h) resulted in a 14% tetraploid
frequency, whereas a 20% tetraploid frequency resulted from using a 0.25% colchicine (dripping for 5 d) treatment, as determined
by chromosome number counts. The diploid plant chromosome number was 28 (2n = 2x = 28) and that of tetraploid plants was 56 (2n = 4x = 56). Regenerated shoots rooted easily in 8–10 d using half-strength basal MS medium with 0.5 mg l−1 indole-3-butyric acid and were successfully established in the soil. 相似文献
17.
J. Kato M. Mii 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(5-6):690-696
Differences in ploidy level were found in inter-specific hybrids obtained by reciprocal crosses between Primula sieboldii and P. kisoana. When P. sieboldii was used as the maternal parent, the inter-specific hybrids were triploids; when P. kisoana was the maternal parent, the inter-specific hybrids were diploids. The possibility of diploid female gamete formation in
P. sieboldii is discussed as a causal factor in the production of triploids occasionally found in crosses between diploids of this species.
Received: 28 December 1999 / Accepted: 10 January 2000 相似文献
18.
Chengtai Yang Ling Cao Weimin Wang Yi Yang Khalid Abbas Binlun Yan Hanping Wang Li Su Yuhua Sun Huanling Wang 《Environmental Biology of Fishes》2009,86(1):145-153
To obtain the phylogenetic relationship between diploid and tetraploid Misgurnus anguillicaudatus, the mitochondrial cyt b gene in the diploid and tetraploid weather loach were isolated and sequenced. The DNA sequences were analyzed using MEGA
3.0 software to determine the phylogenetic relationship. Forty-five variable sites among cyt b gene sequences and 18 amino acid substitutions occurred within the diploid and tetraploid loaches as deduced from the nucleotide
sequences analysis of the cyt b gene. The nucleotide pairwise distance between diploid and tetraploid loach ranged from 0.001 to 0.025. Phylogenetic analysis
revealed evolutionary relationships between diploid and tetraploid loach. Our results indicated a significant difference between
diploid and tetraploid loach about the cyt b gene. AMOVA analysis indicated that there were no significant genetic variations within diploid loaches (Fst = 0.2529, P > 0.05) and within tetraploid loaches (Fst = 0.0564, P > 0.05), neither. However, significant genetic differences were found between diploid and tetraploid loaches (Fst = 0.7634,
P < 0.05). Thus, it is concluded that no reproductive isolation was found within the same cytotypes of different localities,
but there was reproductive isolation between these two cytotypes. The diploid loach existed before the tetraploid loach in
nature. The present study is the first to describe the phylogenetic relationships of natural polyploidy weather loach using
mtDNA cyt b gene. 相似文献
19.
H.J. Clarke J.G. Wilson I. Kuo M.M. Lülsdorf N. Mallikarjuna J. Kuo K.H.M. Siddique 《Plant Cell, Tissue and Organ Culture》2006,85(2):197-204
The main constraint to the transfer of desired traits into cultivated chickpea from wild Cicer relatives is the presence of post-zygotic barriers which result in abortion of the immature embryo following interspecific hybridisation. Rescue of hybrid embryos in vitro and regeneration of hybrid plantlets could allow chickpea breeders to transfer desirable traits from wild relatives of chickpea. The development of embryo rescue techniques using selfed chickpea and selfed wild relatives is being used as a first step to protocols for wide hybrids. Optical microscopy studies of embryogenesis, in both selfs and hybrids, identified deleterious changes in the fertilised hybrid seed as early as 2–4 days after pollination in some crosses. These observations suggest that the appropriate time to rescue chickpea × C. bijugum hybrids is at the early globular stage of embryogenesis (2–7 days old), which requires the development of a complex tissue culture medium. In contrast hybrids between chickpea × C. pinnatifidum abort later (up to 15–20 days old) at the heart-shaped or torpedo stages, and are easier to rescue in vitro. Genotype also plays a significant role in the ability of immature selfed ovules to germinate in vitro. In this paper we report on the optimisation of␣protocols for rescueing immature embryos using selfed chickpea and its wild relatives in ovule, and subsequently to regenerate plantlets. 相似文献
20.
We describe a new karyotype for Cavia magna Ximenez, 1980 from an estuarine island and the karyotype of Cavia aperea Erxleben, 1777 from an adjacent mainland. The species have differences in diploid number (2n), autosomal fundamental number,
quantity, and distribution of heterochromatin as dissimilar distributions of the nucleolus-organizing regions (Ag-NORs). The
C. aperea karyotype has a diploid number of 64 as previously reported for C. aperea and most other Cavia species. In contrast, this new C. magna karyotype exhibits a variant diploid number of 2n = 62, considering that previous work reported a karyotype of 2n = 64 for
C. magna. The discovery of a distinct diploid number within C. magna represents the first record of intra-specific chromosomal variation in a species of Caviidae. The diploid number of 2n = 62,
heterochromatin quantity, Ag-NOR distributions, and inversed X chromosome from this population of C. magna are as seen in the geographically proximate (Cavia intermedia Cherem Olimpio and Ximenez; intermediate Cavy). These data provide further evidence supporting C. magna as the sister species of C. intermedia. 相似文献