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Jan, C. C., J. M. Chandler e S. A. Wagner. "Induced tetraploidy and trisomic production of Helianthus annuus L." Genome 30, n.º 5 (1 de outubro de 1988): 647–51. http://dx.doi.org/10.1139/g88-109.
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Seedlings of the Helianthus annuus inbred lines P21 and HA89 were treated with colchicine to study chromosome doubling. Frequency of tetraploids, meiotic chromosome pairing, pollen stainability, and fertility were examined. Five-hour colchicines treatments at 0.15%, pH 5.4, with 2% dimethyl sulfoxide resulted in tetraploid sectors on 42% of P21 and 11% of HA89 plants. Tetraploids had larger disk florets and larger pollen grains. Otherwise, tetraploid plants were morphologically similar to their diploid progenitors. Tetraploidy in P21 was not stable, with plants having 2n = 4x = 65 to 70 chromosomes. Tetraploid plants of HA89 had reduced vigor and did not produce seed. At diakinesis, tetraploid P21 plants had an average of 0.85 univalents, 21.12 open bivalents, 6.66 closed bivalents, 0.21 trivalents, and 2.74 quadrivalents per cell. The number of chiasma per chromosome pair in P21 was reduced from 1.50 for diploid to 1.32 for tetraploid plants. Pollen stainability in tetraploid P21 was less than 50% and the plants produced an average of eight seeds per sibbed head, about 1% of normal seed set. Reciprocal crosses of diploid and tetraploid P21 produced four triploid plants. Backcrossing triploids to P21 produced 137 plants with 2n = 34 to 47 + t. Thirty-one of these plants were trisomies having 2n = 35.Key words: Helianthus annuus, tetraploids, triploids, trisomies.
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Weber, Gregory M., Mark A. Hostuttler, Kenneth J. Semmens e Brian A. Beers. "Induction and viability of tetraploids in brook trout (Salvelinus fontinalis)". Canadian Journal of Fisheries and Aquatic Sciences 72, n.º 10 (outubro de 2015): 1443–49. http://dx.doi.org/10.1139/cjfas-2014-0536.
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Brook trout (Salvelinus fontinalis) populations are threatened by introduction of invasive species, habitat loss, and habitat degradation in their native range and are a problem invasive species in western Unites States and Canada and in Europe. Stocking sterile triploids has been promoted as an approach to reduce negative effects of stocking of brook trout for recreational fishing on native fish populations. Crossing a tetraploid with a diploid is a method of triploid production that may help hatcheries meet demand. We induced tetraploidy in brook trout by application of 633 kg·cm−2 of hydrostatic pressure for 8 min at 70%–72.5% of the first cleavage interval. Yields of above 50% tetraploid progeny at hatching were readily achieved, although few animals reached 1 year of age. We crossed a male tetraploid with female diploid fish and produced interploid-triploids with eyeing rates in excess of 50%, demonstrating male tetraploids are fertile and capable of siring triploid progeny. Female tetraploid fish were reared to 16 months posthatching and possessed follicles in secondary vitellogenesis, suggesting tetraploid females are also fertile. Tetraploid induction rates in excess of 96% were achieved applying the same hydrostatic pressure treatment to zygotes of tetraploid × diploid crosses at 30 min postfertilization.
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Panopoulos, Andreas, Cristina Pacios-Bras, Justin Choi, Mythili Yenjerla, Mark A. Sussman, Rati Fotedar e Robert L. Margolis. "Failure of cell cleavage induces senescence in tetraploid primary cells". Molecular Biology of the Cell 25, n.º 20 (15 de outubro de 2014): 3105–18. http://dx.doi.org/10.1091/mbc.e14-03-0844.
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Tetraploidy can arise from various mitotic or cleavage defects in mammalian cells, and inheritance of multiple centrosomes induces aneuploidy when tetraploid cells continue to cycle. Arrest of the tetraploid cell cycle is therefore potentially a critical cellular control. We report here that primary rat embryo fibroblasts (REF52) and human foreskin fibroblasts become senescent in tetraploid G1 after drug- or small interfering RNA (siRNA)-induced failure of cell cleavage. In contrast, T-antigen–transformed REF52 and p53+/+ HCT116 tumor cells rapidly become aneuploid by continuing to cycle after cleavage failure. Tetraploid primary cells quickly become quiescent, as determined by loss of the Ki-67 proliferation marker and of the fluorescent ubiquitination-based cell cycle indicator/late cell cycle marker geminin. Arrest is not due to DNA damage, as the γ-H2AX DNA damage marker remains at control levels after tetraploidy induction. Arrested tetraploid cells finally become senescent, as determined by SA-β-galactosidase activity. Tetraploid arrest is dependent on p16INK4a expression, as siRNA suppression of p16INK4a bypasses tetraploid arrest, permitting primary cells to become aneuploid. We conclude that tetraploid primary cells can become senescent without DNA damage and that induction of senescence is critical to tetraploidy arrest.
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Bothmer, Roland von, Jan Flink e Tomas Landström. "Meiosis in interspecific Hordeum hybrids. IV. Tetraploid (4x × 4x) hybrids". Genome 30, n.º 4 (1 de agosto de 1988): 479–85. http://dx.doi.org/10.1139/g88-080.
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The meiotic pairing behaviour of 31 interspecific combinations of tetraploid Hordeum species are reported. The autoploid H. bulbosum with the II genomic constitution has no homology to the other species. The constitution of tetraploid H. murinum is not clear, but it is not homologous to other tetraploids. Hordeum marinum is a probable autoploid (XX) but with a very strong genetic regulation of pairing. The X genome is possibly found in H. secalinum and H. capense, both of which also possess the H genome in several diploids. Hordeum fuegianum, H. tetraploidum, H. jubatum, H. brachyantherum, and H. roshevitzii are segmental alloploids all with the same two partly homoeologous genomes. Hordeum depressum is probably a segmental alloploid with the H genome and with a very strong pairing regulation. Hordeum brevisubulatum is a pure autoploid with two homologous H genomes.Key words: Hordeum, interspecific hybrids, meiosis, tetraploids.
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Compton, Michael E., D. J. Gray e G. W. Elmstrom. "150 THE IDENTIFICATION OF TETRAPLOID REGENERANTS FROM COTYLEDONS OF DIPLOID WATERMELON AND THEIR USE IN BREEDING TRIPLOID HYBRIDS". HortScience 29, n.º 5 (maio de 1994): 450c—450. http://dx.doi.org/10.21273/hortsci.29.5.450c.
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Tetraploid individuals were identified among plants regenerated from cotyledons of diploid watermelon [Citrullus lanatus (Thunb.) Matsum. & Nakai] cultured in vitro. Tetraploid and diploid plants were distinguished by counting the number of chloroplast per guard cell pair. The mean number of chloroplasts was 19 and 11 for tetraploid and diploid plants, respectively. Self-fertile tetraploids were obtained from the diploid cultivars Mickylee, Jubilee II and Royal Sweet. `Dixielee' and `Minilee' tetraploids failed to set fruit. Progeny obtained from self-fertile tetraploids were crossed with diploid pollinators to produce triploid hybrid seed. All triploid plants produced seedless fruit that was superior or equal to fruit produced by currently available triploid hybrids. This demonstrates that tissue culture can be used to produce high quality tetraploid plants for use in triploid hybrid seed production.
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SMITH, K. F., R. J. SIMPSON, R. A. CULVENOR, M. O. HUMPHREYS, M. P. PRUD'HOMME e R. N. ORAM. "The effects of ploidy and a phenotype conferring a high water-soluble carbohydrate concentration on carbohydrate accumulation, nutritive value and morphology of perennial ryegrass (Lolium perenne L.)". Journal of Agricultural Science 136, n.º 1 (fevereiro de 2001): 65–74. http://dx.doi.org/10.1017/s0021859600008480.
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Tetraploidy or the use of diploid genotypes with genes conferring high water-soluble carbohydrate concentrations are two mechanisms to increase the nutritive value of perennial ryegrass. This experiment compared the morphology, nutritive value and diurnal variation in water-soluble carbohydrate (WSC) concentrations of 56-day-old plants from six perennial ryegrass cultivars grown under controlled environment conditions. Three of these cultivars were diploid (Melle, Aurora and Cariad) and three were tetraploids (Meltra, Prospero and AberOnyx) which had been derived from the respective diploid cultivars. Two of the diploid cultivars (Cariad and Aurora) had previously been selected for high concentrations of water-soluble carbohydrates. The tetraploid cultivars had fewer (mean 59), larger tillers than the diploids (mean 83). However, with the exception of Melle and Meltra the dry matter yield of the diploid cultivars was not significantly different from their tetraploid derivatives. The effect of tetraploidy on WSC concentrations was dependent on the genetic background of the cultivars. Melle, which had not been previously selected for increased WSC, had a significantly lower WSC concentration than its tetraploid derivative, Meltra. However, tetraploidy did not further increase the WSC concentration in those cultivars previously selected for high WSC concentrations. WSC concentrations in the leaf of both Aurora and Melle rose by 65–70 g/kg throughout the photoperiod, suggesting that differences in the total WSC concentration of these cultivars were not due to any increase in the amount of carbon fixed by Aurora but rather due to differences in the allocation of carbon during growth and development. This experiment demonstrated that tetraploidy was not beneficial in improving the WSC concentration of perennial ryegrass when imposed on two diploid cultivars which had the genetic potential for increased WSC accumulation. However, tetraploidy significantly increased the WSC concentration and by implication the nutritive value of a cultivar derived from a perennial ryegrass cultivar with standard WSC concentrations.
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Hassan, Jahidul, Ikuo Miyajima, Yukio Ozaki, Yuki Mizunoe, Kaori Sakai e Wasimullah Zaland. "Tetraploid Induction by Colchicine Treatment and Crossing with a Diploid Reveals Less-Seeded Fruit Production in Pointed Gourd (Trichosanthes dioica Roxb.)". Plants 9, n.º 3 (17 de março de 2020): 370. http://dx.doi.org/10.3390/plants9030370.
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Pointed gourd (Trichosanthes dioica Roxb.) (2n = 2x = 22) is a dioecious cucurbit vegetable and green fruit that is edible after cooking. Consumers prefer to consume seedless or less-seeded fruit because seeds are unpalatable due to their hard coats. Therefore, the cross compatibility between the diploid and induced tetraploid will be helpful for seedless or less-seeded fruit production. Thus, the present study was conducted using mature seeds that were immersed in 0.05%, 0.1%, and 0.5% colchicine for 24, 48, and 72 h to induce tetraploids. These tetraploids were used as parents (male or female) in the inter-ploidy and intra-ploidy crosses. A flow cytometric analysis confirmed the induction of three tetraploids at 0.5% colchicine for 48 and 72 h soaking periods. Among these, two (2) females and one (1) male were differentiated after flower initiation. Crossing between the tetraploid’s maternal and diploid paternal parent (4x × 2x), which were revealed to be compatible, resulted in a similar fruit set rate and shape as those of the diploid. In addition, a seed number of 4x × 2x produced fruits that were drastically reduced to 1.8 seeds per fruit, whereas the natural diploid fruits had 26.4 seeds per fruit. These findings suggest that colchicine-induced tetraploid females are important genetic resources for less-seeded fruit production. The genetic stability of tetraploid clones can easily and effectively be maintained by vine cutting for advanced uses.
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Mahony, MJ, SC Donnellan e JD Roberts. "An Electrophoretic Investigation of Relationships of Diploid and Tetraploid Species of Australian Desert Frogs Neobatrachus (Anura: Myobatrachidae)". Australian Journal of Zoology 44, n.º 6 (1996): 639. http://dx.doi.org/10.1071/zo9960639.
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Allozyme electrophoresis of 27 loci was used to characterise genetic variation among 29 populations of six diploid species of the myobatrachid frog genus Neobatrachus. All six species are well differentiated genetically with the percentage of fixed differences between species ranging from 11 to 59%. The genetic data are in agreement with the currently accepted species boundaries. The four tetraploid species were examined for 25 of the 27 loci assayed in the diploid species. In contrast to the diploid species, the tetraploid species shared electromorphs with each other at all the loci examined. The tetraploid species were examined for the presence of electromorphs specific to individual diploid species. The majority of these electromorphs were observed in the tetraploid species. For cases in which the range of a tetraploid species contacts that of a diploid species and the diploid population can be characterised by unique electromorphs, then evidence of current gene flow was found in the direction of the tetraploid populations. The data are compatible with single or multiple discrete or hybrid origins of the tetraploids overlain by gene flow among the tetraploids and between the tetraploids and some and perhaps all of the diploids by means of geographically limited but ongoing episodes of introgressive hybridisation.
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de Sousa, Joana Teixeira, Standish K. Allen, Brittany M. Wolfe e Jessica Moss Small. "Mitotic instability in triploid and tetraploid one-year-old eastern oyster, Crassostrea virginica, assessed by cytogenetic and flow cytometry techniques". Genome 61, n.º 2 (fevereiro de 2018): 79–89. http://dx.doi.org/10.1139/gen-2017-0173.
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For commercial oyster aquaculture, triploidy has significant advantages. To produce triploids, the principal technology uses diploid × tetraploid crosses. The development of tetraploid brood stock for this purpose has been successful, but as more is understood about tetraploids, it seems clear that chromosome instability is a principal feature in oysters. This paper is a continuation of work to investigate chromosome instability in polyploid Crassostrea virginica. We established families between tetraploids—apparently stable (non-mosaic) and unstable (mosaic)—and normal reference diploids, creating triploid groups, as well as tetraploids between mosaic and non-mosaic tetraploids. Chromosome loss was about the same for triploid juveniles produced from either mosaic or non-mosaic tetraploids or from either male or female tetraploids. However, there was a statistically significant difference in chromosome loss in tetraploid juveniles produced from mosaic versus non-mosaic parents, with mosaics producing more unstable progeny. These results confirm that chromosome instability, as manifested in mosaic tetraploids, is of little concern for producing triploids, but it is clearly problematic for tetraploid breeding. Concordance between the results from cytogenetics and flow cytometry was also tested for the first time in oysters, by assessing the ploidy of individuals using both techniques. Results between the two were non-concordant.
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Muthoni, Jane, Hussein Shimelis e Rob Melis. "Production of hybrid potatoes: Are heterozygosity and ploidy levels important?" Australian Journal of Crop Science, n.º 13(05) 2019 (20 de maio de 2019): 687–94. http://dx.doi.org/10.21475/ajcs.19.13.05.p1280.
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It has been proposed that maximizing heterosis for yield in potato may be achieved by maximizing heterozygosity and associated intra and interlocus interactions. Tetraploids offer more opportunities to create such interactions than diploids hence the general observations that tetraploids are higher yielding than diploids. Consequently, efforts have been made to increase heterozygosity in tetraploids by introgressing allelic diversity from other Solanum species into cultivated potato. However, conventional potato breeding is difficult because the cultivated potato is an autotetraploid with tetrasomic inheritance and it comprises highly heterozygous individuals which suffer inbreeding depression upon selfing; breeding at the tetraploid level is slow and less efficient than at diploid level. At the diploid level, it is possible to breed for and fix traits under recessive genetic control; it is nearly impossible to do so at the tetraploid level. There is also rapid response to selection due to greater variation in diploids than tetraploids. Consequently, there have been efforts to convert potato from an asexually propagated tetraploid crop into an inbred seed-propagated diploid; this is by production of inbred lines through selfing of the tetraploids to assemble desirable combinations of genes in the inbreds. These efforts are at the experimental stages and a lot of research needs to be done before they are confirmed. Because currently there is little experimental evidence to support superiority of the inbred seed-propagated diploid strategy, it appears the theory that heterosis for yield in potato may be achieved by maximizing heterozygosity and associated intra and interlocus interactions remain unchallenged; these interactions are more in tetraplods than in diploids. This paper therefore looks at genetic basis of yield heterosis in cultivated potato and the role of heterozygosity and ploidy level in production of hybrid potatoes.
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Rustidja, Rustidja. "ANALISA JUMLAH KROMOSOM IKAN MAS KOKI (Carrasius auratus) TETRAPLOID YANG DIHASILKAN DENGAN METODE KEJUTAN PANAS". Jurnal Perikanan Universitas Gadjah Mada 6, n.º 1 (1 de fevereiro de 2004): 1. http://dx.doi.org/10.22146/jfs.9037.
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The objectives of research was to analyses the chromosome numbers of tetraploid goldfish (Carassius auratus) produced by heat shocking method. The tetraploidy was carried out 29 minutes after fertilization of eggs by heat shocking for 1.5 minutes at 400C.The chromosome number was analyzed with the modus of chromosomes.The results indicated that 1) the diploid control of goldfish has 100.28% + 0.0982 chromosom with modus numbers of 100, and the tetraploid goldfish has 199.94 + 0.982 chromosomes with number of modus at 200. 2) The effectiveness of the heat shocking method in goldfish for tetraploidy was 46.60%.The hatching rate of diploid control (65.068% + 0.52%) was significantly diferent with that of tetraploid fish (24.53% + 1.649%). In addition, the survival rate of diploid controls (86.875% + 6.287). was significantly different with that of tetraploid goldfish (34.274% + 19.289%) and the specific growth rates of diploid controls (5,104 + 0,074) was not significantly diferent that of with tetraploid fish (3.982 + 0.011).
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Vittoria, Marc A., Elizabeth M. Shenk, Kevin P. O’Rourke, Amanda F. Bolgioni, Sanghee Lim, Victoria Kacprzak, Ryan J. Quinton e Neil J. Ganem. "A genome-wide microRNA screen identifies regulators of tetraploid cell proliferation". Molecular Biology of the Cell 29, n.º 14 (15 de julho de 2018): 1682–92. http://dx.doi.org/10.1091/mbc.e18-02-0141.
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Tetraploid cells, which are most commonly generated by errors in cell division, are genomically unstable and have been shown to promote tumorigenesis. Recent genomic studies have estimated that ∼40% of all solid tumors have undergone a genome-doubling event during their evolution, suggesting a significant role for tetraploidy in driving the development of human cancers. To safeguard against the deleterious effects of tetraploidy, nontransformed cells that fail mitosis and become tetraploid activate both the Hippo and p53 tumor suppressor pathways to restrain further proliferation. Tetraploid cells must therefore overcome these antiproliferative barriers to ultimately drive tumor development. However, the genetic routes through which spontaneously arising tetraploid cells adapt to regain proliferative capacity remain poorly characterized. Here, we conducted a comprehensive gain-of-function genome-wide screen to identify microRNAs (miRNAs) that are sufficient to promote the proliferation of tetraploid cells. Our screen identified 23 miRNAs whose overexpression significantly promotes tetraploid proliferation. The vast majority of these miRNAs facilitate tetraploid growth by enhancing mitogenic signaling pathways (e.g., miR-191-3p); however, we also identified several miRNAs that impair the p53/p21 pathway (e.g., miR-523-3p), and a single miRNA (miR-24-3p) that potently inactivates the Hippo pathway via down-regulation of the tumor suppressor gene NF2. Collectively, our data reveal several avenues through which tetraploid cells may regain the proliferative capacity necessary to drive tumorigenesis.
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Kim, Hyung-Eun, Jong-Eun Han, Hyoshin Lee, Ji-Hye Kim, Hyun-Hee Kim, Ki-Yong Lee, Jae-Heyuk Shin, Hyun-Kuy Kim e So-Young Park. "Tetraploidization Increases the Contents of Functional Metabolites in Cnidium officinale". Agronomy 11, n.º 8 (5 de agosto de 2021): 1561. http://dx.doi.org/10.3390/agronomy11081561.
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Cnidium officinale is an important medicinal crop grown in Asia for its pharmacological properties. In this study, tetraploid breeding was conducted to increases the content of medicinal compound and tolerance to the environmental conditions using in vitro shoot culture of C. officinale. For this, we generated tetraploid C. officinale plants using oryzalin, a chromosome doubling agent, and compared the morphological traits, cytological characteristics, and heat stress-responsive gene expression levels between tetraploid and diploid genotypes. Chromosome doubling efficiency was the highest in plantlets treated with 4.0 mg∙L−1 oryzalin for 2 days. Compared with diploids, the plant height of tetraploids was reduced, while the petiole diameter was increased by approximately 39%. The dry matter of tetraploid leaves was significantly higher than that of diploid leaves. Compared with diploids, tetraploids showed higher chloroplast number and stomatal complex size but lower chlorophyll and carotenoid contents. The phenolic content of tetraploid plantlets was significantly higher than that of diploid plantlets. Contents of naringin as well as salicylic acid and gentisic acid, which are strong antioxidant compounds, were dramatically increased upon tetraploidization. Interestingly, liquid chromatography–mass spectrometry (LC–MS) analyses revealed increased levels of senkyunolide F and phthalide in tetraploid roots but not in tetraploid or diploid leaves.
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Mori, Shiro, Masaki Yahata, Ayano Kuwahara, Yurina Shirono, Yasufumi Ueno, Misaki Hatanaka, Yoshimi Honda et al. "Morphological Characterization of Tetraploids of Limonium sinuatum (L.) Mill. Produced by Oryzalin Treatment of Seeds". Horticulturae 7, n.º 8 (15 de agosto de 2021): 248. http://dx.doi.org/10.3390/horticulturae7080248.
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Limonium sinuatum (L.) Mill. (2n = 2x = 16) is a popular ornamental plant with dimorphism of pollen grains (type A and type B) and stigmas (papilla and cob-like). We applied polyploidy breeding to this species in order to introduce desirable traits. Tetraploid and mixoploid L. sinuatum plants were successfully obtained with oryzalin treatment of L. sinuatum ‘Early Blue’ seeds. All three tetraploids had increased leaf width, stomatal size, flower length, and pollen width compared to those of the diploid, and tetraploids had four germinal pores of pollen grains, whereas the diploid had three. All tetraploids had type A pollen grains and cob-like stigmas. Furthermore, the growth of cultivated tetraploid plants was slow, with later bolting and flowering times. Mixoploids Mixo-1 and Mixo-3 were estimated to be polyploidy periclinal chimeric plants consisting of a tetraploid L1 layer and diploid L2 layer, and Mixo-2 was estimated to be a polyploidy periclinal chimeric plant consisting of the diploid L1 layer and tetraploid L2 layer. Mixo-4 had tetraploid L1 and L2 layers. Mixoploids, except Mixo-4, had type A pollen grains and cob-like stigmas, whereas Mixo-4 had type B pollen grains and papilla stigmas. These polyploids will be useful as polyploidy breeding materials.
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Zhang, Xingping, e Billy B. Rhodes. "A TISSUE CULTURE APPROACH FOR DEVELOPING TETRAPLOID WATERMELONS". HortScience 31, n.º 5 (setembro de 1996): 747b—747. http://dx.doi.org/10.21273/hortsci.31.5.747b.
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Tetraploids are needed to synthesize triploid watermelons, which produce “seedless” fruit with improved quality. Traditionally, the tetraploids are induced by applying colchicine to the growing apex of seedlings or soaking the seeds with colchicine solution. This method often produces low frequency of tetraploids and high frequency of chimeras. Breeding tetraploids takes much longer time than breeding diploids because of the low female fertility. We developed a tissue culture approach that allows breeders to develop desirable tetraploids with commercially acceptable volume of seed in 2 years. This tissue culture approach includes: 1) regenerate plants via shoot organogenesis from cotyledon tissue; 2) screen tetraploids based on leaf morphology (more serrated leaf margin and wider leaf shape) before transplanting, and confirm tetraploids based on pollen morphology (larger pollen with four copi) and/or seed characteristics; 3) self-pollinate tetraploids or cross the tetraploids with diploids to accurately estimate the female fertility; 4) micropropagate the best tetraploid(s) using axillary buds during the off-season; and 5) produce tetraploid seed from the cloned tetraploids in an isolation plot and evaluate the triploids derived from the tetraploid(s) in the following season. This approach has been practiced on more than 20 genotypes over the past 4 years.
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Sudo, Miki, Kiichi Yasuda, Masaki Yahata, Mai Sato, Akiyoshi Tominaga, Hiroo Mukai, Gang Ma, Masaya Kato e Hisato Kunitake. "Morphological Characteristics, Fruit Qualities and Evaluation of Reproductive Functions in Autotetraploid Satsuma Mandarin (Citrus unshiu Marcow.)". Agronomy 11, n.º 12 (29 de novembro de 2021): 2441. http://dx.doi.org/10.3390/agronomy11122441.
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The morphological characteristics and fruit quality of an autotetraploid plant selected from nucellar seedlings of Satsuma mandarin (Citrus unshiu Marcow.) were investigated. Additionally, in order to evaluate the reproductive potential of male and female gametes of the tetraploid Satsuma mandarin, reciprocal crosses with diploid cultivars were also carried out. The tetraploid had significantly thick and round leaves, as compared to those of the diploid Satsuma mandarin. The sizes of the flowers and pollen grains of the tetraploid were significantly larger than those of the diploid. Pollen fertility of tetraploid was high compared with that of the diploid. The tetraploid produced seedless fruits. The fruit weight of the tetraploid was equal to that of the diploid. Compared to the diploid fruits, the tetraploid fruit had less sugar contents and more organic acid contents. Although the tetraploid fruits showed similar traits to other Citrus tetraploids such as thick and hard peels, the tetraploid had a higher content of carotenoids in the flavedo than the diploid, and the rind color of the tetraploid was much better. In the reciprocal crosses between the tetraploid Satsuma mandarin and diploid cultivars, some seeds were obtained, and triploid progenies were obtained in all cross combinations.
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Adabiyah, Rifatul, Diah Ratnadewi, Tri Muji Ermayanti, Erwin Al Hafiizh e Elsa May Susanti. "Morphological and Anatomical Comparison between Tetraploid Stevia rebaudiana (Bertoni) Bertoni and its Parental Diploid". HAYATI Journal of Biosciences 30, n.º 2 (9 de dezembro de 2022): 321–35. http://dx.doi.org/10.4308/hjb.30.2.321-335.
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Stevia rebaudiana (Bertoni) Bertoni is a perennial herbaceous plant that produces natural low glycemic-index sweeteners alternative to sugar cane. The genetic improvement of Stevia needs to be investigated to increase its productivity. Although this plant has a narrow genetic diversity, genetic improvement through polyploidization may succeed. Meanwhile, genotypic characters of tetraploid Stevia were previously reported. This study then observed the phenotypic characters of the tetraploid plants, which aimed to evaluate the morphological and anatomical characteristics of tetraploid Stevia clones compared to its wild-type parental diploid plant. Three tetraploids and one diploid clone were grown in the field for 12 weeks. The results of qualitative descriptive characters showed that the tetraploid clones B60.3H8, P1T22 and P3T5 had habitus type, shoot bud shape, leaf margin, leaf venation, shape, and type of stem, type of flower, and seed similar to the diploid parental clone. However, the quantitative characters showed that the tetraploid clones had leaf size, stem diameter, root size, length of the single flower, length of the flower stalk, and length of fruit which were more extensive than those of the parental diploid clone. The leaf color of tetraploids was a darker green, and the range of initial flowering times was earlier. This finding gives more understanding of the phenotypic and anatomical characteristics of Stevia tetraploids compared to their parental diploid plant.
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Benabdelmouna, Abdellah, e Christophe Ledu. "Autotetraploid Pacific oysters (Crassostrea gigas) obtained using normal diploid eggs: induction and impact on cytogenetic stability". Genome 58, n.º 7 (julho de 2015): 333–48. http://dx.doi.org/10.1139/gen-2015-0014.
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We describe two methods of producing viable and fertile autotetraploid Pacific oyster (Crassostrea gigas Thunberg) based on the use of normal-sized oocytes produced by normal diploid females. Our methods showed that the oocyte size is not a limiting factor for the success of the induction to autotetraploidy. These methods offer means of direct introgression of genetic progress from elite diploid lines to tetraploids used as broodstock, avoiding a triploid step with the risk of transferring undesirable traits from highly fecund triploids. High variability in the level of cytogenetic stability was found among the different tetraploid oysters tested, showing that induction method has an important impact on the long-term cytogenetic stability of the tetraploids. It appears that induction method based on the use of triploid females induces a greater cytogenetic instability among tetraploids so obtained, and this compared to tetraploids originating from the two methods described in our present study. As the aneuploidies and reversions observed in tetraploids can have serious consequences for the sustainability of tetraploid broodstock itself, as well as their triploid offspring, the two tetraploid induction methods described in the present work offer means to produce tetraploids with optimal cytogenetic, genetic, and zootechnical performances.
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Sakhanokho, Hamidou F., e M. Nurul Islam-Faridi. "Spontaneous Autotetraploidy and Its Impact on Morphological Traits and Pollen Viability in Solanum aethiopicum". HortScience 49, n.º 8 (agosto de 2014): 997–1002. http://dx.doi.org/10.21273/hortsci.49.8.997.
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We report for the first time the incidence of spontaneous autotetraploidy in Solanum aethiopicum (PI 636107). Stomatal dimensions and frequency, number of chloroplasts per guard cell, flow cytometry, and chromosome counts were used to differentiate the diploid plants from tetraploids. The impact of increased ploidy on pollen viability as assessed by in vitro germination and on selected morphological traits was evaluated. In vitro pollen germination was reduced in tetraploid plants, but no significant differences were found in fruit production per plant between diploid and tetraploid plants. Compared with the diploids, the tetraploid plants were significantly shorter and had wider leaves and smaller fruits; therefore, tetraploid S. aethiopicum plants can be valuable for future breeding programs, particularly those aiming to develop shorter, more compact plants. Moreover, some S. aethiopicum selections are grown for their edible leaves, so tetraploid plants producing large leaves would be desirable. Additionally, the availability of tetraploid S. aethiopicum could remove hybridization barriers caused by ploidy differences with other tetraploid Solanum species.
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Norden, Elliot H., Paul M. Lyrene e Jose X. Chaparro. "Ploidy, Fertility, and Phenotypes of F1 Hybrids between Tetraploid Highbush Blueberry Cultivars and Diploid Vaccinium elliottii". HortScience 55, n.º 3 (março de 2020): 281–86. http://dx.doi.org/10.21273/hortsci14597-19.
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A progeny of 55 blueberry seedlings produced by pollinating 4301 flowers of tetraploid highbush blueberry cultivars with pollen from 19 different diploid Vaccinium elliottii plants was studied to determine hybridity and ploidy. Of the 21 seedlings whose phenotypes were intermediate between parental types, indicating hybridity, 18 were triploid and three were tetraploid. Pollen of the triploids, when viewed at ×250, was almost all shrunken and aborted, although some triploid hybrids produced a few large, plump microspores in dyads or monads. Triploids produced no seed when pollinated with pollen from 4x highbush or 2x V. elliottii or when open-pollinated outside the greenhouse in the presence of fertile diploid and tetraploid blueberries. Tetraploid hybrids produced large populations of vigorous seedlings when intercrossed. Both triploid and tetraploid F1 hybrids were intermediate between the parents in leaf size and flower size. The triploids produced no berries; the tetraploids were intermediate between the parents in berry size but averaged lower in Brix and berry firmness than either parent. Seven additional F1 hybrids from reciprocal crosses were obtained by pollinating 2309 flowers of 2x V. elliottii with pollen from tetraploid highbush cultivars. Although five V. elliottii clones served as female parents in these crosses, only one produced any seedlings. Six of the seven hybrids flowered and were fertile tetraploids; one was a sterile triploid.
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Chen, Li-ping, Yan-ju Wang e Man Zhao. "In vitro Induction and Characterization of Tetraploid Lychnis senno Siebold et Zucc." HortScience 41, n.º 3 (junho de 2006): 759–61. http://dx.doi.org/10.21273/hortsci.41.3.759.
Texto completo da fonteResumo:
In this study, in vitro induction of tetraploid Lychnis senno Siebold et Zucc. and its cytological and morphological characterization were conducted. For polyploid induction, nodal segments with axillary buds from in vitro grown plants were kept for 3 days in MS (Murashige and Skoog, 1962) liquid or solid media added with a series of concentrations of colchicine. Out of total 588 recovered plants, 15 tetraploids and 6 mixoploids determined by flow cytometry analysis were obtained. The tetraploid contained 48 chromosomes, twice the normal diploid number of 24, as observed under light microscope. The tetraploid plants exhibited much larger but less stomata than diploid plants. Moreover, significant differences in stem height and leaf size between the diploid and tetraploid plants were noted. The tetraploid plants were more compact than diploids.
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Charpentier, A., M. Feldman e Y. Cauderon. "Genetic control of meiotic chromosome pairing in tetraploid Agropyron elongatum. I. Pattern of pairing in natural and induced tetraploids and in F1 triploid hybrids". Canadian Journal of Genetics and Cytology 28, n.º 5 (1 de outubro de 1986): 783–88. http://dx.doi.org/10.1139/g86-110.
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Meiotic chromosome pairing was studied in natural and induced tetraploid Agropyron elongatum, as well as in triploid hybrids between natural tetraploid and diploid cytotypes. The natural tetraploids showed a highly regular, diploid-like pairing, while the induced ones showed an average of two to three multivalents per cell. A high level of pairing was exhibited by the triploid hybrids, 4.15 bivalents and 2.82 trivalents per cell, supporting the assumption that the natural tetraploid is of an autoploid origin. Frequencies of meiotic configurations of the induced tetraploid and of the F1 triploid hybrids deviated significantly from the expected values based on a model assuming random pairing within one homologous group in autoploids: the observed data were characterized by fewer multivalents than expected, indicating a tendency towards bivalentization. This tendency is fully realized in the natural tetraploid. The presence of a pairing-control system in these autoploids, most probably a genetic one, that determines bivalent rather than multivalent pairing is suggested.Key words: Agropyron, pairing, bivalentization, tetraploid, multivalents.
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Dabkevičienė, Giedrė, Vilma Kemešytė, Gražina Statkevičiūtė, Nijolė Lemežienė e Gintaras Brazauskas. "Autopolyploids in fodder grass breeding: induction and field performance". Spanish Journal of Agricultural Research 15, n.º 4 (7 de fevereiro de 2018): e0706. http://dx.doi.org/10.5424/sjar/2017154-11357.
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Doubling of chromosome set directly affects plant performance through increase of organ size, higher feeding value and increased resistance to adverse environmental factors. Therefore efficient methods of polyploid induction are needed in order to develop new varieties of naturally diploid fodder grass species. The efficiency of antimitotic agents as colchicine, amiprophos-methyl, trifluralin and oryzalin was compared in a series of tetraploid induction experiments in Lolium multiflorum, L. perenne and Festuca pratensis, while newly developed tetraploid plants were compared to standard tetraploid varieties in the field trials. Colchicine treatment proved to be the most efficient method for in vitro cultured embryos in comparison with the other agents. Induced tetraploids of F. pratensis produced higher dry matter and seed yield and could be used for the development of new varieties. Induced tetraploid plants of Lolium spp. were equal to the standard varieties in field trials, therefore they could be used as parental genotypes in crosses. Induced tetraploids of F. pratensis produced higher dry matter and seed yield and could be used for development of new variety.
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Fetouh, Mohammed I., Abdul Kareem, Gary W. Knox, Sandra B. Wilson e Zhanao Deng. "Induction, Identification, and Characterization of Tetraploids in Japanese Privet (Ligustrum japonicum)". HortScience 51, n.º 11 (novembro de 2016): 1371–77. http://dx.doi.org/10.21273/hortsci11138-16.
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A number of privet species (Ligustrum spp.) that are important to the nursery and landscape industry have escaped cultivation and become invasive or weedy in the United States and other countries. Induced tetraploids in these species may produce new selections or cultivars with reduced or eliminated invasive potential. Applying drops of semisolid agar containing 0.1% to 0.3% colchicine and 0.2% dimethyl sulfoxide (DMSO) to newly emerged seedlings of japanese privet (Ligustrum japonicum Thunb.) resulted in 15.6% to 22.6% tetraploid induction. The nuclear DNA content of tetraploids was 5.31 pg/2C, 101.9% higher than that of diploids. Compared with diploid plants, tetraploids were more compact, with an average of 31.0% shorter plant height and 33.1% smaller canopy width. Tetraploids had 29.2% thicker internodes, and their leaves were 39.5% larger and 33.8% thicker, resulting in 42.1% to 24.1% greater fresh or dry leaf weights (per leaf) in tetraploids compared with diploids. Without indole-3-butyric acid (IBA) treatment, cuttings from tetraploids showed 28% lower rooting than diploids. IBA treatments improved the rooting of tetraploid cuttings, resulting in 65% rooting success. These results indicate that tetraploids can be readily induced in japanese privet and induced tetraploids show significant changes in plant growth and size, shoot growth, leaf morphology, and rooting of cuttings. The modified tetraploid induction method and the induced tetraploids are expected to be useful for producing new selections or cultivars with reduced invasive potential in japanese and other privets.
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Correia, Sandra, Ana Braga, João Martins, Barbara Correia, Glória Pinto e Jorge Canhoto. "Effects of Polyploidy on Physiological Performance of Acclimatized Solanum betaceum Cav. Plants under Water Deficit". Forests 14, n.º 2 (21 de janeiro de 2023): 208. http://dx.doi.org/10.3390/f14020208.
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The urgent need to identify stress-tolerant genotypes and understand their inherent genetic plasticity is one of the major targets of research and breeding programs. Species that are cultivated in areas that are prone to drought need to be able to tolerate water stress (WS) while still displaying features that are economically valuable. Tamarillo (Solanum betaceum) is a solanaceous fruit crop with increasing agronomic interest due to the nutritional properties of its edible fruits and its biotechnological potential. Several protocols have been established for the in vitro culture of this species and controlled hybridization, as well as for the induction of tetraploidy. Nevertheless, the impact of WS on S. betaceum performance has been poorly studied, and nothing is known about the role of ploidy status on this response. Since no morphological differences were noticed between diploids and tetraploids at the end of the acclimatization period, we hypothesized that ploidy level may have a role in plant drought responses. Thus, micropropagated and acclimatized tamarillo diploid (2n = 2x = 24) and tetraploid (4n = 4x = 48) plants were exposed to WS, and several physiological parameters were evaluated, such as plant growth, water potential, photosynthetic performance, sugars, proline, and MDA levels. Water stress did not affect plant growth in both diploids and tetraploids, but it induced stomatal closure and reduced the net CO2 assimilation rate. Water stress also reduced the photosynthetic efficiency of PSII, but no differences were found in the total chlorophyll content. From all the parameters analyzed, tetraploid plants showed a better response under water shortage conditions when considering water potential (WP). Metabolite analysis indicated no significant differences in the accumulation of soluble sugars and MDA in WS plants but a significant increase in proline accumulation in diploids exposed to WS. These observed differences in parameters such as WP and proline accumulation point to mechanisms of osmoregulation and stress signaling that differ between diploid and tetraploid plants, particularly in WS conditions, demonstrating that tetraploids can adapt better to water shortage conditions than their diploid counterparts.
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Hu, Qianni, e Genlou Sun. "Phylogenetic analysis of two single-copy nuclear genes revealed origin and complex relationships of polyploid species of Hordeum in Triticeae (Poaceae)". Genome 60, n.º 6 (junho de 2017): 518–29. http://dx.doi.org/10.1139/gen-2016-0179.
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Two single-copy nuclear genes, the second largest subunit of RNA polymerase II (RPB2) and thioredoxin-like gene (HTL), were used to explore the phylogeny and origin of polyploid species in Hordeum. Our results were partly in accord with previous studies, but disclosed additional complexity. Both RPB2 and HTL trees confirmed the presence of Xa genome in H. capense and H. secalinum, and that H. depressum originated from H. californicum together with other American diploids, either H. intercedens or H. pusillum. American diploids solely contributed to the origin of H. depressum. The Asian diploids, either H. bogdanii or H. brevisubulatum, contributed to the formation of American polyploids except H. depressum. RPB2 and HTL sequences showed that H. roshevitzii did not contribute to the origin of American tetraploids. Our data showed a close relationship between the hexaploids H. procerum and H. parodii and the tetraploids H. brachyantherum, H. fuegianum, H. guatemalense, H. jubatum, and H. tetraploidum. The involvement of the diploid H. pusillum and the tetraploid H. jubatum in the formation of H. arizonicum was also indicated in the HTL phylogeny. Our results suggested a possible gene introgression of W- and P-genome species into the tetraploid H. jubatum and the hexaploid H. procerum.
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Wang, Kang, Linchi He, Honglang Yan e Xiaoyun Wei. "Induction of tetraploidity with antimicrotubule agents in oriental melon (Cucumis melo var. Makuwa)". Israel Journal of Plant Sciences 62, n.º 3 (18 de maio de 2015): 198–207. http://dx.doi.org/10.1080/07929978.2015.1067411.
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Polyploidy induction is an important method for the innovation of germplasm resources because polyploid plants have superior characteristics to diploid ones. In this paper, oriental melon (Cucumis melovar. makuwa) tetraploids were induced by treating the apical meristem of seedlings with oryzalin, amiprophos-methyl (APM) and colchicine. The results showed that each of these three antimicrotubule agents could induce the formation of tetraploid oriental melon, but oryzalin and APM showed higher efficiencies of tetraploid induction. The efficiencies of tetraploid induction were highest (14.44%) when treated with 80 µmol·L−1APM for 6 days. Stomata characteristics were used to screen the treated plants for changes in ploid levels preliminarily. Subsequently, the changes in ploid levels were further confirmed by flow-cytometric analysis and chromosome counts of root tip cells. The comparison between diploids and tetraploids in fruit characteristics, reproductive characteristics, and postharvest storage qualities showed that the fruit of tetraploids had thicker flesh, higher total soluble solid (TSS) content and lower fruit shape index than diploids. The pollen grains of tetraploids were larger but showed lower vitality. In addition, a higher percentage of embryo-deficient seeds contributed to lower fertility. During postharvest storage, the fruit of tetraploids softened faster, had higher TSS content and lower respiration rate.
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Baldwin, Sarah J., e Brian C. Husband. "Genome duplication and the evolution of conspecific pollen precedence". Proceedings of the Royal Society B: Biological Sciences 278, n.º 1714 (dezembro de 2010): 2011–17. http://dx.doi.org/10.1098/rspb.2010.2208.
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Conspecific pollen precedence can be a strong reproductive barrier between polyploid and diploid species, but the role of genome multiplication in the evolution of this barrier has not been investigated. Here, we examine the direct effect of genome duplication on the evolution of pollen siring success in tetraploid Chamerion angustifolium . To separate the effects of genome duplication from selection after duplication, we compared pollen siring success of synthesized tetraploids (neotetraploids) with that of naturally occurring tetraploids by applying 2 x , 4 x (neo or established) or 2 x + 4 x pollen to diploid and tetraploid flowers. Seed set increased in diploids and decreased in both types of tetraploids as the proportion of pollen from diploid plants increased. Based on offspring ploidy from mixed-ploidy pollinations, pollen of the maternal ploidy always sired the majority of offspring but was strongest in established tetraploids and weakest in neotetraploids. Pollen from established tetraploids had significantly higher siring rates than neotetraploids when deposited on diploid (4 x est = 47.2%, 4 x neo = 27.1%) and on tetraploid recipients (4 x est = 91.9%, 4 x neo = 56.0%). Siring success of established tetraploids exceeded that of neotetraploids despite having similar pollen production per anther and pollen diameter. Our results suggest that, while pollen precedence can arise in association with the duplication event, the strength of polyploid siring success evolves after the duplication event.
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Mohammadi, Mohsen, Behzad Kaviani e Shahram Sedaghathoor. "In vivo polyploidy induction of Phalaenopsis amabilis in a bubble bioreactor system using colchicine". Ornamental Horticulture 27, n.º 2 (junho de 2021): 204–12. http://dx.doi.org/10.1590/2447-536x.v27i2.2275.
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Abstract Phalaenopsis amabilis Blume var. grandiflora Bateman is economically important as cut and pot flower. Polyploidy is considered as a valuable tool in improvement and evolution of ornamental plants. Protocorm-like bodies (PLBs) of P. amabilis were cultured on Murashige and Skoog medium containing 0.20 mg L-1 IBA together with 2.00 mg L-1 KIN and 1.00 g L-1 activated charcoal and grown for a period of five months. Fully-developed plantlets from in vitro grown PLBs were immersed in a bubble reactor filled with half-strength Hoagland solution containing the antimitotic agent colchicine (0.05%, 0.10% and 0.15%, w/v) for 72 h with a few drops (1 mL of 0.1%) of octylphenoxypolyethoxyethanol or Nonidet (P-40) as a surfactant. Plantlets were aerated to prevent hypoxia. Colchicine-treated and untreated plantlets were transferred to pots for a period of 60 days. Tetraploidy was successfully induced by 0.15% colchicine. Polyploidy levels were firstly detected using flow cytometry and then confirmed by cytological and morphological observations. The chromosome number was 2n = 2x = 38 in diploids and 2n = 4x = 76 in tetraploid. Incubation of plantlets in liquid medium containing 0.15% colchicine induced the maximum recovered tetraploids with minimum frequency of survival (50%). The tetraploid plants were more compact and exhibited round and thick leaves with darker green color than diploids. Stomata size in tetraploids were larger with less density than diploids. Chloroplast number in guard cells of tetraploids was about two times more than that of control. These results indicate that induction of tetraploids are a reliable and powerful tool for generation of novel phenotypes with ornamental and horticultural value for genetic improvement and breeding. Produced tetraploids in current study have potential in the ornamental/floriculture trade.
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Galofré, Claudia, Öykü Gönül Geyik, Elena Asensio, Darawalee Wangsa, Daniela Hirsch, Carolina Parra, Jordi Saez et al. "Tetraploidy-Associated Genetic Heterogeneity Confers Chemo-Radiotherapy Resistance to Colorectal Cancer Cells". Cancers 12, n.º 5 (30 de abril de 2020): 1118. http://dx.doi.org/10.3390/cancers12051118.
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Tetraploidy, or whole-genome duplication, is a common phenomenon in cancer and preludes chromosome instability, which strongly correlates with disease progression, metastasis, and treatment failure. Therefore, it is reasonable to hypothesize that tetraploidization confers multidrug resistance. Nevertheless, the contribution of whole-genome duplication to chemo-radiotherapy resistance remains unclear. Here, using isogenic diploid and near-tetraploid clones from three colorectal cancer cell lines and one non-transformed human epithelial cell line, we show a consistent growth impairment but a divergent tumorigenic potential of near-tetraploid cells. Next, we assessed the effects of first-line chemotherapeutic drugs, other commonly used agents and ionizing radiation, and found that whole-genome duplication promoted increased chemotherapy resistance and also conferred protection against irradiation. When testing the activation of apoptosis, we observed that tetraploid cells were less prone to caspase 3 activation after treatment with first-line chemotherapeutic agents. Furthermore, we found that pre-treatment with ataxia telangiectasia and Rad3 related (ATR) inhibitors, which targets response to replication stress, significantly enhanced the sensitivity of tetraploid cells to first-line chemotherapeutic agents as well as to ionizing radiation. Our findings provide further insight into how tetraploidy results in greater levels of tolerance to chemo-radiotherapeutic agents and, moreover, we show that ATR inhibitors can sensitize near-tetraploid cells to commonly used chemo-radiotherapy regimens.
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Jenkins, G., J. White e J. S. Parker. "Elimination of multivalents during meiotic prophase in Scilla autumnalis. II. Tetraploid". Genome 30, n.º 6 (1 de dezembro de 1988): 940–46. http://dx.doi.org/10.1139/g88-150.
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The pairing behaviour of chromosomes during meiotic prophase in two Scilla autumnalis tetraploids was investigated by observing synaptonemal complexes from serial sections and whole-mount surface spreads. In one of the tetraploids with the genomic constitution AAB7B7 pairing at first metaphase of meiosis is restricted to homologous chromosomes and only bivalents appear. In the second tetraploid, AB7B7B7, some multivalents are found at first metaphase, but most of the configurations are bivalent. The bivalents, however, result from chiasma formation between homoeologous as well as homologous chromosomes. Both tetraploids show extensive multivalent formation at zygotene. The transformation of these multivalents to bivalents is described and interpreted in the two tetraploid forms.Key words: Scilla autumnalis, synaptonemal complex, multivalents, elimination, polyploids.
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Wang, Wei, Qiang Tu, Rongrong Chen, Pincang Lv, Yanqing Xu, Qian Xie, Zhaojian Song, Yuchi He, Detian Cai e Xianhua Zhang. "Polyploidization Increases the Lipid Content and Improves the Nutritional Quality of Rice". Plants 11, n.º 1 (4 de janeiro de 2022): 132. http://dx.doi.org/10.3390/plants11010132.
Texto completo da fonteResumo:
Plant polyploidization is frequently associated with changes in nutrient contents. However, the possible contribution of metabolites to this change has not been investigated by characterizing the metabolite contents of diploid and tetraploid forms of rice (Oryza sativa L.). We compared the metabolites of a group of diploid–tetraploid japonica brown rice and a group of diploid–tetraploid indica brown rice based on liquid chromatography–tandem mass spectrometry. In total, 401 metabolites were identified; of these, between the two diploid–tetraploid groups, 180 showed opposite expression trends, but 221 showed the same trends (147 higher abundance vs. 74 lower abundance). Hierarchical cluster analysis of differential metabolites between diploid and tetraploid species showed a clear grouping pattern, in which the expression abundance of lipids, amino acids and derivatives, and phenolic acids increased in tetraploids. Further analysis revealed that the lipids in tetraploid rice increased significantly, especially unsaturated fatty acids and phospholipids. This study provides further basis for understanding the changes in rice nutritional quality following polyploidization and may serve as a new theoretical reference for breeding eutrophic or functional rice varieties via polyploidization.
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Syvertsen, J. P., J. W. Grosser e L. S. Lee. "590 Growth and Physiological Characteristics of Diploid and Tetraploid Citrus Rootstock Seedlings Grown at Elevated CO2". HortScience 34, n.º 3 (junho de 1999): 548D—548. http://dx.doi.org/10.21273/hortsci.34.3.548d.
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We grew three diploid (2X) Citrus rootstock seedlings and their autotetraploids (4X) at elevated CO2 to obtain insights into limitations on growth and net gas exchange that have been associated with tetraploidy. Well-nourished Volkamer lemon (Volk), Troyer citrange (Troy), and Cleopatra mandarin (Cleo) were grown in greenhouses at ambient or twice ambient CO2 for 3 months. We measured plant growth, water relations, mineral nutrition, and net gas exchange characteristics of leaves. Overall, tetraploid roots were thicker as 4X had lower root length: dry weight ratio or specific root length (SRL) than 2X roots. Tetraploid plants were smaller and had higher root/shoot ratios, shorter fibrous roots, and lower whole plant transpiration than 2X. Tetraploids also had lower leaf N and P concentrations on a dry weight basis. Since 4X leaves had thicker leaves (more dry weight per area) than 2X leaves, these nutrient differences disappeared when expressed on an leaf area basis. Elevated CO2 increased plant growth but decreased leaf N, P, and K apparently by a growth dilution effect. Elevated CO2 also increased fibrous root thickness, leaf thickness, and net assimilation of CO2 (ACO2) but decreased stomatal conductance and transpiration such that leaf water use efficiency increased. There was no effect of ploidy level on ACO2 but 4X Volk and Troy had lower rates of ACO2 than their diploids at elevated CO2. Hydraulic conductivity of intact root systems (measured in a pressure pot) was correlated to total plant growth but variability obscured effects of CO2 or ploidy on root conductivity. The low SRL of tetraploids were correlated with lower rates of water use and lower leaf nutrient concentrations, which may be operative in determining the growth characteristics associated with tetraploidy.
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Montgomery, Sarah M., Brandi Karisch, Jane A. Parish, Jesse Morrison e Brian Baldwin. "57 Effects of Diploid and Tetraploid Annual Ryegrass Cultivars on Cattle Performance, Herbage Mass, and Nutritive Value". Journal of Animal Science 98, Supplement_2 (1 de novembro de 2020): 20. http://dx.doi.org/10.1093/jas/skz397.044.
Texto completo da fonteResumo:
Abstract Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x) and tetraploid (2n = 4x). Polyploid versions of a given plant species result in increased seedling vigor, more robust growth and, potentially, greater yield. While most data suggest no difference in yield between diploid and tetraploid cultivars, there is still potential for weight gain advantages thanks to increased non-structural carbohydrates in tetraploid cells. The objectives of this study were to compare weight gain of cattle grazing either diploid or tetraploid cultivars of annual ryegrass. Two diploid annual ryegrass cultivars (Marshall and Tam 90) and two tetraploid cultivars (Jumbo and Nelson) were planted in 0.81-ha pastures, each replicated four times. Four steers (mean initial BW = 214 kg) were randomly assigned to each pasture for an 82-d grazing period. Body weights were recorded starting at d0 then every 28 days throughout the season. Data were analyzed in the GLM procedure of SAS using a significance level of α = 0.05. There were significant differences between cytotypes with respect to seasonal yield with diploids (9547.90 kg/ha) yielding greater than tetraploids (7762.00 kg/ha). As expected, ADF and NDF fractions were significantly less for tetraploids (ADF; 31.39%, NDF; 31.39%) compared to diploids (ADF; 33.75%, NDF; 53.25%). Tetraploids also contained significantly greater crude protein (13.50%) than diploids (12.90%). Cytotype had no effect on final average daily gain (ADG) (P = 0.9427). However, final ADG was significantly impacted by cultivar (P = 0.0134). Final ADG for Tam 90 (1.10 kg/d) was greater than Marshall (0.92 kg/d). Cattle grazing Nelson (1.04 kg/d) and Jumbo (0.99 kg/d) did not differ. Results show that regardless of differences in seasonal yield and nutritive value between cytotypes, there were no advantages in ADG for cattle grazing either cytotype.
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Montgomery, Sarah M., Brandi Karisch, Jane A. Parish, Jesse Morrison e Brian Baldwin. "58 Effects of Diploid and Tetraploid Annual Ryegrass Cultivars on Cattle Performance, Herbage Mass, and Nutritive Value". Journal of Animal Science 98, Supplement_2 (1 de novembro de 2020): 29. http://dx.doi.org/10.1093/jas/skz397.066.
Texto completo da fonteResumo:
Abstract Annual ryegrass (Lolium multiflorum Lam.) can be divided into two cytotypes: diploid (2n = 2x) and tetraploid (2n = 4x). Polyploid versions of a given plant species result in increased seedling vigor, more robust growth and, potentially, greater yield. While most data suggest no difference in yield between diploid and tetraploid cultivars, there is still potential for weight gain advantages thanks to increased non-structural carbohydrates in tetraploid cells. The objectives of this study were to compare weight gain of cattle grazing either diploid or tetraploid cultivars of annual ryegrass. Two diploid annual ryegrass cultivars (Marshall and Tam 90) and two tetraploid cultivars (Jumbo and Nelson) were planted in 0.81-ha pastures, each replicated four times. Four steers (mean initial BW = 214 kg) were randomly assigned to each pasture for an 82-d grazing period. Body weights were recorded starting at day 0 then every 28 days throughout the season. Data were analyzed in the GLM procedure of SAS using a significance level of α = 0.05. There were significant differences between cytotypes with respect to seasonal yield with diploids (9547.90 kg/ha) yielding greater than tetraploids (7762.00 kg/ha). As expected, ADF and NDF fractions were significantly less for tetraploids (ADF; 31.39%, NDF; 31.39%) compared to diploids (ADF; 33.75%, NDF; 53.25%). Tetraploids also contained significantly greater crude protein (13.50%) than diploids (12.90%). Cytotype had no effect on final average daily gain (ADG) (P = 0.9427). However, final ADG was significantly impacted by cultivar (P = 0.0134). Final ADG for Tam 90 (1.10 kg/d) was greater than Marshall (0.92 kg/d). Cattle grazing Nelson (1.04 kg/d) and Jumbo (0.99 kg/d) did not differ. Results show that regardless of differences in seasonal yield and nutritive value between cytotypes, there were no advantages in ADG for cattle grazing either cytotype.
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Compton, Michael E., J. W. Harris e D. J. Gray. "A Simple Method for Estimating Ploidy of in Vitro Watermelon Plantlets". HortScience 30, n.º 4 (julho de 1995): 752B—752. http://dx.doi.org/10.21273/hortsci.30.4.752b.
Texto completo da fonteResumo:
Ploidy of in vitro watermelon plantlets was estimated by painting the lower epidermis of leaves with fluorescein diacetate (FDA) and observing fluorescence of guard cell chloroplasts with a microscope and UV light. Leaves from shoot-tip cultures of known diploid and tetraploid cultivars were used to establish the mean number of chloroplasts per guard cell pair for in vitro plantlets. Leaves from diploid and tetraploid plantlets had 9.7 and 17.8 chloroplasts per guard cell pair, respectively. This method was used to estimate ploidy of shoots regenerated from cotyledon explants of the diploid cultivar Minilee. Approximately 10.6% of regenerated shoots were classified as tetraploid while still in vitro. Putative tetraploids were transplanted to the field and self-pollinated. A majority of polyploids identified in vitro were true breeding, nonchimeric tetraploids. This study demonstrate that FDA can be used to estimate ploidy of in vitro shoots of watermelon prior to acclimatization and transfer of plants to the greenhouse or field.
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Li, Meiya, Bin Ding, Weipeng Huang, Jieli Pan, Zhishan Ding e Fusheng Jiang. "Induction and Characterization of Tetraploids from Seeds of Bletilla striata (Thunb.) Reichb.f." BioMed Research International 2018 (2018): 1–8. http://dx.doi.org/10.1155/2018/3246398.
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Bletilla striata (Thunb.), an ornamental and medicinal plant, is on the list of endangered plants in China. Its pseudobulb is abundant in polysaccharide and has been used for centuries as a herbal remedy. However, a recent rise in demand has placed it at risk of extinction, and therefore, research on its propagation and genetic improvement is essential. Since polyploids tend to possess advantageous qualities, we incubated B. striata seeds with colchicine with the aim of creating tetraploid plantlets. Aseptic seeds treated with 0.1% colchicine for 7 days showed the highest tetraploid induction rate of 40.67 ± 0.89%. Compared with the wild-type, the tetraploids could be identified by their morphological characteristics including larger stomata at a lower density, larger leaf blades, and a thicker petiole. Contents of polysaccharide and phenolic compounds were also determined in the tetraploid pseudobulbs, revealing significantly higher values than in the wild-type. In vitro colchicine treatment can therefore be used to successfully produce B. striata tetraploids with superior pseudobulbs.
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Moncada, Pilar, e Susan McCouch. "Simple sequence repeat diversity in diploid and tetraploid Coffea species". Genome 47, n.º 3 (1 de junho de 2004): 501–9. http://dx.doi.org/10.1139/g03-129.
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Thirty-four fluorescently labeled microsatellite markers were used to assess genetic diversity in a set of 30 Coffea accessions from the CENICAFE germplasm bank in Colombia. The plant material included one sample per accession of seven East African accessions representing five diploid species and 23 wild and cultivated tetraploid accessions of Coffea arabica from Africa, Indonesia, and South America. More allelic diversity was detected among the five diploid species than among the 23 tetraploid genotypes. The diploid species averaged 3.6 alleles/locus and had an average polymorphism information content (PIC) value of 0.6, whereas the wild tetraploids averaged 2.5 alleles/locus and had an average PIC value of 0.3 and the cultivated tetraploids (C. arabica cultivars) averaged 1.9 alleles/locus and had an average PIC value of 0.22. Fifty-five percent of the alleles found in the wild tetraploids were not shared with cultivated C. arabica genotypes, supporting the idea that the wild tetraploid ancestors from Ethiopia could be used productively as a source of novel genetic variation to expand the gene pool of elite C. arabica germplasm.Key words: Coffea spp., microsatellite markers, genetic diversity.
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Adelberg, Jeffrey, B. B. Rhodes e Halina Skorupska. "GENERATING TETRAPLOID MELONS FROM TISSUE CULTURE". HortScience 25, n.º 9 (setembro de 1990): 1073c—1073. http://dx.doi.org/10.21273/hortsci.25.9.1073c.
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Watermelon (Citrullus Lanatus (Thunb.) Matsum and Nakai) and muskmelon (Cucumis melo) were regenerated from immature cotyledons cultured on MS medium containing 10 μM BA. Small population of watermelon and muskmelon regenerants contained tetraploids as variants. The tetraploid individuals were recognized by morphological features including enlarged leaves, tendrils, male flowers, and variable pollen grains. After self-pollination, seed lots reflected differences in size expected from tetraploid parents.. Cytological data from root tips of R1 populations will be presented.
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Longui, Eduardo Luiz, Guilherme Henrique Custódio, Erick Phelipe Amorim, Francides Gomes da Silva Júnior, Shinitiro Oda e Izabel Christina Gava Souza. "Differences in wood properties among Eucalyptus grandis and Eucalyptus grandis x Eucalyptus urophylla with different degrees of ploidy". Research, Society and Development 10, n.º 16 (14 de dezembro de 2021): e395101624035. http://dx.doi.org/10.33448/rsd-v10i16.24035.
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We compared the anatomy, density, chemical contents, and bioenergy values of Eucalyptus grandis and hybrids of Eucalyptus grandis x Eucalyptus urophylla wood originating from diploids, triploids and tetraploids. We hypothesize that Eucalyptus grandis and hybrids of Eucalyptus grandis x Eucalyptus urophylla with different degrees of ploidy have variations as a result of different sets of chromosomes producing different phenotypic expressions and chemical constituents, such as variation in cell size and frequency, which would directly influence wood quality. Twenty-year-old trees were cut, eight for each ploidy: diploids and tetraploids are E. grandis; triploids are E. grandis x E. urophylla. We use standardized techniques. Our hypothesis was confirmed. Triploid and tetraploid trees presented wider trunks, taller trees with longer stems and wider crowns compared to diploid trees. Wood density showed significant radial variation only in diploids, while triploid and tetraploid trees were more homogeneous. In polyploid trees, the anatomical features did not clearly present a radial pattern. Triploid and tetraploid trees presented higher density wood than diploid trees. The chemical constituents varied from pith to bark in the three ploidies, but no differences between ploidies were found. For energy generation purposes, diploid and triploid trees are more desirable than tetraploid trees.
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de Sousa, Joana Teixeira, Standish K. Allen, Haley Baker e Joseph L. Matt. "Aneuploid progeny of the American oyster, Crassostrea virginica, produced by tetraploid × diploid crosses: another example of chromosome instability in polyploid oysters". Genome 59, n.º 5 (maio de 2016): 327–38. http://dx.doi.org/10.1139/gen-2015-0222.
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The commercial production of triploids, and the creation of tetraploid broodstock to support it, has become an important technique in aquaculture of the eastern oyster, Crassostrea virginica. Tetraploids are produced by cytogenetic manipulation of embryos and have been shown to undergo chromosome loss (to become a mosaic) with unknown consequences for breeding. Our objective was to determine the extent of aneuploidy in triploid progeny produced from both mosaic and non-mosaic tetraploids. Six families of triploids were produced using a single diploid female and crossed with three mosaic and non-mosaic tetraploid male oysters. A second set of crosses was performed with the reciprocals. Chromosome counts of the resultant embryos were tallied at 2–4 cell stage and as 6-hour(h)-old embryos. A significant level of aneuploidy was observed in 6-h-old embryos. For crosses using tetraploid males, aneuploidy ranged from 53% to 77% of observed metaphases, compared to 36% in the diploid control. For crosses using tetraploid females, 51%–71% of metaphases were aneuploidy versus 53% in the diploid control. We conclude that somatic chromosome loss may be a regular feature of early development in triploids, and perhaps polyploid oysters in general. Other aspects of chromosome loss in polyploid oysters are also discussed.
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Smith, Tyler W., Charlotte Walinga, Song Wang, Paul Kron, Jan Suda e Juan Zalapa. "Evaluating the relationship between diploid and tetraploid Vaccinium oxycoccos (Ericaceae) in eastern Canada". Botany 93, n.º 10 (outubro de 2015): 623–36. http://dx.doi.org/10.1139/cjb-2014-0223.
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Vaccinium oxycoccos s.l. is a complex of diploid and polyploid plants. The taxonomic relationship between the cytotypes is uncertain, with conflicting treatments in recent revisions. To clarify this situation, we investigated the relationships among ploidy, morphology, and genetic diversity in this group. We collected samples from a 1000 km transect in eastern Canada. We used flow cytometry to determine DNA ploidy, completed a morphometric analysis of flowering stems, and assessed genetic diversity using AFLPs. Diploids only occurred growing in mixed populations with tetraploids. There were statistically significant morphological differences between ploidies; however, tetraploid variation encompasses the diploid range for most characters. AFLP data demonstrate that the tetraploids have undergone genetic divergence since their formation, obscuring whether they are auto- or allo-polyploids. Our results agree with previous work using isozymes, which revealed genetic divergence of diploids and tetraploids in North America; and morphometry, which demonstrated clear distinctions between diploids and tetraploids in Europe. We found that diploids and tetraploids co-occur much more frequently than previously recognized, which may explain the conflicting treatment of this group by North American taxonomists. We recommend recognizing diploids and tetraploids as distinct species. The distribution of the two species in North America suggests two hypotheses regarding the successful establishment of the tetraploid: the tetraploids’ success is due to their capacity to exploit novel habitats outside the range of the diploid; or the tetraploid has in fact already out-competed the diploid in large areas of its former range, limiting the diploid to the far north. While we cannot rule out ongoing gene flow between diploids and tetraploids, it is likely a rare phenomenon in this group.
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Velguth, Peter H., e Harold Pellett. "Use of Flow Cytometric Measurement of Nuclear DNA Content to Assess Ploidy Level in Azalea". HortScience 31, n.º 4 (agosto de 1996): 627b—627. http://dx.doi.org/10.21273/hortsci.31.4.627b.
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We evaluated flow cytometric measurement of nuclear DNA content to determine ploidy level in azalea. If ploidy level correlates with DNA content, ploidy level could be determined more readily than by direct chromosome counts and assist in planning crosses and evaluating progeny. Tested plants included azalea cultivars, materials from the azalea breeding project at the Univ. of Minnesota, and species from the Rhododendron Species Botanic Garden and the North Carolina Arboretum. Data compiled from DNA assays of practically all material analyzed fell into distinct groups consistent with their being either diploid, triploid, or tetraploid. Additionally, a known diploid plant of each of four diploid species, together with a natural or derived tetraploid plant of each of these species was obtained. Results showed that the four diploids had a similar DNA content compared to one another. DNA content of the tetraploids was also similar, and the tetraploid's DNA content was approximately twice that of the diploids, as expected. Unfortunately, success with direct chromosome counts in other material has proven elusive, currently precluding direct correlation of DNA amount with ploidy level across other species and cultivars. Although many cases exist in the literature where DNA content has a direct relationship to ploidy level, this does not always hold. Although the majority of plants tested fell into a diploid, triploid, or tetraploid grouping based on DNA content, further study is required to determine the exact relationship between ploidy level and DNA content in azalea.
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James, Roberta M., Matthew H. Kaufman, Sheila Webb e John D. West. "Electrofusion of mouse embryos results in uniform tetraploidy and not tetraploid/diploid mosaicism". Genetical Research 60, n.º 3 (dezembro de 1992): 185–94. http://dx.doi.org/10.1017/s0016672300030937.
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SummarySome previous attempts to produce tetraploids experimentally have resulted in a proportion of treated embryos becoming 2n/4n mosaics at a frequency which may be as high as 20%, when using cytochalasin B as a fusigenic stimulus and cytogenetic techniques to identify putative tetraploid embryos. To investigate the possible occurrence of 4n/2n mosaicism, tetraploid embryos were produced by electrofusion, a process which allows adjacent blastomeres at the 2-cell stage to fuse following exposure to electric field pulses. Embryos used for electrofusion were hemizygous for a transgene consisting of approximately 1000 copies of the mouse β-globin gene. After in situ hybridization, one hybridization signal is expected per diploid genome. Tetraploid cells in 7·5-, 8·5-, 9·5- and 10·5-day-old conceptuses were distinguished from diploid cells by performing in situ hybridization on histological sections. The frequency of nuclei with two hybridization signals in the ‘hemizygous’ tetraploid embryos was compared to diploid embryos which were either hemizygous or homozygous for the β-globin transgene. Comparison of the frequency of nuclei with two hybridization signals between tissues of ‘hemizygous’ tetraploid conceptuses and homozygous diploid conceptuses showed no significant difference, which implies that the tissues in the tetraploid conceptuses were uniformly tetraploid. No evidence was found to suggest that electrofusion results in 2n/4n mosaicism.
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Liatukas, Žilvinas, e Jovita Bukauskaitė. "Differences in Yield of Diploid and Tetraploid Red Clover in Lithuania". Proceedings of the Latvian Academy of Sciences. Section B. Natural, Exact, and Applied Sciences 66, n.º 4-5 (1 de dezembro de 2012): 163–67. http://dx.doi.org/10.2478/v10046-012-0023-y.
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The research was carried out in 2003-2011 at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry. The fresh forage, dry matter (DM) and seed yields of red clover diploid and tetraploid populations and cultivars were determined. In total 58 diploids and 35 tetraploids were evaluated during four cycles in the study period. The average DM yield of diploids was 16.6 t ha -1 and of tetraploids was 17.8 t ha -1 . The tetraploid average DM yield surpassed that of diploids by only 6.5%. The seed yield was very low over the period. The average seed yield of diploids was 110.4 kg ha -1 . The average seed yield of tetraploids was 94.9 kg ha -1 . The diploid average seed yield was higher than that of tetraploids by 16.3%. The highest negative impact on seed yield was due to wet weather in the seed harvest year, which was favourable for development of diseases on above-ground plant parts. The study showed that tetraploid red clover had no significant advantage over diploid red clover in DM yield under Lithuanian conditions. Variation in seed yield showed that production of diploid red clover seed is less problematic. It seems that only directed disease resistance breeding can improve seed yield as well as forage yield of red clover.
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Adelberg, J., e J. Chen. "Environmental and Genetic Factors Affects Frequency of Tetraploid Regenerants from Immature Cotyledons of Melon". HortScience 33, n.º 3 (junho de 1998): 534a—534. http://dx.doi.org/10.21273/hortsci.33.3.534a.
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Immature cotyledons of three inbred melon genotypes, Cucumis melo L., and all hybrid cross-combinations were placed for a 1-week treatment on liquid/membrane system prior to 5-week regeneration culture on a MS medium containing 10 μM benzyladenine. Moving plants from agar to liquid/membrane culture system altered the frequency of tetraploid regenerants. The frequency of tetraploidy was also effected by sucrose level during the 1-week liquid treatment. The most stressful conditions, those where the least regenerants were found, had the highest number frequency of tetraploidy. Genotypic variation in the modes of genetic control was observed in the different environments. Tetraploid variation can be manipulated by one week treatment of immature cotyledons prior to regeneration.
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Talent, Nadia, e Timothy A. Dickinson. "The potential for ploidy level increases and decreases in Crataegus (Rosaceae, Spiraeoideae, tribe Pyreae)". Canadian Journal of Botany 85, n.º 6 (junho de 2007): 570–84. http://dx.doi.org/10.1139/b07-028.
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Unlike their diploid relatives, some triploid and tetraploid Crataegus frequently produce unreduced megagametophytes. In all cases, pollination is required for successful seed set, but in polyploids, endosperm formation can involve fertilization by either one or both sperm. Apomixis, in which the egg develops parthenogenetically, is widely documented in polyploid Crataegus, and as in many other groups with gametophytic apomeiosis, fertilization of unreduced eggs can also occur. Reciprocal pollinations were made between diploids, triploids, and tetraploids belonging to five taxonomic series in the genus to evaluate opportunities for gene flow between ploidy levels. The ploidy levels of embryo and endosperm in mature seeds, estimated from flow-cytometric DNA measurements, indicate the meiotic or apomeiotic origin of the megagametophyte and whether fertilization has occurred. These experiments demonstrated that although some tetraploids maintain near-obligate apomixis when supplied with pollen from diploids, others produced seeds containing embryos ranging from diploid to hexaploid. Allotriploid embryos were produced when a diploid was provided with pollen from tetraploids. A triploid produced tetraploid embryos when pollinated by a diploid and pentaploid embryos when pollinated by a tetraploid. Gametophytic apomixis in Crataegus thus can be facultative or near-obligate and may be implicated in the formation of interserial hybrids.
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Neill, Kristin E., e Ryan N. Contreras. "Does Inducing Tetraploidy in Vaccinium ovatum Improve Fruit Traits and Plant Architecture?" HortScience 57, n.º 2 (fevereiro de 2022): 312–18. http://dx.doi.org/10.21273/hortsci16332-21.
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Vaccinium ovatum (evergreen huckleberry) is an evergreen shrub native to the Pacific Northwest. Evergreen huckleberry is diploid (2n = 2x = 24), but unreduced gametes have been reported that facilitated in interspecific tetraploids. To our knowledge, tetraploid forms of evergreen huckleberry have not previously been evaluated. There is interest in this species as a native, edible, evergreen landscape shrub, but it requires improvement of the fruit and plant qualities for an eventual cultivar release. To obtain variation in plant qualities, we induced polyploidy in a collection of plants in 2013. The purpose of this study was to assess the impacts of polyploidy on the fruit and plant qualities of V. ovatum. This fruit and plant quality study provides a contribution to the scientific knowledge base that is currently lacking for evergreen huckleberries. Plant qualities were determined by measuring plant height and width, obtained in Fall 2017. The fruit volume (mm3) and for soluble solids content (SSC, °Brix) were measured using a digital caliper and a digital refractometer, respectively. Measurements were taken on diploid, mixoploid, and tetraploid (2x, 2x + 4x, 4x) cytotypes, once in 2017, five times over 9 weeks in 2018, and three times over 9 weeks in 2019. Tetraploids had larger fruit than diploids in 2017 (P < 0.0001), suggesting there was a gigas effect from polyploidy in evergreen huckleberries. However, during 2018 and 2019, tetraploid fruit was smaller than that of diploid and mixoploid genotypes. Differences were observed in diploid fruit volume among all years (P < 0.0001) such that 2019 was largest and 2017 was smallest. It is unclear what led to this variation. In tetraploids, SSC was statistically significant among years (P = 0.0002) such that 2017 was highest and 2019 was lowest. Although our preliminary data suggested that induced polyploidy may result in larger fruit, this was not observed in subsequent years, and it does not appear that tetraploids necessarily will have larger or sweeter fruit. However, these tetraploids may facilitate crossing with other species at the tetraploid level as a means for improvement of various traits.
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Eng, Wee Hiang, Wei Seng Ho e Kwong Hung Ling. "In vitro induction and identification of polyploid Neolamarckia cadamba plants by colchicine treatment". PeerJ 9 (27 de outubro de 2021): e12399. http://dx.doi.org/10.7717/peerj.12399.
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Polyploidization has played a crucial role in plant breeding and crop improvement. However, studies on the polyploidization of tropical tree species are still very scarce in this region. This paper described the in vitro induction and identification of polyploid plants of Neolamarckia cadamba by colchicine treatment. N. cadamba belongs to the Rubiaceae family is a natural tetraploid plant with 44 chromosomes (2n = 4x = 44). Nodal segments were treated with colchicine (0.1%, 0.3% and 0.5%) for 24 h and 48 h before transferring to shoot regeneration medium. Flow cytometry (FCM) and chromosome count were employed to determine the ploidy level and chromosome number of the regenerants, respectively. Of 180 colchicine-treated nodal segments, 39, 14 and 22 were tetraploids, mixoploids and octoploids, respectively. The highest percentage of polyploidization (20% octoploids; 6.7% mixoploids) was observed after treated with 0.3% colchicine for 48 h. The DNA content of tetraploid (4C) and octoploid (8C) was 2.59 ± 0.09 pg and 5.35 ± 0.24 pg, respectively. Mixoploid plants are made up of mixed tetraploid and octoploid cells. Chromosome count confirmed that tetraploid cell has 44 chromosomes and colchicine-induced octoploid cell has 88 chromosomes. Both octoploids and mixoploids grew slower than tetraploids under in vitro conditions. Morphological characterizations showed that mixoploid and octoploid leaves had thicker leaf blades, thicker midrib, bigger stomata size, lower stomata density, higher SPAD value and smaller pith layer than tetraploids. This indicates that polyploidization has changed and resulted in traits that are predicted to increase photosynthetic capacity of N. cadamba. These novel polyploid plants could be valuable resources for advanced N. cadamba breeding programs to produce improved clones for planted forest development.
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Talebi, Seyyedeh Farahnaz, Mohammad Jamal Saharkhiz, Maryam Jafarkhani Kermani e Yavar Sharafi. "Polyploidy increases tolerance to salt stress in Anise hyssop (Agastache foeniculum [Pursh.] Kuntze)". Caryologia 74, n.º 1 (20 de julho de 2021): 33–41. http://dx.doi.org/10.36253/caryologia-783.
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Salinization is one of the most serious environmental problems in agriculture. Polyploid induction could increase abiotic stress tolerance in plants. In this study, the effect of different NaCl concentrations (0, 50, 100 and 150 mM) was studied on diploid (2x) and tetraploid (4x) plants of anise hyssop (Agastache foeniculum) in vitro. The results indicated that salt stress reduced survival percentage, stem length, and leaf and shoot number in both tetraploid and diploid plants. However, tetraploid plants had better survival and growth rates compared with diploids. The highest antioxidant enzyme activity was observed in the plants treated with 100 mM NaCl, while increasing the salinity to 150 mM NaCl lowered the activity of antioxidant enzymes significantly. Essential oil content in diploid and tetraploid plants decreased as the concentration of NaCl was elevated. Also, salinity stress affected the chemical composition of essential oil in both diploid and tetraploid plants. In conclusion, the results indicated that tetraploids showed greater tolerance to salt stress compared with diploids, and polyploidy might be a useful breeding method in anise hyssop to amplify its tolerance to salt stress under soil salinity.