tetraploid species
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2021 ◽  
Author(s):  
Esther Ferrer ◽  
Araceli Fominaya ◽  
Yolanda Loarce ◽  
Juan M González

Cytogenetic observations, phylogenetic studies and genome analysis using high-density genetic markers have suggested a tetraploid Avena species carrying the C and D genomes (formerly C and A) to be the donor of all hexaploid oats (AACCDD). However, controversy surrounds which of the three extant CCDD tetraploid species - A. insularis , A. maroccana and A. murphyi - is most closely related to hexaploid oats. The present work describes a comparative karyotype analysis of these three CCDD tetraploid species and two hexaploid species, A. sativa and A. byzantina . This involved the use of FISH with six simple sequence repeats (SSRs) with the motifs CT, AAC, AAG, ACG, ATC and ACT, two repeated ribosomal sequences, and C genome-specific repetitive DNA.  The hybridization pattern of A. insularis with oligonucleotide (AC) 10 was also determined and compared with those previously published for A. sativa and A. byzantina . Significant differences in the 5S sites and SSR hybridization patterns of A. murphyi compared to the other CCDD species rule out its being directly involved in the origin of the hexaploids.  In contrast, the repetitive and SSR hybridization patterns shown by the D genome chromosomes, and by most of the C genome chromosomes of A. maroccana and A. insularis , can be equated with the corresponding chromosomes of the hexaploids.  Several chromosome hybridization signals seen for A. insularis , but not for A. maroccana , were shared with the hexaploid oats species, especially with A. byzantina .  These diagnostic signals add weight to the idea that the extant A. insularis , or a direct ancestor of it, is the most closely related progenitor of hexaploid oats. The similarity of the chromosome hybridization patterns of the hexaploids and CCDD tetraploids was taken as being indicative of homology.  A common chromosome nomenclature for CCDD species based on that of the hexaploid species is proposed.


Phytotaxa ◽  
2021 ◽  
Vol 489 (1) ◽  
pp. 1-9
Author(s):  
MICHAEL HOHLA ◽  
KONRAD PAGITZ ◽  
GERGELY KIRÁLY

Rubus ser. Rhamnifolii includes apomictic polyploid species, which occur in north-western and central Europe, with rare outposts to eastern central Europe. A regionally distributed tetraploid species of the series occurring north and south of the Eastern Alps in Austria and Germany, Rubus noricus is described here. The new species is morphologically compared with similar taxa of the series, moreover, comprehensive iconography, data on distribution and ecology are presented.


2021 ◽  
Author(s):  
Rena Sanetomo ◽  
Akito Nashiki

Abstract Tetrad sterility, in which only clumps of four premature pollen grains are released from anthers, has been observed in some modern potato cultivars. It is a form of cytoplasmic male sterility caused by the cytoplasm derived from the Mexican tetraploid species Solanum stoloniferum Schlechtd. et Bché., an important source of resistance to Potato virus Y in potato breeding. However, since S. stoloniferum is highly polymorphic, the source of tetrad-sterility-causing cytoplasm is unknown among diverse S. stoloniferum accessions. In this study, we directly crossed 24 S. stoloniferum accessions with pollen from 4x S. tuberosum and obtained 39 hybrids from 12 accessions. Nineteen hybrids from six accessions showed tetrad sterility, with either D/γ- or W/γ-type cytoplasm, and were triploid, tetraploid, or hexaploid. The W/γ-type cytoplasm was not necessarily associated with tetrad sterility. Sequence comparisons of 17 mitochondrial genes and their intergenic regions revealed a length polymorphism in the intergenic region between rpl5 and rps10, in which an amplified band of 859 bp was associated with tetrad sterility. This specific cytoplasm causing tetrad sterility is named TSCsto. The 859-bp band would be a useful diagnostic marker for identifying TSCsto in potato breeding.


2021 ◽  
Author(s):  
Fatemeh Nezhadi ◽  
farzad fayaz ◽  
Hooshmand Safari ◽  
Ezzat Karami ◽  
Abdol Rahman Rahimi

Abstract We conducted the present study on seven important medicinal species of Achillea (4 replications per species) (in a total of 28 samples) in their natural habitats in two consecutive years (2018, 2019) in terms of morphological, cytogenetic, and ecological aspects. This study aimed to examine the environmental variables affecting the morphology, cytogenetics, and evolution of the plant. The results indicated that the populations had a Ploidy base number (x= 9) and the diploid, tetraploid, and hexaploid levels were observed. In addition to the inter-species diversity, there was the intra-species genetic diversity as (4x, 6x) Ac. millefolium (2x, 4x), Ac.vermicularis (2x, 4x), Ac. tenuifolia (2x, 4x), Ac. Alppica(2x) , Ac.talagonica(2x),Ac. biebersteinii, and Ac.wilhelmsii (4x). Further studies also indicated that 11 out of 28 populations had 1A symmetry, 15 populations had 2B symmetry, a population had 2A, and another population had 2B. Principal component analysis (PCA) of cytogenetic variables could not differentiate the species well probably due to the superiority of intra-species diversity of populations to inter-species diversity. Therefore, it seems that the evolution and speciation of this genus are mostly due to the increase or decrease in the amount of chromatin and chromosome length. The examination of principal component analysis in environmental indices also showed that Ac. millefolium hexaploid species was more adapted to the environment with higher percentages of clay and silt while the Ac.tenuifolia tetraploid species preferred a sandy habitat over other environmental factors. Furthermore, Ac.vermicularis tetraploid species indicated the greatest sensitivity to altitude. However, the Ac.biebersteinii tetraploid species reacted to meteorological parameters, such as perception rate and minimum temperature.


HortScience ◽  
2021 ◽  
pp. 1-6
Author(s):  
Mark K. Ehlenfeldt ◽  
James L. Luteyn

Vaccinium meridionale (section Pyxothamnus), a tetraploid species native to higher altitude locations in Jamaica, Colombia, and Venezuela, is of considerable interest to blueberry breeders for its profuse, concentrated flowering and monopodial plant structure, both of which may be useful in breeding for mechanical harvest. In this study, tetraploid V. meridionale was successfully hybridized as a male with 4x V. corymbosum (section Cyanococcus, highbush blueberry). The first-generation hybrids with highbush blueberry selections were intermediate in morphology and notably vigorous. The 4x F1 hybrids displayed variable branching structure, dormancy, prolificacy, fruit wax, etc.; however, most appear to be deciduous to semi-evergreen, with small, dark-colored fruit. The F1 hybrids displayed good fertility as females in backcrosses to 4x highbush and these crosses have produced numerous offspring morphologically indistinguishable from 4x highbush at the seedling stage. Evaluations of male fertility found variation for pollen production and quality but, significantly, found some clones with very good shed, high stainability, and almost complete tetrad production. The fertility suggests that these hybrids, despite being derived from intersectional crosses, might be conventionally used without significant difficulty. These hybrids also have potential value for the nascent V. meridionale breeding efforts occurring in Colombia, South America.


2021 ◽  
Vol 36 ◽  
pp. 01028
Author(s):  
G.V. Tobolova

The studies of plants’ assimilation activity of the Triticum carthlicum Nevski. (=Triticum persicum Vav.) tetraploid species’ variety samples have been carried out in the subtaiga zone (Aromashevo) and the northern forest-steppe zone (Tyumen). The number of leaves on plants by zones varied from three to five. Measurements showed that the lamina length varied from 6.4-23.7% in the northern forest-steppe zone and from 0 to 21.9% in Aromashevo. The lamina area on the main shoot of the Triticum carthlicum Nevski variety samples in the northern forest-steppe zone amounted to 62.3 cm2, which was 26 cm2 less than in the subtaiga zone. Calculation of net photosynthetic productivity in northern forest-steppe zone showed that Triticum carthlicum Nevski variety samples formed from 10.864g*m2/day to 20.764 g*m2/day, giving way to durum and soft wheat. In the subtaiga zone, PPn of Triticum carthlicum Nevski wheat varied from 9.088 to 13.827 g*m2/day, significantly yielding Bezenchukskaya 139 variety.


2020 ◽  
Vol 77 (6) ◽  
pp. 413-427
Author(s):  
S.L. Mosyakin ◽  
◽  
B. Mandák ◽  
◽  

Nomenclatural corrections and comments are provided on several taxa of Chenopodiaceae occurring in the Himalayas and Xizang/Tibet and adjacent areas, following the recent monographic revision of the family in that region and earlier publications. In particular, the original identity of the name Atriplex bengalensis (Chenopodium bengalense) is discussed and it is confirmed, based on additional evidence, that the name was originally (before its epitypification in 2014) applicable to a robust diploid of the Chenopodium ficifolium aggregate, not to the robust hexaploid currently known as C. giganteum. It is thus also concluded that the recent proposal by Mosyakin and Mandák (2018) to conserve the name C. giganteum with a conserved type corresponding to the current understanding and application of that name will best serve nomenclatural stability. A nomenclatural solution alternative to the proposal to reject the name A. bengalensis might be the following: (1) to conserve the name Atriplex bengalensis with a conserved C. ficifolium against C. bengalense. The nomenclaturally paradoxical situation with the names Chenopodium pallidum, C. harae, and Atriplex pallida (all now considered homotypic, as justified by Mosyakin and McNeill in 2018), which emerged from the conflicting lectotypification and epitypification of the name C. pallidum, is revisited and reconsidered. Possible options for dealing with that nomenclatural problem are outlined: (1) keeping the status quo, (2) proposing to conserve the name C. pallidum with a conserved type other than the standing lectotype, and (3) proposing to reject the name C. pallidum. The last option is considered preferable. Additional considerations are presented on a possible taxonomic identity of Chenopodium strictum as originally described by Roth; it is confirmed that that name was misapplied to a widespread Eurasian tetraploid species now properly known as C. betaceum. The identity of the name Bassia fiedleri is discussed; being a replacement name for Echinopsilon divaricatum, it is homotypic with Bassia divaricata (Kar. & Kir.) Kuntze (nom. illeg., non F. Muell.) and is a taxonomic synonym of Grubovia dasiphylla (as correctly stated by Kadereit and Freitag in 2011), but not a synonym of Bassia scoparia. Several comments on type designations of selected taxa of Chenopodiaceae from the Sino-Himalayan region are provided as well; e.g., for Acroglochin persicarioides and associated names, Chenopodium karoi, and Salsola monoptera.


Genome ◽  
2020 ◽  
Vol 63 (11) ◽  
pp. 547-560 ◽  
Author(s):  
James P. Bogart ◽  
Patrick Burgess ◽  
Jinzhong Fu

Hyla chrysoscelis and H. versicolor are common treefrogs in eastern North America and are a cryptic diploid–tetraploid species pair. They are morphologically identical but H. versicolor is a tetraploid. They can be identified acoustically by the male’s advertisement mating call, which has a pulse repetition rate that has twice as many pulses per second in the diploid species, H. chrysoscelis. We used isozymes, microsatellite DNA alleles, and mitochondrial cytochrome b sequences to test the hypothesis that gene exchange occurs between the diploid and tetraploid species in sympatric populations. Each method provided results that are best explained by occasional hybridization of female H. versicolor and male H. chrysoscelis. We propose that H. versicolor first arose from an autotriploid H. chrysoscelis female that produced unreduced triploid eggs. After H. versicolor became established, genes could be passed from H. chrysoscelis to H. versicolor in sympatric populations when these species hybridize. Their F1 female progeny produce unreduced triploid eggs that are fertilized by haploid H. chrysoscelis sperm to reconstitute H. versicolor. Genes can be passed from diploid H. chrysoscelis to tetraploid H. versicolor in sympatric populations.


2020 ◽  
Vol 36 (5) ◽  
pp. 668-674
Author(s):  
Masako Ishihara ◽  
Keigo Morita ◽  
Yuka Iguchi ◽  
Kosuke Takaku ◽  
Keisuke Takata ◽  
...  

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