scholarly journals Ploidy Level and DNA Content of Perennial Ryegrass Germplasm as Determined by Flow Cytometry

HortScience ◽  
2009 ◽  
Vol 44 (7) ◽  
pp. 2049-2052 ◽  
Author(s):  
Ying Wang ◽  
Cale A. Bigelow ◽  
Yiwei Jiang

Perennial ryegrass (Lolium perenne L.) is a widely used cool-season turfgrass species. The exact ploidy levels of the worldwide perennial ryegrass accessions in the USDA National Plant Germplasm System (NPGS) are unknown, which could complicate future use and breeding efforts. The objective of this study was to determine the ploidy level and DNA content of the 194 USDA NPGS perennial ryegrass accessions and six commercial cultivars (Brightstar SLT, Catalina II, Divine, Inspire, Manhattan 4, Silver Dollar) using flow cytometry. Among the 200 accessions, 194 diploids and six tetraploids were identified. Three tetraploids originated from Canada with the remaining from Ireland, Japan, and The Netherlands. The average DNA content was 5.60 pg/2C for the diploid and 11.45 pg/2C for the tetraploid. The 2C DNA content was positively correlated (r = 0.23, P < 0.01) with seedling plant height but not seedling leaf width. This ploidy data provide important information for future marker trait analysis and cultivar improvement.

1998 ◽  
Vol 76 (1) ◽  
pp. 157-165 ◽  
Author(s):  
Jérôme Thibault

Flow cytometry (FCM) has been used to estimate the nuclear DNA content of 11 Salix species and 5 hybrids. One hundred and sixty nine individuals were studied including 159 individuals from a sequence of 32 communities along a stretch of river in France and 10 individuals from French and English collections for comparison. Isolated nuclei were stained with propidium iodide. FCM was a significantly more practical and rapid technique than that of establishing the karyotype to survey many samples of Salix for variation in ploidy. The 2C DNA amounts for diploid species ranged from 0.76 to 0.98 pg, and tetraploid values ranged from 1.62 to 1.80 pg. The DNA values were consistent with the known ploidy levels. With the exception of a doubtful Salix xquercifolia, ploidy levels and DNA amounts of hybrids were intermediate compared with those of their parents. Intraspecific variation of nuclear DNA values including instrumental variation was low (i.e., 6-11% at the same ploidy level). FCM appeared to be an accurate tool for determination of Salix triploid hybrids. However, it remains limited concerning hybrids from crosses between species of the same ploidy level. Results suggest that natural hybridization might not be frequent in the communities studied, although they have been subject to disturbance. Previous overestimates of hybridization frequency in willows were probably due to misinterpretation of the effects of the environment on Salix spp. morphology; however, the extent and mechanisms of introgression in the genus remain to be further investigated. Key words: flow cytometry, Salix, hybridization, nuclear DNA content, riparian vegetation, disturbance.


Genes ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1950
Author(s):  
Guadalupe Palomino ◽  
Javier Martínez-Ramón ◽  
Verónica Cepeda-Cornejo ◽  
Miriam Ladd-Otero ◽  
Patricia Romero ◽  
...  

Echeveria is a polyploid genus with a wide diversity of species and morphologies. The number of species registered for Echeveria is approximately 170; many of them are native to Mexico. This genus is of special interest in cytogenetic research because it has a variety of chromosome numbers and ploidy levels. Additionally, there are no studies concerning nuclear DNA content and the extent of endopolyploidy. This work aims to investigate the cytogenetic characteristics of 23 species of Echeveria collected in 9 states of Mexico, analyzing 2n chromosome numbers, ploidy level, nuclear DNA content, and endopolyploidy levels. Chromosome numbers were obtained from root tips. DNA content was obtained from the leaf parenchyma, which was processed according to the two-step protocol with Otto solutions and propidium iodide as fluorochrome, and then analyzed by flow cytometry. From the 23 species of Echeveria analyzed, 16 species lacked previous reports of 2n chromosome numbers. The 2n chromosome numbers found and analyzed in this research for Echeveria species ranged from 24 to 270. The range of 2C nuclear DNA amounts ranged from 1.26 pg in E. catorce to 7.70 pg in E. roseiflora, while the 1C values were 616 Mbp and 753 Mbp, respectively, for the same species. However, differences in the level of endopolyploidy nuclei were found, corresponding to 4 endocycles (8C, 16C, 32C and 64C) in E. olivacea, E. catorce, E. juarezensis and E. perezcalixii. In contrast, E. longiflora presented 3 endocycles (8C, 16C and 32C) and E. roseiflora presented 2 endocycles (8C and 16C). It has been suggested that polyploidization and diploidization processes, together with the presence of endopolyploidy, allowed Echeveria species to adapt and colonize new adverse environments.


2002 ◽  
Vol 127 (5) ◽  
pp. 767-775 ◽  
Author(s):  
Rengong Meng ◽  
Chad Finn

Nuclear DNA flow cytometry was used to differentiate ploidy level and determine nuclear DNA content in Rubus. Nuclei suspensions were prepared from leaf discs of young leaves following published protocols with modifications. DNA was stained with propidium iodide. Measurement of fluorescence of 40 genotypes, whose published ploidy ranged from diploid to dodecaploid, indicated that fluorescence increased with an increase in chromosome number. Ploidy level accounted for 99% of the variation in fluorescence intensity (r2 = 0.99) and variation among ploidy levels was much higher than within ploidy levels. This protocol was used successfully for genotypes representing eight different Rubus subgenera. Rubus ursinus Cham. and Schldl., a native blackberry species in the Pacific Northwest, which has been reported to have 6x, 8x, 9x, 10x, 11x, and 12x forms, was extensively tested. Genotypes of R. ursinus were predominantly 12x, but 6x, 7x, 8x, 9x, 11x, and 13x forms were found as well. Attempts to confirm the 13x estimates with manual counts were unsuccessful. Ploidy level of 103 genotypes in the USDA-ARS breeding program was determined by flow cytometry. Flow cytometry confirmed that genotypes from crosses among 7x and 4x parents had chromosome numbers that must be the result of nonreduced gametes. This technique was effective in differentiating chromosome numbers differing by 1x, but was not able to differentiate aneuploids. Nuclear DNA contents of 21 diploid Rubus species from five subgenera were determined by flow cytometry. Idaeobatus, Chamaebatus, and Anaplobatus were significantly lower in DNA content than those of Rubus and Cylactis. In the Rubus subgenus, R. hispidus and R. canadensis had the lowest DNA content and R. sanctus had the highest DNA content, 0.59 and 0.75 pg, respectively. Idaeobatus had greater variation in DNA content among diploid species than the Rubus subgenus, with the highest being from R. ellipticus (0.69 pg) and lowest from R. illecebrosus (0.47 pg).


Author(s):  
Yinjie Qiu ◽  
Sierra Hamernick ◽  
Joan Barreto Ortiz ◽  
Eric Watkins

ABSTRACTFestuca ovina is a fine fescue that is used as a low-input turfgrass. The ploidy levels of F. ovina accessions held by the USDA National Plant Germplasm System (NPGS) are unknown, limiting the use of the germplasm in breeding programs. The objective of this study was to determine DNA content and estimate ploidy of these 127 accessions. Among the accessions, we identified a wide range of ploidy levels from diploid to octoploid. We also found the accessions with higher ploidy levels usually had larger seed size. These results will be informative to plant breeders and researchers using germplasm from the F. ovina collection and point to challenges in maintaining polyploid, outcrossing germplasm seed stocks in common nurseries.


1994 ◽  
Vol 24 (5) ◽  
pp. 1074-1078 ◽  
Author(s):  
D. Grattapaglia ◽  
H.D. Bradshaw Jr.

This paper reports the nuclear DNA content estimates obtained by flow cytometry for a group of twelve Eucalyptus species and five fast-growing hybrids that includes those most widely planted throughout the world. Estimates of nuclear (2C) DNA content for the species surveyed ranged from 0.77 pg/2C for Eucalyptuscitriodora Hook. (subgenus Corymbia) to 1.47 pg/2C for Eucalyptussaligna Smith (subgenus Symphyomyrtus). This range corresponds to a haploid genome size range of 370–700 megabase pairs. The average physical equivalent of a 1 cM distance could be as low as 200 kilobase pairs in Eucalyptus, an attractive feature for positional cloning efforts in woody plants. The closer the species were in phylogenetic relationship the more similar were their nuclear DNA content values. All the interspecific hybrids surveyed displayed a nuclear DNA content in the expected intermediate range between the respective parental species, with the exception of one originating from Rio Claro, Brazil, whose exact parentage is unknown. No evidence of polyploidy was observed in any of the hybrids. The flow cytometry procedure employed in this study is an efficient method for investigating ploidy levels of high yielding hybrids of Eucalyptus.


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 439D-439 ◽  
Author(s):  
Mary Ann Start ◽  
James Luby ◽  
Robert Guthrie ◽  
Debby Filler

The hardy Actinidia species represent a source of genetic diversity for improving A. deliciosa (kiwifruit) as well as for creating new economically important cultivars through intra- and interspecific crosses. Attempts at breeding in Actinidia have been complicated by the existence of intraspecific as well as interspecific variation in ploidy. The haploid chromosome number in Actinidia is 29 and diploid (2n=2x=58), tetraploid (2n=4x=116), and hexaploid (2n=6x=174) levels have been identified. Because of the problems encountered when crossing parents differing in ploidy level, it is desirable to know the ploidy levels of plants to be used in breeding. We determined the ploidy levels of 61 Actinidia accessions currently available in the U.S., including primarily accessions of relatively winter-hardy species. The 61 accessions, representing eight species and three interspecific hybrids, were screened for ploidy using flow cytometry. Mitotic root tip cells from one plant from each putative ploidy level were examined microscopically to confirm the ploidy level derived from flow cytometry. There were 17 diploids, 40 tetraploids, and 4 hexaploids. Intraspecific variation was not found among accessions of the species arguta, callosa, deliciosa, kolomikta, melanandra, polygama, or purpurea. All kolomikta and polygama accessions were diploid. All arguta, callosa, melanandra, and purpurea accessions were tetraploid. Actinidia deliciosa was hexaploid. One chinensis accession was tetraploid. Two accessions (NGPR 0021.14 and 0021.3), acquired as chinensis, were hexaploid and may, in fact, be A. deliciosa based on their morphology. `Issai' (arguta × polygama) was hexaploid and `Ken's Red' and `Red Princess' (both melanandra × arguta) were tetraploid.


HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 580e-580
Author(s):  
Rodomiro Ortiz ◽  
D.E. Costich ◽  
T.P. Meagher ◽  
N. Vorsa

DNA flow cytometry was used to determine nuclear DNA content in diploid blueberry species, and 3x, 4x, 5x, and 6x ploidy levels. Relative fluorescence intensity of stained nuclei measured by flow cytometry was a function of the number of chromosome sets (X): Y = 3.7X – 2.3 (r2 = 95.1%). DNA flow cytometry should be useful for ploidy level determination in the seedling stage. A significant linear relationship was established between nuclear DNA content and number of chromosomes (x); DNA (pg) = 0.52 x1 (r2 = 99.8%). Based on this equation the haploid genome DNA amount (1C) was calculated as 0.62 ± 0.08 pg, with an approximate haploid genome size of 602 Mbp/1C. The results indicate that conventional polyploid evolution occured in the section Cyanococcus, genus Vaccinium: the increase in DNA was concurrent with increase in chromosome number. DNA content differences among 2x species were correlated with Nei's genetic distance estimates based on 20 isozyme markers. Most of the variation was among species (49%), with 26% between populations within species, and 25% within populations.


2012 ◽  
Vol 36 (6) ◽  
pp. 599-607
Author(s):  
Ana Luiza de Oliveira Timbó ◽  
Roselaine Cristina Pereira ◽  
Vanderley Borges dos Santos ◽  
Fausto Souza Sobrinho ◽  
Lisete Chamma Davide

Flow cytometry allows to estimate the DNA content of a large number of plants quickly. However, inadequate protocols can compromise the reliability of these estimates leading to variations in the values of DNA content the same species. The objective of this study was to propose an efficient protocol to estimate the DNA content of Brachiaria spp. genotypes with different ploidy levels using flow cytometry. We evaluated four genotypes (B. ruziziensis diploid and artificially tetraploidized; a tetraploid B. brizantha and a natural triploid hybrid), three buffer solutions (MgSO4, Galbraith and Tris-HCl) and three species as internal reference standards (Raphanus sativus, Solanum lycopersicum e Pisum sativum). The variables measured were: histogram score (1-5), coefficient of variation and estimation of DNA content. The best combination for the analysis of Brachiaria spp. DNA content was the use of MgSO4 buffer with R. sativus as a internal reference standard. Genome sizes expressed in picograms of DNA are presented for all genotypes and the importance of the histogram score on the results reliability of DNA content analyses were discussed.


2021 ◽  
Author(s):  
Paulina Tomaszewska ◽  
Till K. Pellny ◽  
Luis Miguel Hernandez ◽  
Rowan A. C. Mitchell ◽  
Valheria Castiblanco ◽  
...  

We aimed to develop an optimized approach to determine ploidy for dried leaf material in a germplasm collection of a tropical forage grass group, including approaches to collect, dry and preserve plant samples for flow cytometry analysis. Urochloa (including Brachiaria, Megathyrus and some Panicum) tropical grasses are native to Africa and are now, after selection and breeding, planted worldwide, particularly in South America, as important forages with huge potential for further sustainable improvement and conservation of grasslands. The methods enable robust identification of ploidy levels (coefficient of variation, CV, typically <5%). Ploidy of some 353 forage grass accessions (ploidy range from 2 to 9), from international genetic resource collections, showing variation in basic chromosome numbers and reproduction modes (apomixis and sexual), were determined using our defined standard protocol. Two major Urochloa agamic complexes used in the current breeding programs at CIAT and EMBRAPA: the ' brizantha' and 'humidicola' agamic complexes are variable, with multiple ploidy levels and DNA content. U. brizantha has odd level of ploidy (x=5), and the relative differences in nuclear DNA content between adjacent cytotypes is reduced, thus more precise examination of this species is required. Ploidy measurement of U. humidicola revealed some aneuploidy.


2019 ◽  
Vol 6 (1) ◽  
pp. 1-7
Author(s):  
Diego Pandeló José ◽  
José Marcello Salabert De Campos ◽  
Lyderson Facio Viccini ◽  
Emilly Ruas Alkimim ◽  
Marcelo De Oliveira Santos

Lippia lacunosa is a Brazilian savanna plant that belongs to the Verbenaceae family. It has been used in folk medicine as a treatment for different diseases. This species represents an endangered Brazilian medicinal plant, and this is the first report documenting a reliable protocol for the in vitro propagation and regeneration of L. lacunosa. Axenic explants were cultivated in MS medium containing different concentrations of naphthalene acetic acid (NAA) to induce root growth. The mean shoot length and the number of roots were highest with 0.06 mg·L-1 NAA. The highest number of buds in shoot regeneration was induced with 2 mg·L-1 6-benzylaminopurine (BA). To obtain a long-term culture, the dwarf shoots were elongated on MS media containing 0.5 mg·L-1 BA alternated with MS containing 2 mg·L-1 BA every 40 days. In the present protocol, the long-term shoots retained the ability to root even after long periods of BA treatment. In addition, we evaluated the nuclear DNA content and ploidy levels, including the occurrence of endopolyploidy, in long-term micropropagated plant leaves using flow cytometry analysis. The plants propagated in vitro over several years possessed nuclear DNA contents ranging from 2.940 to 3.095 pg, and no differences in DNA content were found among in vitro plants or between these plants and the control (L. lacunosa from a greenhouse with a DNA content of 3.08 pg). The flow cytometry analysis also demonstrated that there was no polyploidization. The present study will be useful for biotechnological approaches and provides the first estimate of the nuclear DNA content of this species using flow cytometry.


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