The potential for ploidy level increases and decreases in Crataegus (Rosaceae, Spiraeoideae, tribe Pyreae)

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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Non-linear genetic diversity and notable population differentiation caused by low gene flow of bermudagrass [Cynodon dactylon (L.) Pers.] along longitude gradients

PeerJ ◽

10.7717/peerj.11953 ◽

2021 ◽

Vol 9 ◽

pp. e11953

Author(s):

Jing-Xue Zhang ◽

Miaoli Wang ◽

Jibiao Fan ◽

Zhi-Peng Guo ◽

Yongzhuo Guan ◽

...

Keyword(s):

Genetic Diversity ◽

Population Structure ◽

Gene Flow ◽

Genetic Distance ◽

Ploidy Level ◽

Population Genetic ◽

Annual Precipitation ◽

Mean Annual Precipitation ◽

Ploidy Levels ◽

Population Genetic Diversity

Background Environmental variation related to ecological habitat is the main driver of plant adaptive divergence. Longitude plays an important role in the formation of plant population structure, indicating that environmental differentiation can significantly shape population structure. Methods Genetic diversity and population genetic structure were estimated using 105 expressed sequence tag-derived simple sequence repeat (EST-SSR) loci. A total of 249 C. dactylon (L.) Pers. (common bermudagrass) individuals were sampled from 13 geographic sites along the longitude (105°57′34″–119°27′06″E). Results There was no obvious linear trend of intra-population genetic diversity along longitude and the intra-population genetic diversity was not related to climate in this study. Low gene flow (Nm = 0.7701) meant a rich genetic differentiation among populations of C. dactylon along longitude gradients. Significantly positive Mantel correlation (r = 0.438, P = 0.001) was found between genetic distance and geographical interval while no significant partial Mantel correlation after controlling the effect of mean annual precipitation, which indicated geographic distance correlated with mean annual precipitation affect genetic distance. The genetic diversity of C. dactylon with higher ploidy level was higher than that with lower ploidy level and groups of individuals with higher ploidy level were separated further away by genetic distance from the lower ploidy levels. Understanding the different genetic bases of local adaptation comparatively between latitude and longitude is one of the core findings in the adaptive evolution of plants.

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Doubled-haploid Broccoli Production Using Anther Culture: Effect of Anther Source and Seed Set Characteristics of Derived Lines

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.123.1.73 ◽

1998 ◽

Vol 123 (1) ◽

pp. 73-77 ◽

Cited By ~ 10

Author(s):

Mark W. Farnham

Keyword(s):

Flow Cytometry ◽

Plant Regeneration ◽

Brassica Oleracea ◽

Anther Culture ◽

Seed Production ◽

Ploidy Level ◽

Doubled Haploid ◽

Seed Set ◽

Dna Flow Cytometry ◽

Ploidy Levels

Using anther culture to generate doubled-haploid (DH) homozygous lines for use as parents in F1 hybrid crosses has become a common practice in breeding broccoli (Brassica oleracea L. Italica Group). During anther culture and subsequent embryogenesis and plant regeneration, polyploidization of microspore-derived embryos may not occur or it may occur accompanied by a doubling, tripling, quadrupling, octupling, or irregular polyploidization of the genome. Thus regenerants from the process can be haploids, diploids, triploids, tetraploids, octaploids, or aneuploids. The objectives of this research were to 1) conduct repeat cycles of broccoli anther culture using a group of F1 hybrids as anther donors and develop populations of regenerants; 2) analyze resulting populations using DNA flow cytometry and determine the influence of F1 source on frequency of different ploidy levels among regenerants; and 3) compare seed set in broccoli inbreds developed in a traditional selfing program compared to seed set in DH broccoli derived from anther culture. In two cycles (1994 and 1995) of anther culture, anther-derived populations of regenerants were developed using the F1 hybrids `Marathon', `Everest', `High Sierra', and `Futura' as sources of anthers. In 1994, `Everest', `High Sierra', and `Futura' yielded populations that included 2% to 7% haploids, 53% to 56% diploids, 32% to 38% tetraploids, and 5% to 6% other types. `Marathon'-derived regenerants were 5% haploid, 78% diploid, 15% tetraploid, and 2% other, showing significantly more diploids. In 1995, `Marathon' regenerants again included significantly more diploids and fewer tetraploids than those derived from other F1 sources, confirming that the genotype of the anther source affects the frequency of a particular ploidy level among regenerants derived from culture. In manual self-pollinations of 1994 regenerants, only diploids and rare tetraploids set seed. When plants that set no seed were discounted, seed production following manual self pollinations of 1995 regenerants was not significantly different from that of traditional inbreds derived from the same F1 sources.

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Chromosome Numbers in the Chilean Endemic Genus Leucocoryne (Huilli)

Journal of the American Society for Horticultural Science ◽

10.21273/jashs.129.1.0077 ◽

2004 ◽

Vol 129 (1) ◽

pp. 77-80 ◽

Cited By ~ 4

Author(s):

Loreto Araneda ◽

Paulina Salas ◽

Leví Mansur

Keyword(s):

Gene Flow ◽

Ploidy Level ◽

Chromosome Numbers ◽

Hybrid Population ◽

Natural Hybrid ◽

Normal Complement ◽

Ploidy Levels ◽

Endemic Genus ◽

Number Of Species ◽

Eleven Species

Few cytological studies have been conducted on the endemic Chilean genus Leucocoryne, which is comprised of 14 species and a number of populations whose taxonomy has not been elucidated. Eleven species/populations of Leucocoryne have been examined cytologically and L. ixioides (Hook.) Lindl., L. coquimbensis var coquimbensis F.Phil., L. narcissoides R. Phil., L. sp. `Alcones', L. sp. `Talinay' and L. sp. `Combarbalá' were observed to be 2n = 18; L. purpurea Gay, L. sp. `Ñague', L. sp. `Alicahue' and L. sp. `Pichicuy' are 2n = 10 and L. coquimbensis var alba had 2n = 14. Furthermore, a natural hybrid population of L. purpurea and L. coquimbensis var coquimbensis had individuals with 2n = 14 and 2n = 22 chromosomes in addition to the normal complement of 2n = 10 and 2n = 18. The results indicate that Leucocoryne with the exception of L. coquimbensis var alba is typically either 2n = 10 or 2n = 18 with a similar number of species or populations at each ploidy level. Furthermore, the hybrid population demonstrated that there is gene flow between the species at different ploidy levels.

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Ploidy Levels and Genome Sizes of Berberis L. and Mahonia Nutt. Species, Hybrids, and Cultivars

HortScience ◽

10.21273/hortsci.45.7.1029 ◽

2010 ◽

Vol 45 (7) ◽

pp. 1029-1033 ◽

Cited By ~ 19

Author(s):

Todd J. Rounsaville ◽

Thomas G. Ranney

Keyword(s):

Pisum Sativum ◽

Ploidy Level ◽

Flow Cytometric Analysis ◽

Internal Standard ◽

Berberis Thunbergii ◽

Ploidy Levels ◽

Flow Cytometric ◽

Representative Species ◽

Species Hybrids ◽

First Time

An extensive survey of genome sizes and ploidy levels was conducted for a diverse collection of Berberis and Mahonia taxa (Berberidaceae). Propidium iodide flow cytometric analysis was conducted using Pisum sativum L. ‘Ctirad’ (2C DNA = 8.76 pg) as an internal standard to determine genome sizes. Mean 1CX genome sizes varied between the two Mahonia subgenera (Occidentales = 1.17 ± 0.02, Orientales = 1.27 ± 0.01), whereas those of Berberis subgenera were similar (Australes = 1.45 ± 0.03, Septentrionales = 1.47 ± 0.02) and each significantly larger than those of Mahonia. Traditional cytology was performed on representative species to calibrate genome sizes with ploidy levels. Polyploidy among both wild and cultivated taxa was found to be rare. Although the majority of species were determined to be diploid with 2n = 2x = 28, artificially induced autopolyploid Berberis thunbergii seedlings were confirmed to be tetraploid and an accession of Mahonia nervosa was confirmed to be hexaploid. Genome size and ploidy level reports for the majority of taxa sampled are presented for the first time and are intended to be of use to plant breeders, ecologists, and systematists.

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Gene Flow among Populations of Two Rare Co-Occurring Fern Species Differing in Ploidy Level

PLoS ONE ◽

10.1371/journal.pone.0045855 ◽

2012 ◽

Vol 7 (9) ◽

pp. e45855 ◽

Cited By ~ 11

Author(s):

Anna Bucharová ◽

Zuzana Münzbergová

Keyword(s):

Gene Flow ◽

Ploidy Level ◽

Fern Species

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Ploidy Levels of Hardy Actinidia Accessions in the U.S. Determined by Flow Cytometry

HortScience ◽

10.21273/hortsci.32.3.439d ◽

1997 ◽

Vol 32 (3) ◽

pp. 439D-439 ◽

Cited By ~ 2

Author(s):

Mary Ann Start ◽

James Luby ◽

Robert Guthrie ◽

Debby Filler

Keyword(s):

Flow Cytometry ◽

Ploidy Level ◽

Interspecific Variation ◽

Root Tip ◽

Interspecific Crosses ◽

Ploidy Levels ◽

Haploid Chromosome Number ◽

Tip Cells ◽

Root Tip Cells ◽

The U.S

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.

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Ploidy levels in silverside fishes (Atherinidae, Menidia) on the Texas coast: flow-cytometric analysis of the occurrence of allotriploidy

Journal of Fish Biology ◽

10.1111/j.1095-8649.1988.tb05427.x ◽

1988 ◽

Vol 32 (6) ◽

pp. 835-844 ◽

Cited By ~ 17

Author(s):

A. A. Echelle ◽

A. F. Echelle ◽

L. E. DeBault ◽

D. W. Durham

Keyword(s):

Flow Cytometric Analysis ◽

Texas Coast ◽

Ploidy Levels ◽

Flow Cytometric

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Seed set and gene flow patterns in an experimental population of an endangered heterostylous herb with controlled local opposite-morph density

Functional Ecology ◽

10.1046/j.1365-2435.2003.00773.x ◽

2003 ◽

Vol 17 (5) ◽

pp. 680-689 ◽

Cited By ~ 25

Author(s):

F. Ishihama ◽

C. Nakano ◽

S. Ueno ◽

M. Ajima ◽

Y. Tsumura ◽

...

Keyword(s):

Gene Flow ◽

Seed Set ◽

Flow Patterns ◽

Experimental Population

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Genome size and nucleotypic variation in Malus germplasm

Genome ◽

10.1139/g08-109 ◽

2009 ◽

Vol 52 (2) ◽

pp. 148-155 ◽

Cited By ~ 13

Author(s):

Schuyler S. Korban ◽

Wannasiri Wannarat ◽

Charlotte M. Rayburn ◽

Tatiana C. Tatum ◽

A. Lane Rayburn

Keyword(s):

Genome Size ◽

Flow Cytometric Analysis ◽

Internal Standard ◽

The United States ◽

Mean Value ◽

Ploidy Levels ◽

Flow Cytometric ◽

Malus Species ◽

Leaf Tissues ◽

Stomatal Length

The genus Malus has anywhere between 25 and 33 species along with several subspecies. Malus species as well as clones within the same species have varying ploidy levels, as these are more than likely collected from different trees and (or) from different locations. In recent years, large numbers of Malus germplasm accessions have been collected and maintained at the United States National Germplasm Clonal Repository; however, genome sizes of this material have not yet been determined. In this study, leaf tissues from young grafted trees of 100 Malus species and hybrids growing in a nursery at the University of Illinois were collected and immediately used for extracting nuclei. Leaf tissues from apple and maize line W-22, used as an internal standard, were co-chopped and prepared for flow cytometric analysis. Apple nuclei were stained with propidium iodide, an intercalating dye, and a minimum of 8000 nuclei per sample were analyzed. Mean fluorescence of apple nuclei was then determined. A total of four replications per sample was used. Among 100 Malus accessions analyzed, one tetraploid, three triploid, and 96 diploid genotypes were identified. Significant differences in genome size were identified among the three ploidy types observed and also within diploid genotypes. The 2C mean value for tetraploids was 3.13 pg and ranged from 2.27 to 2.41 pg for triploids, whereas 2C values for diploids ranged between 1.44 and 1.72 pg. In addition, leaf impressions of young, fully expanded leaves were collected from young trees of 10 selected genotypes based on their ploidy and flow cytometric analysis and used to measure the nucleotypic parameter stomatal length. Ten stomata were measured per slide, three slides were analyzed per leaf, and three leaves were analyzed per accession. Overall, mean length of stomata ranged between 19.47 μm (diploid) and 27.6 μm (tetraploid), indicating that stomatal length in a tetraploid Malus genotype was 1.4-fold higher than that of a diploid genotype. A positive correlation between genome size and the nucleotypic parameter stomatal length was observed.

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