Meiosis and sexual fertility of autotetraploid clones of greater yam Dioscorea alata L.

Abraham, K.; Némorin, Alice; Lebot, Vincent; Arnau, Gemma

doi:10.1007/s10722-013-9973-4

Cited by 19 publications

(18 citation statements)

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“…Populations of mixed ploidy cannot be assessed using current statistical approaches ( Meirmans et al , 2018 ). As reported in previous studies and confirmed here, the natural frequency of diploid lineages outweighs the contribution of polyploids to diversity ( Abraham et al , 2013 ). Moreover, genetic diversity within the diploid gene pool well represented the overall diversity of the species as polyploids arise from diploids through unreduced gametes formation ( Nemorin et al , 2013 ).…”

Section: Resultssupporting

confidence: 91%

“…In traditional agrosystems, yams are cultivated exclusively through clonal propagation and selection of somaclonal mutants ( Vandenbroucke et al , 2016 ). Flowering is erratic or absent in many cultivars, but new combinations can still be obtained via residual sexual reproduction ( Abraham et al , 2013 ). Dioscorea alata is a dioecious, autopolyploid species (2 n = 2 x = 40, 3 x = 60 and 4 x = 80) ( Arnau et al , 2009 ), and triploids and tetraploids are the result of unreduced gametes ( Nemorin et al , 2013 ).…”

Section: Introductionmentioning

confidence: 99%

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Genome-wide genotyping elucidates the geographical diversification and dispersal of the polyploid and clonally propagated yam (Dioscorea alata)

et al. 2020

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Background and Aims Inferring the diffusion history of many human-dispersed species is still not straightforward due to unsolved past human migrations. The centre of diversification and routes of migration of the autopolyploid and clonally propagated greater yam, Dioscorea alata, one of the oldest edible tubers is still unsolved. Here, we address yam demographic and dispersal history using a worldwide sample. Methods We characterized genome-wide patterns of genetic variation by genotyping by sequencing 643 greater yam accessions spanning four continents. First, we disentangled the polyploid and clonal components of yam diversity using alleles frequency distribution and identity by descent approaches. Then, we addressed yam geographical origin and diffusion history with a model-based coalescent inferential approach. Key Results Diploid genotypes were more frequent than triploids and tetraploids in all the continents. Genetic diversity was generally low and clonality appeared to be a main factor of diversification. The most likely evolutionary scenario supported an early divergence of mainland Southeast Asian and Pacific gene pools with continuous migration between them. Triploids and tetraploids genetic make-up suggests that they have originated from these two regions before westward yam migration. The Indian Peninsula gene pool gave origin to the African gene pool, which was later introduced in the Caribbean region. Conclusions Our results are congruent with the hypothesis of independent domestication origins of the two main Asian and Pacific gene pools. The low genetic diversity and high clonality observed suggest a strong domestication bottleneck followed by thousands of years of widespread vegetative propagation and polyploidisation. Both processes reduced the extent of diversity available for breeding, which most likely threaten future adaptation.

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Genome-wide genotyping elucidates the geographical diversification and dispersal of the polyploid and clonally propagated yam (Dioscorea alata)

et al. 2020

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“…Higher vigour and tuber yield advantage were reported with tetraploid (2n = 80) and triploid (2n = 60) water yam compared to its diploid (2n = 40) counterpart (Arnau et al, ; Lebot, ). The positive effect of artificially induced polyploid on chlorophyll content, leaf shape, and stomata density, plant width, and fruit set has been reported in water yam (Abraham, Nemorin, & Lebot, ; Ajayi, Adesoye, Asiedu, & Sartie, ; Babil et al, ). Kenji, Ohara, and Iwasa () reported a shorter and thicker vine in D. japonica with artificially induced tetraploid.…”

Section: Innovative Methods Of Genetic Improvement In Yammentioning

confidence: 83%

Review of empirical and emerging breeding methods and tools for yam (Dioscorea spp.) improvement: Status and prospects

et al. 2019

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Yam (Dioscorea spp.) is an important tuber crop with tremendous potential as a functional food in the tropics and subtropics. However, the crop has not shown progressive productivity gain over decades due to various production constraints. This paper reviews the progress achieved in empirical breeding endeavours and the development, status and application of emerging breeding tools and technologies to translate genetic gains in yam improvement. Significant progress has been made in yam genetic improvement over the years which has led to the identification and development of several improved clones and sources of variability for various economically important traits. Substantial efforts have also been made to develop diverse molecular markers, transcriptome and metabolome profiles of crucial traits, trait mapping and generate reference genome sequences of the key species. However, there seems to be a slow translation of research improvements into widespread applications. These advances and the integration of empirical and emerging methods and technologies into the breeding process will enhance yam breeding efforts and ensure the quick delivery of improved varieties that possess superior agronomic and quality traits.

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“…Alternatively, an evolved autotetraploid state may feature a high rate of quadrivalent formation in metaphase I, indicating chiasma formation between more than two homologues (Bomblies et al 2016 ). For example, in various species from purple yam (Abraham et al 2013 ) to peavines (Khawaja et al 1997 ) and various grasses (Koul et al 1999 ; Deniz and Dogru 2006 ), quadrivalent formation at metaphase I reaches 20–47%. A more extreme example is cock’s foot, in which the chromosomes mostly form quadrivalents, and the chiasma frequency in evolved autotetraploids is higher than in the diploids or newly formed tetraploids (McCollum 1958 ).…”

Section: Introductionmentioning

confidence: 99%

Varietal variation and chromosome behaviour during meiosis in Solanum tuberosum

et al. 2020

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Naturally occurring autopolyploid species, such as the autotetraploid potato Solanum tuberosum, face a variety of challenges during meiosis. These include proper pairing, recombination and correct segregation of multiple homologous chromosomes, which can form complex multivalent configurations at metaphase I, and in turn alter allelic segregation ratios through double reduction. Here, we present a reference map of meiotic stages in diploid and tetraploid S. tuberosum using fluorescence in situ hybridisation (FISH) to differentiate individual meiotic chromosomes 1 and 2. A diploid-like behaviour at metaphase I involving bivalent configurations was predominant in all three tetraploid varieties. The crossover frequency per bivalent was significantly reduced in the tetraploids compared with a diploid variety, which likely indicates meiotic adaptation to the autotetraploid state. Nevertheless, bivalents were accompanied by a substantial frequency of multivalents, which varied by variety and by chromosome (7–48%). We identified possible sites of synaptic partner switching, leading to multivalent formation, and found potential defects in the polymerisation and/or maintenance of the synaptonemal complex in tetraploids. These findings demonstrate the rise of S. tuberosum as a model for autotetraploid meiotic recombination research and highlight constraints on meiotic chromosome configurations and chiasma frequencies as an important feature of an evolved autotetraploid meiosis.

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Meiosis and sexual fertility of autotetraploid clones of greater yam Dioscorea alata L.

Cited by 19 publications

References 18 publications

Genome-wide genotyping elucidates the geographical diversification and dispersal of the polyploid and clonally propagated yam (Dioscorea alata)

Genome-wide genotyping elucidates the geographical diversification and dispersal of the polyploid and clonally propagated yam (Dioscorea alata)

Review of empirical and emerging breeding methods and tools for yam (Dioscorea spp.) improvement: Status and prospects

Varietal variation and chromosome behaviour during meiosis in Solanum tuberosum

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