e-journal

Microsatellite and flow cytometry analysis to help understand the origin of Dioscorea alata polyploids

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† Background and Aims:
Dioscorea alata is a polyploid specieswith a ploidy level rangingfromdiploid(2n = 2x = 40) to tetraploid (2n = 4x = 80). Ploidy increase is correlated with better agronomic performance. The lack of knowledge about the origin of D. alata spontaneous polyploids (triploids and tetraploids) limits the efficiency of polyploid breeding. The objective of the present studywas to use flowcytometry andmicrosatellitemarkers to understand the origin of D. alata polyploids.

† Methods:
Different progeny generated by intracytotype crosses (2x × 2x) and intercytotype crosses (2x × 4x and 3x × 2x) were analysed in order to understand endosperm incompatibility phenomena and gamete origins via the
heterozygosity rate transmitted to progeny.

† Results:
This work shows that in a 2x × 2x cross, triploids with viable seeds are obtained only via a phenomenon of
diploid female non-gametic reduction. The study of the transmission of heterozygosity made it possible to exclude polyspermy and polyembryony as the mechanisms at the origin of triploids. The fact that no seedlings were obtained by a 3x × 2x cross made it possible to confirm the sterility of triploid females. Flowcytometry analyses carried out on the endosperm of seeds resulting from 2x × 4x crosses revealed endosperm incompatibility phenomena.

†Conclusions:
The major conclusion is that the polyploids of D. alata would have appeared through the formation of
unreduced gametes. The triploid pool would have been built and diversified through the formation of 2n gametes in diploid females as the result of the non-viability of seeds resulting from the formation of 2n sperm and of the nonviability of intercytotype crosses. The tetraploids would have appeared through bilateral sexual polyploidization via the union of two unreduced gametes due to the sterility of triploids.

Key words: Dioscorea alata, endosperm balance, 2n gametes, bilateral sexual polyploidization, triploid origin, polyploidy.

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Informasi Detail

Judul Seri

Annals of Botany

No. Panggil

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Penerbit

Oxford : Oxford University Press on behalf of the Annals of Botany Company., 2013

Deskripsi Fisik

Annals of Botany 112: 811–819, 2013

Bahasa

English

ISBN/ISSN

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Klasifikasi

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Tipe Isi

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Tipe Media

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Tipe Pembawa

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Edisi

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Subjek

FISIOLOGI TANAMAN

Info Detail Spesifik

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Pernyataan Tanggungjawab

agus

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