Microsatellite and flow cytometry analysis to help understand the origin of Dioscorea alata polyploids
∙ Background and Aims Dioscorea alata is a polyploid species with a ploidy level ranging from diploid (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...
Saved in:
| Published in: | Annals of botany Vol. 112; no. 5; pp. 811 - 819 |
|---|---|
| Main Authors: | , , , , , |
| Format: | Journal Article |
| Language: | English |
| Published: |
England
Oxford University
01-09-2013
Oxford University Press (OUP) Oxford University Press |
| Subjects: | |
| Online Access: | Get full text |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | ∙ Background and Aims Dioscorea alata is a polyploid species with a ploidy level ranging from diploid (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 study was to use flow cytometry and microsatellite markers 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. Flow cytometry 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. |
|---|---|
| Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 PMCID: PMC3747798 |
| ISSN: | 0305-7364 1095-8290 |
| DOI: | 10.1093/aob/mct145 |