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Abstract Detail



Hybrids and Hybridization

Halbrook, Kandres [1], Smith, Steven [2], Lacey, Kathryn [1], Binney, Matthew [1], Leawna, Broduer [1], Benson, Mathew [1], Rigden, Colin [1].

Pseudogamous apomixis, relative ploidy, and fertility in Bouteloua curtipendula (POACEAE).

Most sexual angiosperms produce an endosperm with a ratio of 2 maternal to 1 paternal genomes (2Cm:1Cp). This ratio has been shown to be generally necessary for normal endosperm development and failure to achieve it often leads to seed abortion. Pseudogamous apomictic plants can produce an embryo without fertilization, but require fertilization to produce the endosperm. Aneuploidy in pseudogamous species may result in irregular meiosis and variable sperm chromosome numbers that may affect endosperm development and seed formation. We asked how one putative pseduogamous apomictic aneuploid species produces endosperm and whether there is a relationship between m:p contribution to the endosperm and grain set (fertility). We used flow cytometric seed screens to evaluate reproductive pathway, estimate embryo and sperm nucleus relative DNA content, calculate m:p endosperm ratios and then correlated these data with fertility in five populations of Bouteloua curtipendula var. caespitosa (Poaceae). We confirmed that this taxon is aneuploid and reproduces by pseudogamous apomixis. Endosperm ratios varied from 2Cm:1.7Cp to 2Cm:2.4Cp, but there was no relationship between mean endosperm ratio and fertility. However, accessions with higher fertility also had a larger number of grain that aborted early in development. Evidence suggests that maternal effects play a more prominent role in fertility than paternal effects and that paternal contribution to the endosperm, while necessary for grain formation, is not the primary factor determining grain production. The results of this study will help us better understand reproductive biology, and thereby population dynamics and evolution in apomictic species.

Broader Impacts:


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1 - University of Arizona, 325 Biological Sciences East, Tucson, AZ, 85721, USA
2 - University of Arizona, SCHOOL OF NATURAL RESOURCES, 325 BIO SCI EAST, 1311 E. 4th Street, Tucson, AZ, 85721, USA

Keywords:
aneuploidy
endosperm
flow cytometry
Polyploidy.

Presentation Type: Oral Paper:Papers for Topics
Session: 22
Location: Rosedown/Riverside Hilton
Date: Tuesday, July 30th, 2013
Time: 10:00 AM
Number: 22005
Abstract ID:787
Candidate for Awards:None


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