Meadowfoam (Limnanthes alba Bentham; Order: Brassicales; Family:
Limnanthaceae) is a self-compatible, predominantly allogamous, insect pollinated
species. Meadowfoam oil is a source of novel unsaturated very-long-chain (VLC) seed
oils (C������ and C������) with low concentrations of saturated fatty acids (typically less than
2%) and outstanding oxidative stability. Here we report the development of 389 SSR
markers for meadowfoam. All the 389 SSRs were screened on 14 meadowfoam
germplasm accessions to assess their utility and efficiency. Ninety-six percent of the
SSR markers (373 out of 389) were polymorphic among the 14-germplasm accessions
(from nine taxa) with a mean heterozygosity of 0.63.
We also report that the physical size of the meadowfoam genome was
estimated to be 5.52 pg using flow cytometry; thus, the meadowfoam genome is ca. 16
times larger than the Arabidopsis genome. Karyotype analyses revealed that the
meadowfoam genome is made up of two metacentric and three submetacentric
chromosomes. Meadowfoam has two pairs of chromosomes with subterminal
nucleolar organizing regions (NOR's). A genetic map comprised of 84 SSR loci
dispersed among five linkage groups with 11 to 22 SSR loci per linkage (6 SSR loci
segregated independently) was constructed. The map was 988.7 cM long with a mean
density of 11.8 cM and minimal clustering of loci.
A total of 20 quantitative trait loci (QTL) were identified for five mating
system characters in meadowfoam, using the SSR linkage map of meadowfoam.
Individual QTL for mating system traits peta1 area (pa), seeds per plant (spp) and
seeds per flower (spf)I account for up to 20% of the backcross phenotypic variance,
with most traits showing QTL effects of 5-15%. The QTL for protandry and chiasma
frequency were adjacent to the QTL for spp and spf. This study has provided evidence
that the correlation between the chiasma frequency and the type of mating system is
not a direct developmental relationship between these factors, but is due to a selective
advantage of the combination of the characters found. The speculation that the genetic
factors underlying chiasma frequency and autonomous seed set have co-evolved
during evolution negates the self-fertilization as an "evolutionary dead end". / Graduation date: 2002
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32553 |
| Date | 21 March 2002 |
| Creators | Kishore, Venkata Krishna |
| Contributors | Knapp, Steven J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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