Cultivated meadowfoam (Limnanthes alba Benth.) is an annual oil seed crop
native to southern Oregon. California and British Columbia. The genus
Limnanthes is composed of nine species and divided into two sections, Inflexae and
Reflexae. The seed oil of meadowfoam is a rich source of erucic acid and several
novel very long-chain fatty acids (VLCs). The former has been linked to increased
risk of heart disease. The safe limit of erucic acid for human consumption is up to
5% of total fatty acids. Because the erucic acid concentrations of wildtype lines
typically range from 9 to 23% and low erucic acid variants have not been
discovered, chemical mutagenesis was used to develop a mutant line (LE76) with
greatly reduced erucic acid (3%). The phenotypic distributions of F��� progeny
from crosses between wildtype and mutant lines were continuous and differed
across genetic backgrounds. Quantitative trait loci (QTL) affecting erucic and
dienoic acid were mapped using F���:��� progeny from a cross between LE76 and
Wheeler (a wildtype line) and a simple sequence repeat (SSR) map spanning the
meadowfoam genome. The domestication of meadowfoam was based on L. alba,
belonging to section Inflexac. The secondary and tertiary gene pools have not been
important to the domestication process and have not supplied diversity for
meadowfoam breeding. With the objectives of introgressing genes from wild
relatives and also producing cytoplasmic male sterile lines by inserting the nuclear
genome of L. alba into wild cytoplasm, inter-sectional crosses involving L. alba
and three subspecies of L. douglasii and intra-sectional crosses involving L. alba
and two subspecies of L. floccosa were carried out. The isolation mechanisms
involved in keeping species apart from each other were found to be different within
and between sections. The study of partially fertile intra-sectional hybrids showed
that the reduced pollen viability (30-33%) was not due to structural differences
between the chromosomes of the two species, as normal meiotic behavior was
observed in PMCs. The inter-sectional crosses were found to be incompatible and
various abnormalities during pollen tube growth were observed. / Graduation date: 2002
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32485 |
| Date | 26 April 2002 |
| Creators | Gandhi, Sonali Dilip |
| Contributors | Knapp, Steven J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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