The cultivated sunflower (Helianthus annuus L., x=17) is one of the most important
annual oilseed crops in the world. There are very few publicly shared sequence-based
DNA markers and genetic maps in sunflower, even though molecular DNA markers
and genetic maps have become widely used in all areas of genetic research and
breeding in plant species. The objectives of this study were to develop sequence-based
molecular markers and utilize the markers for genetic analyses and constructing
maps in the cultivated sunflower. A total of 131 functional simple sequence repeat
(SSR) markers were developed for 16 elite inbred lines using a small insert genomic
library enriched for short simple sequence repeats. The polymorphism information
content (PIC) estimated from 74 polymorphic SSR markers ranged from 0.0 to 0.93
with mean value of 0.55. Tetranucleotide repeats were significantly more
polymorphic than dinucleotide and trinucleotide repeats, and no obvious correlation
was found between repeat numbers and PIC scores. Genetic distance among 16 inbred lines, estimated from 74 polymorphic SSR markers ranged 0.175 to 0.543. Principal
coordinate and cluster analyses of the genetic distance matrix well explained the
difference between oilseed lines and confectionery lines, and sterility maintainer lines
and fertility restorer lines. A total of 1,090 SSR markers were screened for
polymorphism between the parents of two mapping populations. The two genetic
maps were constructed by genotyping 94 recombinant inbred lines from a cross
between PHA and PHB (276 SSR loci covering 1377.4 cM with mean distance of 4.99
cM), and 94 F��� progeny from a cross between HA370 and HA372 (122 SSR loci
integrated into the existing RFLP framework map covering 1348.0 cM with mean
distance of 6.77 cM). Ninety-three percent of the SSR markers were mapped to single
loci and 56.5% of the loci were co-dominant. Clustering of SSR loci was observed
near centromeric regions and most of the distorted loci were mapped to centromeric or
distal regions. A concerted effort to develop SSR markers and generate highresolution
SSR maps will enhance future fingerprinting analyses, fine-scale genome
analyses and molecular breeding in the cultivated sunflower. / Graduation date: 2002
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32415 |
| Date | 07 September 2001 |
| Creators | Yu, Ju-Kyung |
| Contributors | Knapp, Steven J. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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