The occurrence of seed-producing wheat x jointed goatgrass hybrids in
infested wheat fields suggests the possibility of gene flow between the two species.
This study investigates 'Madsen' wheat x jointed goatgrass F��� and reciprocal
backcross derivatives produced in experimental field plantings. Electrophoresis of the
high molecular weight (HMW) glutenin seed proteins, chromosome counts, and
morphological studies were used to better understand the genetics of these hybrids,
and to provide a baseline for evaluating hybrids collected in natural populations. The
HMW glutenin profiles are a useful diagnostic tool because the banding patterns, in
the 68-120 kDa molecular weight range, are species-unique (three bands for goatgrass,
four bands for wheat) and can be used to trace parentage in the hybrid seed on the
basis of band contribution. Experimental hybrids show considerable diversity in
banding profiles (9 patterns of three to six bands). Diversity in number of different
glutenin profiles and number of subunits per seed decreases in more advanced
generations (BC��� and BC���S���). Chromosome counts confirm the direction of the
crosses and vary as follows: 35 chromosomes for F���; 36 to 57 for BC���; 28 to 49 for
BC���; and 33 to 52 for BC���S���. A chromosome number of 28 suggests that jointed
goatgrass (2n=4x=28) was the recurrent backcross pollen donor, while numbers closer
to 42 and above point to wheat (2n=6x=42) as the pollen donor. Partial female fertility
was found in all generations, as well as full self-fertility in BC��� and BC���S��� plants.
Analysis of the HMW glutenin profiles of the progeny seeds verifies that hybridization
can go in either direction, with most banding patterns similar to either jointed
goatgrass or wheat. The resulting potential for gene flow from wheat to jointed
goatgrass calls for continued study of these hybrid derivatives. / Graduation date: 2001
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/32793 |
| Date | 20 November 2000 |
| Creators | Cr��mieux, Lis���ele |
| Contributors | Mallory-Smith, Carol A. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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