Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 38pg1
MAPPING THE A AND C GENOMES OF THE GENUS BRASSICA: A PROGRESS
REPORT
J. Hu, S. Kianian, M. McGrath, P. Arus and C. F. Quiros,
Department of Vegetable Crops, University of California, Davis,
CA 95616
The genus Brassica embodies numerous important crop species
grown as oilseeds, vegetables, fodder and sources of condiments.
Our Brassica research projects have produced genetic maps for
each of the A (B. rapa, syn. campestris, n=10), B (B. nigra, n=8,
see separate poster by Truco and Quiros) and C (B. oleracea, n=9)
genomes. The A genome map, constructed from an F2 population,
consists of 3 isozyme and 32 RFLP markers in 10 groups. Both
linkage and synteny maps have been constructed for the C genome.
The linkage map was generated from four segregating populations
(3 intraspecific and 1 interspecific crosses). It comprises 112
markers (3 morphological, 4 isozyme 101 RFLP and 4 RAPD) spread
in 9 groups and covering 715 cM. The synteny map is based on B.
rapa-oleracea alien chromosome addition lines extracted from both
natural and artificial B. napus. A total of 181 markers (1
morphological, 4 isozyme, 77 RFLP and 99 RAPD) have been located
on 9 chromosomes using 8 monosomic addition lines. The synteny
map could be used to assign the linkage groups to specific
chromosomes. We have found that sequence duplication is an
important feature of the Brassica genomes. Currently, we are
consolidating our maps with those of two other laboratories, B.
Landry's (B. oleracea) and R. Bernatzky's (B. rapa). As an
application of these maps, we will use the information from the
diploid species to locate QTL in the amphidiploid species, B.
napus, using the F3 progenies derived from segregating F2
individuals that are already characterized for fatty acid
compositions,in collaboration with D. Struss and G. Robbelen at
the University of Gottingen, Germany.
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