Plant Genome II Conference
Town & Country Conference Center, San Diego, CA, January, 1994.
PG-II: HIGH RESOLUTION MAPPING OF RFLP MARKERS TIGHTLY LINKED TO THE
BARLEY YELLOW DWARF VIRUS RESISTANCE GENE YD2 ON CHROMOSOME 3 OF
BARLEY
HIGH RESOLUTION MAPPING OF RFLP MARKERS TIGHTLY LINKED TO THE
BARLEY YELLOW DWARF VIRUS RESISTANCE GENE YD2 ON CHROMOSOME 3 OF
BARLEY.
Nick Collins, Robert H. Symons, Department of Plant Science,
Waite Campus, University of Adelaide, Glen Osmond, South
Australia 5064.
Barley yellow dwarf virus (BYDV) infects all cereal types
including wheat, rice and maize and is the most destructive virus
of cereals worldwide. The Yd2 gene from several Ethiopian
barleys provides the only effective resistance to BYDV in
cultivated barley varieties. Isolation of the Yd2 gene would
facilitate understanding of the molecular basis of the Yd2/BYDV
interaction and would allow production of BYDV resistant cereal
varieties by transformation. It is our aim to create an RFLP map
of the Yd2 region of barley chromosome 3 which has a high enough
density and resolution to facilitate a map-based approach to
cloning Yd2. The morphological markers 'white stripe,,j' and
'uzu dwarf' are placed 10 centimorgans apart on either side of
Yd2 and are being used for construction of a high resolution RFLP
map. Of 1200 F2 individuals screened visually at the early
seedling stage, 120 recombinants were selected for further
analysis. The collection of recombinants, representing an
average of one crossover every 0.083 centimorgans will be
invaluable for ordering RFLP markers tightly clustered around
Yd2, particularly during a chromosome walk to Yd2. From a screen
of 65 group 3 probes, 19 markers have been shown to be closely
linked to Yd2 using 3 pairs of barley varieties which are near-
isogenic for Yd2. These markers will provide the basis for the
RFLP map.
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