Plant Genome I Conference
Town & Country Conference Center, San Diego, CA, November, 1992.
PG-I: 3pg1
RFLP MAPPING OF QUANTITATIVE TRAIT LOCI FOR GRAIN PROTEIN
CONTENT IN WHEAT.
K.S. Aitken, P.L. Jack 1 and J. W. Snape, Cambridge Laboratory,
Colney Lane, Norwich, 1 Plant Breeding International, Cambridge.
The genetic control of grain protein amount in wheat is
known to be quantitative and strongly influenced by environmental
factors. For these reasons breeding wheat varieties with high
grain protein has proved difficult. However, molecular markers
can now provide a means of mapping the quantitative trait loci
involved. By first using chromosome assays we have shown the
importance of genes on the homoeologous group 5 chromosomes in
increasing grain protein. The 5D loci appear to have the
greatest effect, although both the 5A and 5B loci have been
implicated. To map these loci, single chromosome recombinant
lines for the 5A and the 5D chromosomes were produced between a
low protein and a high protein wheat variety. Phenotypic
assessment showed that the 5D lines had a bimodal distribution
indicating a single QTL of major effect on grain protein content.
Molecular markers were obtained and screened against a number of
enzymes on the high and low grain protein wheat varieties. These
chromosomes were found to have a very low level of polymorphism,
with the 5D chromosome the least polymorphic and the 5B the most.
The polymorphic clones have been used to produce a map of the 5A
and 5D chromosomes using the single chromosome recombinant lines.
This is now being combined with the protein data to identify the
location of the putative high protein content QTLs on these
chromosomes.
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