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Abstracts
K. Tsunewaki (Dept. Biosci., Fukui Pref. Univ.)
Trends in wheat genetics
Development of genome analysis (or polyploid genetics), aneuploid
genetics, cytoplasmic genetics
and molecular genetics in wheat after the corresponding epoch-making
discovery was reviewed, and the contributions of these fields to our
understanding of wheat evolution and to wheat breeding were
mentioned. Genome analysis clarified the interspecific relationship
in the Triticum and Aegilops complex, and stimulated
triticale breeding. Aneuploid genetics contributed in establishing
the homoeology first between the chromosomes then between the genes.
At the same time, it facilitated the development of various means of
chromosome manipulation. Comparative gene analysis of common wheat
and its ancestors, that was facilitated by the use of aneuploid
methods of gene analysis, yielded rich information on the
phylogenetic differentiation and origin of polyploid wheats.
Cytoplasmic genetics, represented by the plasmon analysis, allowed
the determination of maternal lineage of the polyploids on one hand
and stimulated hybrid wheat breeding on the other. The newest field
of molecular genetics already achieved construction of the synteny
map of cereal chromosomes, and steady development of biotechnology is
now apparent through integration of various in vitro culture
techniques and DNA delivery methods. Then the perspective of wheat
genetics was discussed, pointing out the followings as the important
problems, unsolved or remained; (1) need of unification of
taxonomical system and genome symbol, (2) molecular mechanism of the
homologous chromosome pairing, (3) origin of the clusters of modified
genomes at the diploid level, (4) amplification of the repeated
sequences in specific chromosomes and genomes, (5) molecular changes
in genes which are closely related to wheat domestication, (6) entire
structure and function of the complex loci, (7) targeting a gene to a
specific chromosome site and to a specific organelle, and (8)
regeneration of wheat plant from the protoplast.
T. Takeda (Res. Inst. Bioresources, Okayama Univ.)
Genetical studies in barley
In 1949's Dr. R. Takahashi started genetical studies in barley at
the Ohara Institute of Agriculture. For this half century he and his
successors continued their efforts to collect barley germplasm and to
analyze the phylogeny and genetical constitution of the materials. At
present we keep ca. 10,000 barley accessions including wild
relatives, local varieties, mutants, isogenic lines, linkage testers,
trisomics, tetraploids, doubled haploids, recombinant inbreds,
wheat-barley addition lines etc. In this symposium I will introduce a
histry of barley genetic study in our Institute, an outline of the
germplasm collection, and some topics on the stress tolerance of
barley and QTL analysis of the agronomic traits.
A. Kilian1 and A. Kleinhofs2
(1Dept. Crop & Soil Sci. and 2Dept. Genetics and Cell
Biol., Washington State Univ.)
Fine mapping of barley Rpg1 region by using rice-barley
microsynteny
The barley stem rust resistance genes Rpg1 and rpg4
were mapped in barley on chromosomes
1P and 7M, respectively and syntenous rice chromosomes identified as
6P and 3P by mapping common probes in barley and rice. Rice yeast
artificial chromosome (BAC), bacterial artificial chromosome (BAC)
and cosmid clones were used to isolate probes mapping to the barley
Rpg1 region.
A high resolution map of the
Rpg1 region was established with 1400 gametes yielding a map
density of 3.6 markers per 0.1 cM. These experiments confirm the
validity of using large insert rice clones as probe sources for
saturation mapping in large genome cereals.
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