III. Current linkage maps

Construction of high-density linkage maps has been nearly completed based on the sequenced DNA fragments (RFLP) and RAPD markers by the staff of the Rice Genome Research Program (RGP) in Japan (Ref. Rice Genome 1994). In other RFLP maps constructed by the Cornell University group, over 700 markers have been mapped together with economically important genes. The following genes for agronomic traits are already tagged in both maps.

     Map of Rice Genome Program (Ref.  1 and 4)
     Xa-1 (Xanthomonas campestris pv.  oryzae resistance-1), Se-1
     (Photosensitivity-1), eg (extra glume), Ph (Phenol staining), Rc (Red
     pericarp), and Gm-2 (Gall midge resistance-2).

     Map of Cornell Univ. (Ref. 2, 3 and 5)
     S-6'(Hybrid sterility-6), sd-1 (dee-geo-woo-gen dwarf), xa-5
     (Xanthomonas campestris pv.  oryzae resistance-5), Wph-1 (white-backed
      planthopper resistance), Glh (Green leafhopper resistance), RTSV (Rice 
      tungro spherical virus resistance), and four kinds of Pi and 11 OTLs for
      blast resistance.
Plant materials such as recombinant inbred lines, backcross inbred lines and near isogenic lines are in preparation in both groups for gene tagging and molecular marker-aided selection. Microsatellite markers are also being developed to be used for the evaluation of closely related germplasms.

International cooperation for gene mapping is in progress as witnessed by the collaborative research between RGP and IRRI scientists.

References

1. Kurata, N., Y. Nagamura, A. Miyao, K. Yamamoto, M. Yano, Y. Minobe and T. Sasaki, 1994. Progress in CDNA analysis and construction of genetic physical maps in RGP. 4th International Workshop on Rice Molecular Biology, August, 1994, p.2-3. Tokyo.

2. McCouch, S. R., Y. G. Cho, O. Panaud, S. Yanagihara, E. Paul and S. Harrington, 1994. Rice genome analysis and rice improvement. 4th International Workshop on Rice Molecular Biology, August, 1994, p.4. Tokyo.

3. Nelson, R. J. 1994. Mapping and phenotypic characterization of genes for disease resistance. 4th International Workshop on Rice Molecular Biology, August, 1994, p.44. Tokyo.

4. 'Rice Genome' 1994. Published by Rice Genome Research Program (RGP) Vol. 2. No. 1. p.4. 5. Wang, G. L., D. J. Mackill, M. Bonman, S. R. McCouch, M. C. Champoux and R. J. Nelson, 1994. RFLP mapping of genes conferring complete and partial resistance to blast in a durably resistant rice cultivar. Genetics 136: 1421-1434.

Correction of errata in Vol. 10

P.20, last line (Dm-1), Reference 10:57-10:60

P.22, 6th line from top (Gdh-1), Reference 10: 21-10:23