GrainGenes

II. 29. Localization on barley chromosome 5 of the locus Pgd2 coding for phosphogluconate dehydrogenase.

Gunnar Nielsen, Hanne Johansen and Jens Jensen, Agricultural Research Department, Risø National Laboratory, DK-4000 Roskilde, Denmark.

The locus Pgd2 has previously been located on the long arm of chromosome 5 by telotrisomics (Nielsen 1982). In order to localize Pgd2 within the chromosome, three crosses involving several marker genes were made. The parents and their marker genes are shown in Table 1. It has not yet been possible to score all the plants for b and trd so two-point segregations are the recombination percentages estimated by the method of maximum likelihood given in Table 2 are preliminary. The close linkage of Pgd2 with wst5 confirms the previously reported location of Pgd2 on the long arm of chromosome 5. The locus order necl, wst5, Pgd2, B, tr, trd suggested by the recombination percentages, as well as most of the recombination percentages, are in agreement with the recently revised linkage map of chromosome 5 (Jensen 1983). The bad fit of the recombination percentages, involving b and trd, to the map of chromosome 5 is expected to be better when all the plants can be scored.

Table 1. The marker gene lines used as parent in the crosses.

Table 2. F2 two-point segregation data and recombination percentages involving Pgd2 and five other loci on chromosome 5L in the two three-point and four-point crosses.

References:

Jensen, J. 1983. Coordinator's report: Chromosome 5. BGN 13:94-97.

Nielsen, G. 1982. Supplementary and new evidence on the location of five enzyme loci on barley chromosome. BGN 12:68-69.

BGN 13 toc
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