Coordinator's report: Chromosome 5

Jens Jensen
Agricultural Research Department
Risø National Laboratory
DK-4000 Roskilde, Denmark

Based on six crosses (Jensen, 1990), it was shown that the powdery mildew resistance locus Ml-pis not located on chromosome 5. It was also indicated that no support exists for powdery mildew resistance locus ml-d is located on chromosome 5.

Therefore, in addition to locus Ml-p, which was previously removed from the linkage map of chromosome 5 (BGN 17), the ml-d locus has now also been removed. The recombination frequencies between marker loci supporting the above conclusion, and some additional ones reported by Jensen (1990) are shown in Table 1. The additional recommendation estimates are utilized to improve the chromosome 5 linkage map (Fig. 1) using the procedure described by Jensen and Jørgensen (1975).

Fig. 1.Linkage map of chromosome 3 in barley based on the data obtained by Takahashi and his co-workers. The map distances are given in centimorgans (cM).

Table 1. Linkage data reported by Jensen (1990).

References:

Jensen, J. 1990. Are powdery mildew loci MI-p and ml-d on barley chromosome 5? BGN 19:27-32.

Jensen, J., and J. H. Jørgensen. 1975. The barley chromosome 5 linkage map. I. Literature survey and map estimation procedure. Hereditas 80:5-16.

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