Development Of Radish-specific DNA Markers To Recognize R-genomic Components In Raphanobrassica And Define The Genetic Linkage Groups Using Markers Assigned To Raphanus Chromosomes A-I

Molecular linkage groups are essentially the map of chromosomes on DNA level, thus each linkage group should be corresponding individually to each chromosome. This work was carried out to develop molecular markers special for Raphanus sativus chromosomes in Raphanobrassica, to map them on linkage groups as well as to localize the anchor markers with known assignment to the nine radish chromosomes, so as to define each linkage group with assigned markers for each chromosome of Raphanus sativus .According to the series of rape-radish addition lines and their corresponding Raphanus chromosomes, it's clear to determine the specific molecular markers for each chromosome of Raphanus from A to I. As a result, 413 (71.7%) which were screened from 581 primers(or primer combinations) amplified altogether 899 RAPD markers special for all 9 radish chromosomes, and 116 of them were polypmorphic between the radish parents (nematode-resistant and nematode-susceptible respectively). And 29 of them were mapped in 245 F2 population. Of the 29 anchor loci specifying all nine radish chromosomes A to I in rape-radish chromosome additions, 18 assigned markers were mapped into the 9 linkage groups, linkage groups 1, 2, 3, 4, 5, 6, 7, 8, 9 is corresponding to chromosomes A, F, I, E, G, H, D, C, B, respectively.It could be proven that linkage group 7 carrying the QTLHsl~Raph for nematode resistance in fodder radish( which has been determined by Dr. Magdi from the same program) corresponds with the resistance-bearing chromosome D of the rape-radish chromosome addition( which has been detected by Dr. Peterka et al. from the same lab.). The known linkage distances of the chromosome D markers to QTL HsI~Raph will be useful to search for intergenomic recombinations in a program intended to introgress nematode resistance from radish to other Brassicae crops using chromosome addition. And this Raphanus sativus map can be used for mapping further resistance traits in radish.