A linkage map of spring turnip rape based on RFLP and HARD markers

Abstract

A linkage map of spring turnip rape (Brassica rapa ssp. oleifera) was conslructed from an F2 population of a cross Jo4002 x Sv3402. The map contained 22 RFLP loci, 144 RAPDs, one microsatellite, and one morphological marker (seed colour). All ten B.rapa linkage groups could be identified and the total map distance was 519 cM. A proportion of the markers (13%), most of which were located in two linkage groups, showed segregation distortion.

Identification and mapping of resistance gene analogs and a white rust resistance locus in Brassica rapa ssp. oleifera

“…The first seven and last six amino acids were contributed by the degenerate primer sequences. Amino acid motifs according to Meyers et al (1999) are marked at the top of the sequence (Tanhuanpää et al 1996); wr, population segregating for white rust resistance c Includes an insertion causing a frameshift d Includes a stop codon Fig. 3 The position of RGAs and RPS2 in the linkage groups constructed from the F 2 population of a B. rapa ssp.…”

“…The F 2 mapping population, which was previously used for creating a linkage map and, in this study, for locating the RGAs, originated from a cross between two individuals of repeatedly selfed spring turnip rape lines Jo4002 and Sv3402 (Tanhuanpää et al 1996).…”

“…The probes included purified plasmid DNA of each RGA class and one genomic Brassica DNA clone (WG6C1A) from Dr. T. Osborn (University of Wisconsin-Madison). The RGAs were located, whenever possible, on both the current and previously created linkage map of spring turnip rape (Tanhuanpää et al 1996). One microsatellite marker, 35D (Szewc-McFadden et al 1996), was amplified by PCR and visualized with the A.L.F.…”

“…RAPD primers were purchased from Operon Technologies (Alameda, Calif.) (denoted with a letter and a number) or synthesized (denoted with a number only) (primer sequences in Tanhuanpää et al 1996) on an Applied Biosystems 392 DNA/RNA synthesizer (Foster City, Calif.). The PCR protocol that yielded the best results consisted of 40 cycles of 30 s at 95C, 30 s at 35C and 2 min at 72C in a Mastercycler thermal cycler; this was preceded by an initial denaturation step of 3 min 30 s at 95C.…”

“…Several approaches were taken: BSA with random amplified polymorphic DNA (RAPD) markers, creation of a linkage map and candidate gene (RGAs) analysis. A secondary aim was to also map the RGAs found on the previously created linkage map of B. rapa (Tanhuanpää et al 1996).…”