ISHS Acta Horticulturae 510: VII Eucarpia Meeting on Cucurbit Genetics and Breeding
TOWARDS AN INTEGRATED LINKAGE MAP OF CUCUMBER: MAP MERGING |
| Authors: | Jack E. Staub, Felix C. Serquen |
| Keywords: | genetic maps, isozymes, RFLPs, RAPDs, morphological traits, disease resistance |
| Abstract:
Linkage maps in cucumber (Cucumis sativus) have been constructed using morphological traits, isozymes, restriction fragment length polymorphisms (RFLPs), and random amplified polymorphic DNAs (RAPDs). The lack of polymorphism in cucumber has led to the construction of relatively unsaturated maps (13 to 80 points). We have used the computer programs MapMaker v. 1.0 and JoinMap v. 1.0 to construct and join the map of Fanourakis and Simon (1987), Knerr and Staub (1992), Kennard et al. (1994), and Meglic and Staub (1996). These map-merging experiments produced a 134-point narrow-based map consisting of morphological traits, disease-resistance loci, isozymes, RFLPs, and RAPDs spanning 431 cM having a mean interval distance of 3.2 cM. A second map was constructed using data from two relatively wide crosses in cucumber: GY-14 × PI 183967 and H-19 × G421 and produced a 147-point wide-based merged map spanning 458 cM where the mean marker interval was 3.1 cM. In some cases, single and flanking marker-trait relationships were relatively close (1 to 3 cM) in both consensus maps. Condensation of total distance occurred in merged maps compared to historic maps using the same markers. These maps represent the “best fit” of the data used, but difficulties were encountered when manipulating large data sets having missing values. Moreover, the two maps could not be merged because of a paucity of common anchor points. | |
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