'Plant Breeding: Sustaining the Future' Abstracts of the XVIth EUCARPIA Congress, Edinburgh, Scotland, 10-14 September 2001 ANALYSIS OF RYE GENETIC MAPPING POPULATIONS   J.P. GUSTAFSON, J.W. SNAPE USDA-ARS, University of Missouri, Columbia, Missouri 65211 USA

In rye, (Secale cereale L.), five different populations of have been used, separately, to create genetic linkage maps.  In total, more than 500 molecular markers and genes have been mapped to the various populations. The present study utilized these five data sets, from the F2 populations, 'UC90' X 'E-line', 'P87' X 'P105', 'Danko' x 'Halo', 'E-line' x 'R-line', and 'Ds2' x'RxL10' obtained from Ma et al. (2001), Korzun et al. (1998), Philipp et al. (1994), Loarce et al. (1996), and Devos et al. (1993), respectively, to develop a consensus map.  The integration of the five linkage maps using the computer software program JOINMAP 2.0 was only possible where at least two markers were common and located to each arm of each chromosome. The integration of the five mapping populations resulted in a map containing 503 markers (ranging from 57 on 1R to 86 on 4R) and covers 763.2 cM (ranging from 71.5 cM on 2R to 148.7 cM on 4R).  Analysis of the data indicated that many of the large recombinational gaps were consistent from population to population indicating that the gaps in rye are real and occur within a wide range of germplasm.  In addition to recombinational gaps, some clustering of markers was also noted, indicating the potential for gene clustering within rye.  The comparison of the individual maps to the consensus map revealed that the linear marker order was generally in good agreement between the various populations.  There was some reordering of segments of individual maps, but this reordering could be due to inversions or translocations between the parents of the various populations.  The general conservation of the linear marker order indicates a high degree of reliability in linkage map marker order within rye.  It appears, however, that there is more suppression of recombination at the centromere than previously thought.