BIN MAPPING OF EST-SSRS IN APPLE (MALUS X DOMESTICA BORKH.)

The generation of a nearly saturated genetic map for apple based on microsatellites (simple sequence repeats, SSRs), provides the basis for the application of transferable genetic markers to a wide range of apple mapping populations.
However, while some 85% of the genome can be covered by a framework of markers spaced by 15 cM, there remain large regions without suitable markers; in addition, some markers have null alleles, or detect multiple loci, or have a few alleles, which will cause problems for future genetic mapping.
We have used the currently available EST databases to develop new EST-SSR markers in order to fill these gaps and ensure portability between a wider range of cultivars.
Two mapping populations, ‘Anna’ x ‘Golden Delicious’ and ‘Anna’ x ‘Sharpe’s Early’, have been used to generate genetic linkage maps with a desired separation of 15 cM between markers.
Sets of six, eight, and ten individuals were selected from these mapping populations in order to apply selective mapping, which allows for the rapid mapping of genetic markers to a low-resolution position on the genetic map.
Those markers that fill gaps in the genetic map can then be mapped at a higher level of resolution on the full mapping population.
The generation of new markers and the determination of their position on the genetic linkage map is an ongoing process and this paper describes the strategy followed in selecting markers for implementation on full mapping populations with the ultimate goal being expansion of genetic linkage maps.
The SSR markers used form part of a bigger project and their accession numbers and sequences will be reported on later as part of a larger set of markers.

XII EUCARPIA Symposium on Fruit Breeding and Genetics

M.M. van Dyk, D.J.G. Rees

genetic linkage map, map saturation, transferable markers

https://doi.org/10.17660/ActaHortic.2009.814.116