Microsatellite genotyping of carnation varieties.

A set of 11 sequence-tagged microsatellite markers for carnation (Dianthus caryophyllus) was developed using a DNA library enriched for microsatellites. Supplemented with three markers derived from sequence database entries, these were used to genotype carnation varieties using a semi-automated fluorescence-based approach. In a set of 82 cultivars, the markers amplified 4-16 alleles each. The effective number of alleles varied from 1.9 to 6.0. For the eight best scorable markers, heterozygosity was between 0.51 and 0.99. The markers were able to distinguish all cultivars with a unique combination of alleles, except for sport mutants, which were readily grouped together with the original cultivar. In addition, one group of three and one group of six cultivars each had the same combination of 'allelic peaks'. The cluster of three varieties concerned original cultivars and their mutants. The cluster of six consisted of four mutants from the same cultivar and two other varieties.

Construction and testing of a microsatellite database containing more than 500 tomato varieties.

The aim of this study was to evaluate the suitability of sequence tagged microsatellite site (STMS) markers for varietal identification and discrimination in tomato. For this purpose, a set of 20 STMS primer pairs was used to construct a database containing the molecular description of the most common varieties (>500) of tomato grown in Europe. The database was built and tested by a consortium of five European laboratories each using a different STMS detection system. In this way, it could be demonstrated that the STMS markers and database were suitable for use in network activities where a common database is being established on a continuing basis with data from different laboratories.Microsatellite polymorphism in tomato was found to be relatively low. The number of alleles per locus ranged from 2 to 8 with an average of 4.7 alleles per locus. Nevertheless, more than 90% of the varieties had different microsatellite profiles. A "blind testing" exercise showed that in general, identification of unknown samples (or detecting the most similar variety) with the 20 markers and the database was relatively easy for homogeneous varieties but less certain with heterogeneous varieties when using pools of 6 individuals.