Diversity between and within farmers’ varieties of tomato from Eritrea
Tomato yields in Eritrea are low (15 Mg/ha) compared with 19 Mg/ha in Africa and 27 Mg/ha worldwide. This is partly caused by poor quality of varieties used. This study analysed the diversity among and heterogeneity within farmers’ varieties of tomato from Eritrea and compared these varieties with other African and Italian varieties. Fifteen simple sequence repeat (SSR) markers were used for the genetic analysis. Genetic similarities among the varieties were calculated and an Unweighted Pair Group Method with Arithmetic Mean analysis was performed. Furthermore, individual plants of varieties were genotyped to evaluate uniformity within varieties. A high degree of diversity was observed among the Eritrean varieties. Thirteen out of the 15 SSRs were polymorphic, with 2 to 5 alleles per marker. The dendrogram showed two major types of varieties: San-Marzano and Marglob. Eritrean varieties were closely related to old Italian varieties in both types. Analysis of the within-variety variation showed that the Eritrean tomato genotypes were less uniform than the other varieties, probably because of deliberate mixing. A survey among farmers showed that some of them purposely mixed seeds to prolong the harvesting period, for yield stability and stress tolerance. Farmers value ‘new material’ as a source of influx.
Key words: Farmers’ varieties, genetic diversity, genetic purity, rapid ruralappraisal, Solanum lycopersicum, seed mixing, seed systems, simple sequence repeat.