ANALYSES OF SOLANACEOUS SPECIES USING REPETITIVE GENOMIC DNA-SEQUENCES ISOLATED FROM SOLANUM BREVIDENS

The relationship between 22 potato species (Solanum spp.) and a range of other solanaceous species (S. melongena, S. dulcamara, Lycopersicon esculentum, Capsicum annuum, Nicotiana tabacum was examined using dot blot hybridization of two probes (pSB1 and pSB7) isolated from Solanu m brevidens CPC 2451. Under the most stringent washing conditions, the probes hybridized exclusively with the species from the series Etuber osa (S. brevidens, S. etuberosum and S. fernandezianum). Under less st ringent washing conditions hybridization to a larger number of species was observed with both probes. pSB7, but not pSB1, gave a signal in L . esculentum under the least stringent conditions, whereas neither pro be hybridized with C. annuum, S. melongena nor N. tabacum. An unweight ed logistic regression model was used for estimating the order and dis tance of each species from S. brevidens CPC 2451. With pSB1, all speci es differed from S. brevidens CPC 2451 (P = 0.0000-0.0035), and the Et uberosa group differed from the tuber-bearing species (P < 0.0001). Th e order of species was similar with pSB1 and pSB7, but the P values we re not significant with pSB7, indicating less specificity of pSB7 to S . brevidens CPC 2451.