Application of GISH to characterise Buddleja and Hibiscus hybrids

Genomic In Situ Hybridization (GISH) is a powerful technique for detecting parental origin of interspecific hybrids and monitoring alien chromatin introgressed in breeding lines. In this study, successful use of GISH for woody ornamentals, characterized by a small genome and high numbers of small-sized chromosomes, is demonstrated. GISH was performed on Buddleja and Hibiscus hybrids resulting from an interspecific breeding program between different species of both genera. Using B. globosa as a probe, GISH analyses on Buddleja ×weyeriana (a F2 of B. globosa × B. davidii) and F1 and F2 hybrids of B. davidii × B. ×weyeriana crosses proved that all chromatin material of B. globosa was introgressed into the B. davidii chromosomes. Also F2 hybrids of H. syriacus × H. paramutabilis were analysed using GISH with H. syriacus as a probe. Also here recombinant chromosomes showing introgression of H. syriacus DNA in H. paramutabilis were detected.