Proceedings of the XLVII Italian Society of Agricultural Genetics - SIGA Annual Congress

Verona, Italy - 24/27 September, 2003

ISBN 88-900622-4-X

Poster Abstract - 2.50

AFLP FINGERPRINTING OF DIPLOID MEXICAN SOLANUM SPECIES AND TETRAPLOID DERIVATIVES

R. AVERSANO, M. CARTOLANO, M.R. ERCOLANO, L. MONTI, L. FRUSCIANTE, D. CARPUTO

Dept. Soil, Plant and Environmental Sciences, University of Naples "Federico II", Portici, Italy

potato, Phytophthora infestans, somaclonal variation, cluster analysis

To introgress resistance to Phytophthora infestans into the cultivated gene pool, sources of resistance were identified in clones of diploid Mexican species S. bulbocastanum (blb), S. cardiophyllum (cph), and S. brachistotrichum (bst). These species are sexually isolated, thus their chromosome complement was doubled in order to successfully perform crosses with S. tuberosum haploids. Several tetraploid derivatives displayed good level of resistance to Phytophthora infestans. Interestingly, one of them derived from susceptible diploids. By contrast, three susceptible regenerants were yielded by resistant diploid clones. To study the genetic variability we were working with, AFLP analysis was performed on 20 tetraploids (11 from blb, 4 from cph, and 5 from bst), and on the diploid genotypes they derived from. Nine primer-enzyme combinations allowed the detection of polymorphisms of interest between species and within tetraploid genotypes within each species. Some AFLP bands present in diploid clones were not found in their regenerated tetraploid derivatives. By contrast, AFLP bands that were lacking in diploid genotypes were ex-novo detected in their derivatives. These events were probably due to somaclonal variation events due to the in vitro chromosome doubling. The genetic material evaluated was clustered based on the matrix of genetic similarities and a dendrogram was constructed to separated four distinct genetic groups. The implications due to this finding are discussed from a genetic and breeding standpoint.