Isozyme and amplified fragment length polymorphisms from Cephalosporium maydis in Egypt

Isoenzyme and amplified fragment length polymorphisms (AFLP) variation with in a set of 48 isolates of Cephalosporium maydis was characterized. These i solates included ten cultures that have served as standards in the Egyptian maize resistance breeding program and 38 additional strains collected from Il governates in Egypt during the 1997 growing season. Eight isozymes also were tested, but only five (acid phosphatase, fumerase, glucose-4-phosphat e isomerase, isocitrate dehydrogenase, and malate dehydrogenase) produced i dentifiable bands and all five of these enzymes were monomorphic. Sixty-eig ht AFLP primer-pair combinations were used and 865 bands were scored, of wh ich 288 (33%) were polymorphic and could be used to discriminate four disti nct subgroups, or lineages. Representatives from only two of the four linea ges are included in the set of ten strains that has been used to challenge new lines in the Egyptian maize breeding program. From among these 68 prime r-pair combinations, we identified a set of four AFLP primer-pairs that wer e strongly correlated (Pearson's r > 0.85) with the full data set that can be used as markers to determine the distribution of these lineages and to i dentify new lineages in field populations.