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

Giardini Naxos, Italy - 18/21 September, 2002

ISBN 88-900622-3-1

Poster Abstract - 4.49

IDENTIFICATION OF RAPD AND CAPS MOLECULAR MARKERS LINKED TO FUSARIUM OXYSPORUM F. SP. MELONIS RESISTANCE GENES IN MELON GENOTYPES

SESTILI S., CAMPANELLI G., FICCADENTI N.

Research Institute for Vegetable Crops, Section of Ascoli Piceno, Via Salaria 1, 63030 Monsampolo del Tronto (AP), Italy

nadiaf@insinet.it, tel: +39735701706, fax: +39735703684

Cucumis melo, Fusarium oxysporum f. sp. melonis, CAPS, RAPDs

Fusarium wilt, caused by Fusarium oxysporum Schlecht f. sp. melonis Snyder & Hans, is a severe disease worldwide of melon (Cucumis melo L.). It occurs throughout Italy, Europe, North and Central America, Asia and Africa. Four races of this fungus were identified: 0, 1, 2 and 1,2. Resistance to Fusarium oxysporum f. sp. melonis races 0 and 1 and races 0 and 2, is controlled by two independent genes Fom-2 and Fom-1, respectively. No genes have been found that confer high levels of resistance to race 1,2. Control of Fusarium wilt relies primarily on resistant cultivars. To facilitate the breeding process, genetic markers associated with resistance genes to Fusarium wilt, could be used to screen large number of individual plants to ascertain introgression of resistance. Five doubled-haploid melon lines, parthenogenetically originated using irradiated pollen, three cvs of C. melo var Cantalupensis (Vedrantais, Charentais T and Isabelle), Line 7-82 of var. reticulatus and the Italian landrace Giallo di Paceco of var. inodorus were used to study the linkage between molecular markers and the resistance and susceptibility against the Fusarium oxysporum f. sp. melonis. The RAPD-PCR analysis was performed by using 50 different primers, three RAPD markers (UBC #596, E07 and G17) linked to the Fom-2 resistant gene and four SCAR primers derived from E07 and G17 RAPD primers. Out of 50 primers used, two (B12, B15) were able to amplify polymorphic fragments in all the genotypes tested. As previously reported by other authors, the derived SCAR primers EO7SCAR-1/E07SCAR-2 and G17SCAR-1/G17SCAR-2 yielded a single 1.25-Kb fragment and a 1.05-Kb fragment respectively, from both resistant and susceptible melon lines under study, thus confirming locus-specific associated primers. Ideal CAPS-markers associated to susceptible and resistant melon genotypes were yielded by three restriction endonucleases (MspI, BclI and BssSI). This strategy could be used as a starting point to identify genetic markers linked to genes for resistance to races 2 and 1,2 of Fusarium oxysporum f. sp. melonis.