Marchitez Vascular del Tomate: I. Presencia de Razas de Fusarium oxysporum f. sp. lycopersici (Sacc.) Snyder y Hansen en Culiacán, Sinaloa, México

the objective of this study was to determine the genetic variability of fusarium oxysporum f. sp. lycopersici (fol) in culiacan, sinaloa, mexico, a national important tomato-producing region, and to search for resistantce in species of lycopersicon, landraces, improved but obsolete varieties of different origin present in the state. one hundred samples of tomato plants showing symptoms of fusarium wilt disease were collected in culiacan, from which the fungus was isolated, and through inoculation of differentials bonny best, manapal, walter, and i3r3, races 1, 2, and 3 were identified. all the genotypes evaluated were susceptible to race 1, sixteen resistant to race 2, and only four resistant to race 3. twenty nine isolates of fol were isolated and identified to the race level; 24 % belonged to race 1, 14 % to race 2, and 62% to race 3. resistant materials to race 2 were lycopersicon esculentum cv. saladette la.2662 (88l1368); l. esculentum cv. primitive la.147 (90l3518); and l. chmielewskii la.2663 (85l8673-8676); and to race 3, l.pimpinellifolium la.722 (86l9486); l. pimpinellifolium la.2184 (87l0413); l.peruvianum la. 462 (79l4445-4449), and l. esculentum cv. motelle la.2823 (87l0382).