The level of resistance to late blight Phytophthora infestans (Mont.) de Bary in tomato breeding genotypes in Serbia

Abstract

Late blight (Phytophthora infestans (Mont.) de Bary) was identified as one of the major diseases causing significant economic losses in tomato production. Thus, the development of resistant cultivars and hybrids was included in tomato breeding programs at the Institute for Vegetable Crops, Smederevska Palanka. A line (S-31), Tomato late blight resistance gene Ph-2 carrier, was diallely crossed with four susceptible lines possessing good production characteristics (S-49, S-31, hom-3 and hom-4) in order to obtain resistant high-yield and quality hybrids. Parental lines and five F1 hybrids, as well as three commercially grown susceptible cultivars (Narvik SPF, Adonis, SP-109, negative control) were tested for resistance toward this pathogen.Sensitivity was evaluated ten days after inoculation on the basis of leaf area necrotic spot, using I to VI level scale. The results imply dominant or partially dominant inheritance pattern. Three commercially grown cultivars were susceptible, as expected. Five of F1 hybrids including S-31 and hom-3 parents were resistant to late blight. The best hybrids were S-31 x hom-3 and S-31 x hom-4 when the morphological traits, yield and resistance were taken into account. Obviously, lines from group hom contributed to increased resistance to tomato late blight with respect to resistant parent. Key words: Inheritance, Ph-2, resistance gene, Solanum lycopersicum.