Resistance of some tomato genotypes to early blight (Alternaria solani)

Early blight is one of the most destructive fungal diseases of tomato caused by Alternaria solani. Under favorable conditions it could cause high yield losses. Resistant cultivars are the most convenient way for disease control. The aim of this paper was to screen the resistance of 20 tomato genotypes (collection of the Institute of Field and Vegetable Crops) against natural infection of early blight. A trial was conducted at experimental field of Vegetable Crops Department in Rimski Sargevi, (Vojvodina, Serbia) during 2011. The tomato genotypes originate from nine countries. The intensity of early blight was assessed according to scale 1-9. After the fruit assessment the fruit weight and fruit dry matter content were measured. Obtained data were analyzed by ANOVA, Kruskal-Wallis test and Spearman correlation coefficient by statistical software Statistica ver. 12 (StatSoft, Inc., USA). The medians of intensity of leaf infection were ranged from 1 to 3. There were significant differences among genotypes. Genotypes Wilma, Red cloud and Dwarf stone nano had significant lower disease intensity than Red ball, UC- 134-1-2 VF, Gevgelijski, V1, V3, V7, V8 and V19. Lower disease intensity was also observed in genotypes Wican and Rutgers comparing to Red Ball and V19. There were no significant differences in level of the fruit infection. Dry matter content ranged from 4% (Express) to 6.1% (Ponderosa red). The highest fruit weight had genotype Wilma (215 g) and the lowest genotype Express (70 g). Intensity of leaf disease was in the negative correlation with fruit weight and in the positive correlation with dry matter content.