Evaluation of the Effect of Variable Fertilization Formulas on the Severity of Viral Diseases of Five Tomato Cultivars in Southern Togo Using a Linear Model

One of the solution approaches to tomato viral diseases is undoubtedly the cultivation of tolerant cultivars. However, the environment in which these tomatoes are grown must allow them to favorably express their resistance to viruses. The soil nutrients brought or not are part of this environment. The objective of this study is to find ways and means from fertilization to create favorable conditions for the resistance of tomato cultivars to viruses. To do this, two experiments were conducted at the agronomic experiment station of the University of Lomé during the long rainy seasons of 2019 and 2020 under five tomato cultivars (Caraïbo, Mongal-F1, Petomech, Tropimech and Adakamenou) under the conditions of five fertilization formulas, T0 (0 fertilizer), T1 (200 kg NPK 15 15 15 and 100 kg urea 46% ha-1), T2 (10 t cattle manure ha-1), T3 [ (T1+T2)/2] and T4 (300 kg NPK 15 15 15, 67 kg urea 46% ha-1 and 5 t ha-1 of cattle manure). The split-plot design was used where the fertilizers were in main plots and the cultivars in sub-plots. The linear regression of virus severities observed during the experiment according to a rating scale from 1 to 5 made it possible to describe the behavior of the cultivars. The regression's lines slopes varied from 10.55% to 43.72% under the unfertilized plants; from 2.92% to 12.4% under fertilized Caraïbo plants; from 6.70% to 9.80% under fertilized Mongal-F1 plants; from 26.77% to 49.46% under fertilized Petomech plants; from 48.77% to 63.55% under fertilized Tropimech plants and from 5.22% to 16.76% under fertilized Adakamenou plants. It follows that the behavior of a tomato cultivar with respect to viruses differs according to the fertilization formula that has been given to it and that taking fertilization into account would be essential in the management plans for tomato viruses.