Ontogenic Predisposition of Tomato Foliage to Early Blight Caused by Alternaria solani under Mountainous Conditions of Kashmir

This study explores the susceptibility of tomato plants to early blight caused by Alternaria solani concerning their chronological and physiological ages. While previous research has noted higher resistance in younger potato plants and an acropetal increase in resistance within plant leaves, such investigations are limited in tomatoes. Our study aimed to address this gap by investigating the influence of chronological and physiological ages on early blight resistance in tomato plants. Using the Keck Ruth Ageti cultivar, we conducted experiments at various plant growth stages. Chronological age variations were achieved by sowing seeds at 10-day intervals, with inoculation occurring when the youngest seedlings reached 20 days. Leaf sampling from different sections facilitated the evaluation of physiological age effects. Results showed a direct relationship between plant age and disease susceptibility, with older plants exhibiting higher incidence rates. Moreover, resistance increased from lower to upper leaves, with top leaves demonstrating the highest resistance.