A Procedure of Drip Inoculation for the Evaluating Lettuce Cultivars for Resistance to Root Rot

Abstract

A procedure of drip inoculation to lettuce seedlings grown in a plug tray was studied for evaluating cultivars resistant to root rot (Fusarium oxysporum f. sp. lactucae). Seedlings 1 week old were the most susceptible. Clear symptom expression was obtained with inoculum suspension of 2 ml per plug tray cell at a concentration of 5 × 10₆ bud cells/ml of the pathogen. Watering from the plug tray bottom had no negative effect on the expression of cultivar resistance. Our procedure proved effective for the screening root rot resistance.