Screening of tomato genotypes against early blight pathogen Alternaria solani using detached leaf assay method

Early blight (EB) caused by Alternaria solani is a destructive fungal disease of tomato (Solanum lycopersicum L.). Leaf blight, stem blight and apical fruit rot are the most prominent symptoms of the disease. It can cause complete loss of the crop when disease is severe. Thirty genotypes including wild relatives and hybrids of tomato were screened for early blight resistance under artificial inoculation by detached leaf assay method at ICAR-IIHR, Bengaluru. The genotypes screened under artificial conditions were grouped into six distinct categories based on percent disease index (PDI) recorded 7 days after inoculation (DAI) and disease was scored using 0–4 scale. Genotype LA-1777 was highly resistant. Six genotypes viz., NCEBR-1, NCEBR-4, Arka Alok, Arka Rakshak, Arka Saurabh and 8-3-3 were resistant. Seven genotypes were moderately resistant and rest of the genotypes were susceptible to early blight disease. The resistant genotype LA-1777 was very poor in its horticultural traits like size of the fruit and yield and it cannot be directly exploited, but it can be used in resistance breeding programme for developing superior cultivars and hybrids having resistance to early blight.