Screening of Crossandra (Crossandra infundibuliformis (L.) (Nees.) Genotypes for Root Lesion Nematode

An experiment was conducted with ten crossandra genotypes collected from various institutions and local sources at Department of Floriculture and Landscape Architecture, Horticultural College and Research Institute, Coimbatore. The experiment was laid out using FCRD design with three replications with genotypes uninoculated and inoculated with nematodes.  Observations were taken after 60 days of inoculation. The results revealed that Nilakottai local and Arka Shravya recorded the least percentage of reduction of shoot weight (13.73 & 14.55%) and root weight (18.83 & 16.93%) under inoculated condition. The increased percentage of phenol, polyphenol oxidase, peroxidase activity and phenylalanine ammonia lyase was higher in Nilakottai local and Arka Shravya and the least was noticed in Dharmapuri local under inoculated conditions. The root necrosis percentage ranged from 7.05 to 21.17. The lowest root lesion percentage was recorded in genotype Nilakottai local (7.05) followed by Arka Shravya (8.67) and the highest necrosis percentage was observed in genotype Dharmapuri local (21.17). Resistant reaction was noticed in genotype Nilakottai local and Arka Shravya. Tolerant reaction was observed in genotype Delhi crossandra, Arka Ambara, Arka Chenna, Arka Shreeya and Arka Kanaka. The susceptible reaction was found in genotype Villupuram local, Neyveli local and Dharmapuri local.