Seed-borne nature of peronospora-parasitica in raphanus sativus

The alkali maceration technique was used to detect the seedborne nature ofPeronospora parasitica inRaphanus sativus. Four cultivars ‘Japanese white’, ‘Arka nishant’ ‘Pusa desi’ and ‘Pusa reshmi’ were used to confirm the presence of pathogen in the seed. The percentage of embryonal infection in the cultivars were 12·5, 0·5, 0·25 and 0·1 respectively. The percentage of seedling infection is directly correlated to the percentage of embryo infection. The possibility of using this technique in quarantine screening is discussed