Seed-borne nature and transmission of Pseudomonas syringae pv. pisi in pea

Pea (Pisum sativum L.) is an important vegetable pulse crop. The bacterial blight caused by Pseudomonas syringae pv. pisi is a threat for the cultivation of pea in Rajasthan. The survey was conducted in pea growing districts during year 2010 and 2011. The dry seed examination of 127 seed samples collected from 25 districts revealed asymptomatic (47.25–89.5%), moderately discoloured (6.25–41.75%) and shrivelled discoloured (3–16%) seeds. Based on standard cultural, biochemical and pathogenicity tests, the pathogen was confirmed as Pseudomonas syringae pv. pisi. Off 127 seed samples collected 125 seed samples yielded the bacterial pathogen with varying incidence (2.25–85.5%) and transmission of pathogen ranged from 336% in 45 days. The seed-borne inoculums caused pre and post emergence losses and symptoms of water soaked translucent brown lesions, splitting of plumule, radical and necrotic spots with bacterial oozing on cotyledonary leaves.