Nandita Jena
Abstract
The cell wall glucans were isolated from Phytopthora colocasiae that induce defense mechanism in Colocasia and the technique for in vitro screening of the Colocasia varieties for leaf blight resistance using the elicitor has been standardized. Colocasia, the important crop used as vegetable is affected by Phytophthora colocasiae which causes the leaf blight disease. Cell wall glucans were isolated from the mycelial cell walls of P. colocasiae. The elicitor was inoculated on the cut Colocasia leaves of ten local cultivars of Odisha to study the hypersensitive reaction. The hypersensitivity reaction in resistant cultivars was detected within 48-72 hours of incubation. The field tolerant cultivars Dhalasaru, Panisaru and Sankhasaru showed quick hypersensitive reaction by necrosis which was delayed or not expressed distinctly in the susceptible cultivars viz., Kalasaru, Satyabhama and Kujisaru cultivated in Orissa. Varietal screening for disease resistant in field condition of crop plants are time consuming and expensive. That also partially regulated by other biotic and abiotic factors and environmental conditions. But in-vitro screening is very fast, time saving, economic and free of other external factors. To monitor the response in resistant and susceptible hosts, elicitor injection and systemic induction in pot culture is easier than that under field condition. So the elicitor preparations will be useful for screening of Colocasia germplasm for resistance against leaf blight.