Differential sensitivity of callus derived from immature panicles of rice cultivars to the non-specific toxin of Pyricularia grisea

An in vitro screening procedure was adapted to study the sensitivity of callus to the toxin picolinic acid of Pyricularia grisea in four rice cultivars. The lethal dose LD₅₀ was determined on the basis of probit-log dosage response curve. The values of LD₅₀ were 10, 51, 129 and 151 ppm for Tetep, Newbonnet, Labelle and M 201, respectively. The callus culture of cultivar Tetep, with a known broad spectrum of resistance, exhibited a high toxin sensitivity whereas the highly susceptible cultivar M 201 showed low sensitivity indicating the absence of relation between host plant specific resistance to blast and resistance of the callus to toxin. This revised version was published online in June 2006 with corrections to the Cover Date.