Abstract

Bacterial blight (BB) cf rice caused by Xanthomonas campes ris pv. oryzae (Dye et. al., 1980) produces leaf blight and kresek. Blight form is more serious in rice growing districts of Madhya Pradesh (M. P.). Weather conditions viz., average monthly, maximum temperature (31°c); minimum temperature (22°c) and relative humidity (92%) favour BB during the panicle initiation stage of the crop. Pathogenic variability of the organism from country to country and from location to location within a country has been fully recognised (Buddenhagen and Reddy, 1972 and Mew et. al., 1982). Earlier Mohiuddin and Kauffman (1975) classified the Indian isolates in to eight groups, but later studies at All India Co-ordinated Rice Impro- vement Project, Hyderabad (1979) (presently Directorate of Rice Research) suggested only two pathotypes. Later studies at Punjab, Haryana. North West India and Tamilnadu indicated the prevalence of pathotype 1 only (Reddy, 1980. Mariappan et al., 1981, Durgapal, 1985 and Ahuja et. al., 1986). Pathotypes of M. P. have been studied for the first time through this note.

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