Distribution of Xanthomonas oryzae pv. oryzae Pathotypes in Basmati-Rice-Growing Areas of Jammu and Kashmir, India

Rice is an important staple food for more than half of the world’s population. Though genetic potential commonly cultivated varieties rice diminished due to various biotic and abiotic constraints, bacterial leaf blight (BLB) caused by Xanthomonas oryzae pv. (Xoo) considered one its most destructive diseases in India. Based on morpho-cultural characteristics, pathogens isolated from leaves a plant showing typical BLB symptoms were identified as oryzae. Morphological studies revealed that pathogen Gram-negative, short rod, with rounded ends, single or pairs, light yellow, circular, whitish yellow straw-colored, convex, slightly raised, motile polar flagellum, capsulate non-spore-forming. Biochemical tests, viz., Gram reaction, KOH test catalyst test, showed positive reaction all isolates. Twenty isolates Xoo collected basmati-growing areas Jammu, Samba Kathua districts Jammu sub-tropics during 2019, their pathogenicity was confirmed five susceptible cultivars, Basmati-370, Pusa-1121, TN-1, SJR Jaya, leaf-clipping method, subsequently, Koch’s postulate established each case. Seven pathotypes, Pathotype 1, 2, 3, 4, 5, 6 7, total sample 20 2 dominant (100%), followed 5 (44.44%), 4 (40%), 7 (33.33%), 3 (22.22%) 1 (20%), sub-tropics. In district, highly distributed (44.44%) (33.33%) (22.22%). 40 percent distribution (20%). Only pathotype, i.e., recorded district 100 distribution. Five genes, Xa13, Xa4, Xa13 Xa5 + complete resistance, whereas Xa5, Xa7, Xa8, Xa21, Xa4 Xa21 response against It observed BLB-resistant genes moderately almost isolates, combinations resistance possessed high The diverse pathogenic variations existed population region Kashmir. exhibited differential lines, seven pathotypes (Pathotype 1–7) identified, virulence spectrum differentials occurrence 10, 20, 10 15 percent, respectively, To develop durable sustainable resistant it essential identify predominate race(s) specific geographical area continuously monitor pattern there.