Antioxidant potential of barley genotypes inoculated with five different pathotypes of f. sp. .

The stripe rust caused by the fungal pathogen, f. sp. in barley ( L.) is a global problem that threatens the production of barley. The present study examined the disease reaction, free radical scavenging potential, non-enzymatic antioxidants like total phenols, o-dihydroxy phenols, flavonoids along with total chlorophyll, chlorophyll a, chlorophyll b and total carotenoids of the four barley genotypes viz. Jyoti (susceptible), RD2900, RD2901 and RD2552 (resistant) infected with five different pathotypes (M, G, 57, Q and 24) of f. sp. The disease reaction showing RD2901 in the category of immune to very resistant genotype followed by RD2552 in immune to resistant and RD2900 as moderately resistant and Jyoti as susceptible, which was well correlated with biochemical studies. RD2901 possessed higher antioxidant potential in terms of 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity, ferric reducing antioxidant power, reducing power and nitric oxide scavenging activity under control conditions and were maintained sufficiently high on inoculation with different pathotypes (M, G, 57, Q and 24) of f. sp. . Further, these free radical scavenging activities showed the positive correlation with total phenols, o-dihydroxy phenols, flavonoids which in turn might be contributing in tolerance behaviour of this genotype. However, Jyoti with sensitive behaviour towards M, G, and 24 pathotypes depicted minimum DPPH activity and reducing power under control conditions.