Systemic acquired resistance (Sar) study of phenolic acid amides against Meloidogyne graminicola infestation in rice

A pot study was undertaken to ascertain the Systemic Acquired Resistance (SAR) induced by three phenolic acid amides viz. N-hexyl-salicylamide, N-hexyl-2-hydroxycinnamamide and N-hexyl-4-hydroxycinnamamide in rice against Meloidogyne graminicola. The compounds were sprayed at five different concentrations viz. 500, 250, 125, 62.5 and 31.25 ppm. SAR study revealed that all the plant growth parameters (shoot length, shoot weight, root length and root weight) were positively influenced by the amides. The order of activity was N-hexyl-salicylamide > N-hexyl-2-hydroxycinnamamide > N-hexyl-4-hydroxycinnamamide > Salicylic Acid both at 7 and 14 DAI. As the nematicial activity increased, plant growth parameters also increased. All the compounds were found more effective at 500 ppm and showed better results than the commercially recommended salicylic acid. The biochemical study was also performed to check the Peroxidase (PO) and Phenylalanine Amonia Lyase (PAL) enzyme activities. It was found that both PO and PAL activities increased in all treatments over water control at 7 and 14 DAI for both shoot as well as roots. The activity was higher in shoots compared to root samples irrespective of the enzyme tested. The activity was highest in N-hexyl-salicylamide @ 500 ppm at 7 and 14 DAI. Among the compounds tested, N-hexyl-salicylamide was most effective @ 500 ppm with 64.29% reduction in gall formation.