Induced resistance in potato plants against verticillium wilt invoked by chitosan and Acibenzolar-S-methyl

Verticillium wilt of potato is a major limiting factor in potato production caused by Verticillium dahliae. The objective of this study was to evaluate the efficacy two elicitors including Acibenzolar-S-methyl (ASM) and Chitosan as plant activator in controlling of potato verticillium wilt in vitro and greenhouse conditions. ASM and chitosan were tested in vitro using Potato dextrose Agar (PDA) amended with five concentrations (0, 5, 50, 100, 500 μg a.i./ml). All the concentration of Chitosan reduced radial growth of V. dahliae in vitro significantly (p < 0.05) after 120 h (9 to 57.5%), Whereas, ASM did not significantly reduce on the growth of pathogen in vitro and reduced radial growth of pathogen very less (5.4 to 16.9%). The effective concentration of Chitosan that reduced the radial growth of V. dahliae to 50% (EC50) was 258.28 μg/ml. In greenhouse conditions, potato tubers c.v Agria dipped in aqueous solution of different concentration of elicitors and sown in soil of pots artificially infested with V. dahliae. Also, ASM and chitosan applied by foliar spray on potato seedlings at concentration 100 μg a.i./plant; 15, 25 and 40 days after sowing. Results shown all treatment significantly reduced disease severity and increased tubers fresh weights, but ASM was more effective than chitosan and reduced the potato verticillium wilt. The biggest disease reduction and increasing yields of potato belong to concentration of 500 μg a.i./ml of ASM by 67.8% and 56.7%, respectively. Results showed that ASM and chitosan may be inducing plant resistance and protected tubers of potato against Potato verticillium wilt. These chemical could provide a new approach for suppression of Potato verticillium wilt, but its practical use needs further investigation.