Induction of defense proteins and status of late blight of potato incidence in response to jasmonic acid application in potato

Abstract

In the present work, effect of foliar and tuber treatment by JA @ 0.5 and 1.0 mM, on leaf defence enzymes in relation to Late Blight incidence in, KufriJyoti (Tolerant) and KufriPukraj  (Highly susceptible), was studied. Tuber treatment (in solution) was given for 10 minutes before sowing. Foliar application was done at 24and 34 days after planting (DAP). Leaves were collected for seven consecutive days after 24and 34 DAP in both treatments. Sporangial solution (10⁴spores/ml) was sprayed after 2^nd sample collection. Disease incidence (%) and severity (%) was recorded at 7, 14 and 21 day post infection. JA @ 0.5mM caused statistically significant (at 5% level) increase in chitinase, glucanase, peroxidase, catalase, polyphenol oxidase, phenylalanineammonialyase, total sugars and total soluble proteins   in KhufriJyoti. Among the enzymes chitinase and PAL showed maximum increase (2.3, 1.6 fold respectively) in activity at 0.5mM JA foliar spray. Least disease incidence and severity was recorded in tolerant potato cultivar.The second foliar spray acted as a booster dose in terms of higher fold increase in activities of defense enzymes. The biochemical parameters registered significant negative correlation with disease severity. Foliar route was more efficacious. Both varieties responded to JA treatment. Integration of disease tolerance and JA application proved effective  againstlate blight of potato