Ghatak, AbhijeetKriti, Aakanksha2019-06-262019-06-262018-06http://krishikosh.egranth.ac.in/handle/1/5810110023A large number of fungicides for foliar disease management are developed with sulphur and copper compounds as the basic ingredient. These ingredients are known for environmental pollution with its degradation issue. With a very limited research results it is accepted that plant diseases can be managed by application of nanoparticle (NP) that could replace the mentioned ingredients from the agricultural system. The present investigation was undergone in order to explore the morphological and biochemical variation on nanoparticle application in two plant-pathosystems i.e. Bipolaris-sorokiniana-barley and Alternaria brassicicola-mustard. The laboratory synthesised NPs [25-32 nm for silver (Ag) and 29-37 nm for zinc (Zn)] at 100 ppm revealed almost 75-100% spore germination of B. sorokiniana and A. brassicicola was inhibited. Similarly, the same concentration found best to restrict mycelial growth of the two pathogens. NP-applied leaves produced smaller lesion size in comparison to the leaves devoid of NP application. Overall, lesion size was reduced by ~70% in barley and ~45% in mustard leaves when they received NP application 30 minutes before pathogen inoculation. However, in some genotypes this trend was not constantly evident. Similar result was observed for phenol estimation; the greater phenol was quantified in infected leaves where NP was applied before pathogen inoculation. In comparison to only pathogen inoculated leaves, higher level of phenol expression was seen in leaves treated with NP+P by ~19% and ~13% in barley and mustard, respectively. Higher amount of chlorophyll was harvested in leaves with NP application with or without pathogen infection in comparison to the infected leaves (no NP applied). This indicates the applied NP might catalyze a pathway for chlorophyll production. At the end, the effect of NP at field scale was determined. AgNP showed significantly lower disease severity of B. sorokiniana infection compared to ZnNP across genotypes. However, no definite trend was established for the two NPs in A. brassicicola infected mustard genotypes. The information generated in this work needs the further in-depth study in order to identify the mechanism of respective NP for reducing infection in the two plant pathosystems.ennullThesis