Effects of three essential oils on the phytohormones production against Magnaporthe oryzae B.C. Couch, A rice blast pathogen

This study aimed to evaluate the effect of three essential oil formulations on the defence mechanism of rice plants against Magnaporthe oryzae, a rice blast pathogen in Burkina Faso. The experimental set-up was a randomised block of five treatments, including T0, T1, T2, T3 and T4. Rice plants were inoculated with M. oryzae on the 14th day after transplanting and essential oils were applied one week after inoculation. The biomass of the rice plants was collected at the full tillering (FT) and paniclar initiation (PI) stages and then sent to the laboratory. The parameters assessed were the levels of signalling and defence molecules. The results showed that for signalling molecules, high ethylene levels were recorded by treatments T2 in FT (6.61 mg EA/g) and T4 in PI (5.59 mg EA/g). The highest salicylic acid contents were obtained by treatment T1 with 106.42 mg/100 g in FT and 96.98mg/100 g in PI. In terms of defensive phytocompound content, treatment T4 recorded the highest levels of polyphenols (256.33 mg EA/100 g) and flavonoids (74.58 mg EA/100 g) in FT. The highest alkaloid and chlorophyll contents were recorded in treatment T2. These were 33.9 mg EA/g in FT and 26.35 mg EA/g in PI for alkaloids, 1.54 g/100 g in FT and 1.78 g/100 g in PI for chlorophyll a and 1.73 g/100 g in FT and 1.77 g/100 g in PI for chlorophyll b. These results are importants because they will enable to control M. oryzae in rice fields. published by the  International Journal of Agronomy and Agricultural Research | IJAAR