Effect of spraying with benzyl adenine, salicylic acid and phenylalanine on the yield of volatile oil of fennel plant (Foeniculum vulgare Mill) and its content of some secondary compounds

The field experiment for the current study was conducted at Experiment Station (A) of the Department of Field Crops-College of Agricultural Engineering Sciences -the University of Baghdad for the period from November 2018 to June 2019 in order to know the response to stimulating the production of volatile oil and secondary metabolism compounds of the Fennel plant using different concentrations Of the growth regulators [Benzyl adenine (BA), Salicylic acid (SA) and Phenylalanine (Phe)]. The Randomized Complete Block Design (RCBD) was applied according to the order of factorial experiments with three replications. Growth regulators were used with the following concentrations : (0, 2.5, and 5.0 mg L-1 of BA, symbolized by BA0, 2.5BA, and 5BA, respectively, and 0, 150 and 300 mg L-1 of SA and Phe, symbolized by 0SA, 150SA, and 300SA). and 0 Phe, 150 Phe and 300 Phe respectively), the results of the current study showed the excelled and the different study factors with their bi and triple interactions in giving the highest averages of volatile oil content and production of secondary metabolites, The highest values were recorded in this study when spraying with growth regulator BA as well as their interactions with the rest of the factors. The spray treatment with a concentration of 2.5 mg L-1 achieved the highest average oil content of 25.73 ml. kg-1 with an increase of 45.2% compared to the control treatment, as well as It gave the highest values for the concentration of (t-Anethole, Fenchone, Limonene, and α-pinene) compounds, which were 1.231, 0.554, 0.866 and 0.857 μg ml-1 for the compounds, respectively, with an increase of 41.82, 26.48, 120.92 and 98.38%, respectively. It can be concluded from this study that the growth regulators used have a clear effect in stimulating the production of volatile oil and secondary metabolic compounds in the sweet bean plant.