Response of Fennel (Foeniculum vulgare, Mill) plants to foliar application of moringa leaf extract and benzyladenine (BA)

Abstract

The aim of this study was to investigate the influence of foliar application of Moringa oleifera leaf extracts (control, 2.5% and 5% aqueous MLE, 2.5% and 5% ethanolic MLE) and/or benzyladenine (control, 50, 100 and 200 ppm BA) on the growth, fruit and oil yield and its main components and chemical constituents of fennel (Foeniculum vulgare, Mill.) plants. The obtained results revealed that treated fennel plants with MLE and/or BA resulted in a significant increase in the vegetative growth, number of umbels/plant, fruit and oil yield per plant and feddan as well as total carbohydrates in fruits, chlorophyll a, b and carotenoids, nitrogen, phosphorus and potassium contents in leaves compared to untreated plants. Generally, the application of moringa leaf extracts was more effective than BA treatments. The individual treatment of aqueous MLE at 5% or BA at 100 ppm gave the best results of the previous mentioned characteristics followed by 5% ethanolic MLE or 50 ppm BA compared to the control and the rest of tested individual ones. The highest values of all studied parameters were obtained by using 5% aqueous or ethanolic MLE combined with 100 ppm BA. The increments were 91.1% and 85.3% in fruit yield/feddan, 52.5% and 46.3% in volatile oil percentage and 192.4% and 172.0% in oil yield/feddan, respectively over the control. The G.C. analysis of the volatile oil showed that the major component of volatile oil was methyl chavicol (estragole) with concentration range from 77.5% to 87.3%. The minor compounds were myrcene and limonene. The best treatment for decreasing the concentration of methyl chavicol (77.5%), which is undesirable component in fennel oil resulted from the combination of 5% aqueous MLE plus 100 ppm BA. Therefore, it could be recommended that spraying fennel plants with 5% aqueous MLE plus 100 ppm BA for obtaining higher vegetative growth, fruit and oil yield.