Two field experiments were conducted during two successive seasons to study the effect of foliar application with Phenylalanine (zero, 50 and 100 ppm) and /or nickel (zero, 50 and 100 ppm) on growth, yield and essential oil components of genoveser basil plant (Ocimum basilicum L. var. Genoveser). Application of the combined treatment (100 ppm Phenylalanine + 50 ppm nickel) resulted in the maximum values of all growth parameters, oil content and estimated yield of herb, leaves and oil. The essential oil was analyzed using a gas liquid chromatography-mass spectrometer (GC-Ms). All treatments proved that linalool was the main compound followed by 1,8 cineol, α-bergamotene, Ʈ cadinol and α-cadinol respectively. These compounds representing about 78.64% of the total oil constituents of genoveser basil. Application of 100 ppm Phenylalanine + 50 ppm nickel increased the relative percent of linalool, α-bergamotene, Ʈ cadinol α-cadinol except 1,8 cineole which was decreased by this treatment. Key words: Genoveser basil, phenylalanine, nickel, yield, essential oil constituents.

Coriander is one of the most popular and intensely used spices owing to its multipurpose uses worldwide. It is mainly cultivated for the production of its dried seed and fresh leaves. The present study aimed to evaluate the application of compost and foliar spraying of TiO₂ on the yield and essential oil composition of coriander. Two field experiments were conducted during two successive seasons; after that, the yield parameters were determined, and the essential oil of the seeds was extracted and analyzed via gas chromatography-mass spectrometry (GC-MS). Results indicated that coriander growths at both years were significantly affected by compost application and foliar application of TiO₂, and a significant interaction of these two factors also occurred. Compost application at 50 m³ caused significant increments of 55% and 46% in umbels number and 75% and 64% in seed yield in the first and second season, respectively, compared with control. The application of compost to the coriander plant significantly influenced oil percentage and oil yield per ha. The maximum oil percent was recorded in control plants. Foliar application of TiO₂ resulted in significant improvement in plant height, number of umbels, and seed yield of coriander as compared with control and reached their maximum values at 6 g L⁻¹ compared with the control; foliar application of TiO₂ at 2 g L⁻¹ enhanced numbers of umbels by 22% with no significant differences between 2, 4, and 6 g L⁻¹ treatments in the first season and by 24, 33, and 48% in the second season. Increases in seed yield accounted for 34, 43, and 64% in the first season and 21, 36, and 45% in the second season due to titanium dioxide application of 2, 4, and 6 g L⁻¹, respectively. The maximum content of linalool (87.61%) and minimum content of estragole (0.7%) was recorded at 4 g L⁻¹ titanium dioxide with no compost.

| Calendula is mainly grown as a single purpose plant for its flowers or recently for its seeds, whereas information for calendula cultivation for both flowers or petals and seed production is very scarce. A field study was conducted on two seasons to evaluate the effect of petal harvesting on flower heads fresh and dry weights, monthly and cumulative number of flower heads/plant, seed yield, fixed oil percentage and fatty acid analysis of pot marigold (Calendula officinalis). A Randomized Complete Block Design (RCBD) was used to arrange the treatments in three replicates, (H): petal harvesting and (C): without petal harvesting (control). Petal harvested plants produced a significantly much more harvestable total flower yield of 297-350 per plant than control with 48-51 flower/plant. Further, petal harvesting has significant effect on the flowers number and it increased 6-7 folds; hence possibly improve the compensation ability of plants to set new buds. Petal harvesting had positive significant effects on plant fresh and dry weights, seed yield but adversely affected flower fresh and dry weights as well as seed oil percent (%). Seed oil percent ranged from 11.76 to 11.94 in petal harvesting treatment compared to control that ranged between 14.01 to 14.38. Petal harvesting resulted in a significant reduction in oil percent by 19 % and 20% when compared to no petal harvesting in the first and second season, respectively. The major constituents of the extracted oil from calendula seeds were calendic acid (45.95-46.27%) and linoleic acid (26.56-26.81%) whereas palmitic acid (5.23-5.32 %) oleic acid (5.87-6.72 %), stearic acid (3.34-3.41%), avenoleic acid (2.15-2.46%) and sterculic acid (3.27-3.89%) were the predominant constituents. It can be said from our results that it is possible to perform eighteen petal harvests to be used for pharmaceutical or coloring and dying purposes and at the same time keep the flowers on the plant and get the highest seed yield for industrial applications.

Two consecutive field trials (2019 and 2020) were conducted to investigate the effect of foliar spraying of algae and royal jelly extracts on growth, essential oil content and composition of lemon verbena (Aloysia Citriodora) plant. Three concentrations of algae extract (0, 0.5 and 1 cm³L⁻¹) and three concentrations of royal jelly (0, 1 and 2 gL⁻¹) were used. All algae and royal jelly treatments positively impacted growth characters of lemon verbena (Aloysia Citriodora) plant viz, plant height, fresh and dry weights of herb and essential oil contents in both harvests during the two seasons. Plants sprayed with 0.5 cm³L⁻¹ algae and 1 gL⁻¹ royal jelly extracts produced the highest herb fresh and dry weights and essential oil contents. D-Limonene percent in the essential oil varied from 21.4 to the maximum of 25.9 % when plants were sprayed with 1 cm³L⁻¹ of algae + 1 gL⁻¹ of RJ. Geranial and neral maximally enhanced by 1 gL⁻¹ without algae spraying which recorded 12.5 and 9.8 % respectively.