Response of some black seed (Nigella sativa L.) varieties to foliar application by zinc on growth, yield and seed quality planting in two locations

Black seed (Nigella sativa L.) is an internationally important oil crop, field experiment was carried out at two locations in Erbil province, Kurdistan region-Iraq, at Grdarasha Research Field, Collage of Agricultural Engineering Sciences, is locating at 36. 40ᵒ N, 44.10ᵒ E and at an elevation 470m above sea level and at Khabat Technical Institute, and Khabat field is locating at 36. 27ᵒ N, 43.65ᵒ E and at an elevation 250m above sea level, during growing season of 2024-2025 to investigate the impact of spraying of different Zinc concentration were arranged with 4 levels (0, 100, 200 and 300ppm) on growth and yield component, fixed oil and protein seed content traits of three black seed varieties (Russian, Syrian and Local). The result of the study revealed that in both locations, the greater rates of most of growth parameters were found with Syrian and locally varieties at 300ppm. Yield contributing characters like No. of capsules plant-1, No. of seeds capsule-1, 1000 seed weight and seed yield, findings show that in grdarasha field Russian and local varieties occupy first position, but in khabat field Syrian was surpassed. In both locations the maximum production of yield parameters was obtained with zinc foliar application at 200 and 300ppm. For interaction, Syrian and local varieties with all Zinc spray was recorded the highest values. Fixed oil content (31.43%) recorded the maximum amount in Syrian variety and protein (22.66%) in local variety in Grdarsha field, while in khabat field Russian variety increased the oil to (30.21%) and protein for local to (24.33%), in both locations oil and protein content and their yield, 200 and 300 ppm selected the greater data. For interaction between treatments, all varieties had significant positive with all zinc spray. T-test analysis was used to compare between the field locations, results show on No. of branches and oil content had significant differences between the two fields.