Impact of Cutting the Growing Apex and Nitrogen Fertilizer on the Growth and Yield of Brussels Sprout (Brassica olelecea var. gemmifera)

Background: In Brussels sprouts, the number of buds along the stem can be increased by cutting the growing apex process, which stimulates the formation of lateral buds and increases plant yield and total yield. Methods: An experiment was conducted in the Horticulture and Landscape Department/College of Agriculture and Forestry/ University of Mosul/Iraq during the 2020-2021 season to investigate the impact of cutting vis a vis no cutting of the growing apex and adding nitrogen fertilizer (urea 46% N), with four levels (0, 50, 75 and 100) kg N. Ha-1 on growth and yield of Brussels sprout. The study was conducted in a factorial experiment in RCBD design, with three replicates. Result: The results showed that the treatment of cutting the growing apex increased the total weight of heads per plant, head length, dry matter percentage and protein percentage. While the treatment without cutting the growing apex increased plant length, leaf number and leaf area of plant. Also, the nitrogen fertilizer gave a significant increase for all parameters compared to the control (0 nitrogen) and the highest values were from adding 100 Kg. N. Ha-1, which reached 87.917 SPAD for Chlorophyll, 3624.3 cm2 for plant leaf area, 482.37 g. for total weight of head per plant, 195.33 for number of heads per plant,3.65% for nitrogen and 22.812% for protein in head. The interaction treatments between cutting the growing apex and nitrogen fertilizer gave a significant difference for many parameters.