A field experiment materialized during the winter of 2022 at the College of Agriculture, University of Kerbala, to determine the effect of foliar spraying of several concentrations of NPK and amino acids on growth characteristics and yield of broccoli plants (Brassica oleracea var. Italica). The study implemented a randomized complete block design (RCBD) with two factorial experiments and three replications. The first factor included three concentrations of NPK (0, 1.5, and 2.5 g L^-1), and the second with three concentrations of amino acids (0, 1, and 2 ml L^-1). The findings demonstrated notable disparities, with the third concentration of NPK (2.5 g L^-1) exhibiting superior performance, giving a plant height of 63.78 cm, leaves per plant (18.076 leaves plant^-1), stem diameter (3.326 mm), flower disc weight per plant (510.84 g plant^-1), and the flower holder diameter (18.671 mm). Regarding the impact of amino acid, the concentration at 2 ml L-1 appeared with maximum values across traits, i.e., plant height (62.50 cm), number of leaves (17.477 leaf plant^-1), stem diameter (3.241 mm), flower disc weight (485.49 g), and the diameter of the flower container (15.972 mm). The interaction between the two factors displayed significant effects, with the highest interaction between the third concentration of NPK (2.5 g L^-1) and the concentration of amino acid (2 ml L^-1) arising in most traits.

Keywords: Broccoli (Brassica oleracea), NPK doses, amino acid, growth and yield traits

Key findings: In broccoli (Brassica oleracea), NPK at 2.5 g L^-1 provided better results than other doses for plant height, leaf count, stem diameter, floral disc weight, and flower stand diameter. Similarly, the highest averages for plant height, leaf count, stem diameter, floral disc weight, and flower stand diameter emerged with the amino acid at 2 ml L^-1.