The presented experiment on faba bean (Vicia faba L.) began in the winter of 2022–2023 at the College of Agriculture, University of Anbar, Anbar, Iraq. The study aimed to determine the effects of foliar application of zinc on the growth and physiological traits of the faba bean genotypes. The experiment had a randomized complete block design (RCBD) with a split-plot arrangement and three replications. The prime plots included three concentrations of zinc, i.e., 0, 30, and 60 mg Zn L^-1, while the subplots comprised three different genotypes (American, Dutch, and Spanish) of faba beans. The results revealed that the faba genotypes significantly displayed their latent potential in growth and physiological parameters. The American faba bean genotype proved superior in plant height (37.52 cm), leaf area (1413 cm² plant^-1), and zinc concentration in leaves (113.30 mg kg^-1 dry matter). However, the Spanish faba bean genotype led to an average leaf chlorophyll content (56.59 SPAD). The zinc foliar application with the highest concentration (60 mg L^-1) provided the least number of days to flowering (60.89 days) and also excelled in obtaining the tallest plants (41.13 cm), branches per plant (3.85), leaf area (1337.6 cm² plant^-1), the chlorophyll content (52.23 SPAD), and the zinc concentration in leaves (116.58 mg kg^-1 dry matter). The interaction of the American faba bean genotype and the highest zinc foliar application (60 mg L^-1) significantly affected the plant height, leaf area, and zinc concentration in leaves. The interaction between the Spanish genotype and zinc concentration (60 mg L^-1) gave the highest average for leaf chlorophyll content, and the interaction of the Dutch genotype with the highest zinc concentration exhibited a shorter period from planting to flowering.

Keywords: Vicia faba L., exotic genotypes, vegetative growth traits, micro-nutrients

Key findings: Zinc foliar application significantly impacted faba bean genotypes for growth and physiological traits. The superiority of the high concentration of zinc (60 mg L^-1) in maturation and physiological features might be due to its positive role in stimulating various physiological processes and improving plant performance. In addition to delaying the leaf senescence by preserving the chlorophyll content, it positively affected the increase in photosynthesis process efficiency.