A doctoral dissertation at the Faculty of Agriculture on the impact of sitosterol and phenylalanine on the growth, yield, and secondary compound content of two okra cultivars under open-field and protected cultivation conditions.

The College of Agriculture at the University of Diyala discussed a doctoral dissertation entitled The Impact of Sitosterol and Phenylalanine on the Growth, Yield, and Secondary Compound Content of Two Okra Cultivars under Open-Field and Protected Cultivation Conditions. The study, presented by the student Ya’mar Ahmed Ali, aimed to elucidate the role of sitosterol and phenylalanine in enhancing plant growth and yield by stimulating increased production of certain biologically active compounds under both open-field and protected conditions for two okra cultivars. It also sought to identify the cultivar with the highest responsiveness in terms of growth, yield, and medicinally valuable secondary compound content.

The study reached several conclusions, among which were the following:

• The cultivar Abeer significantly outperformed the Batira cultivar in most vegetative, floral growth, yield attributes, and active compound content in okra plants.

• Foliar spraying with sitosterol and phenylalanine improved the vegetative and floral growth, yield, and active compound content of okra plants.

• Treatment with a foliar spray concentration of 150 mg L−1^{-1}−1 sitosterol led to improvements in most vegetative and floral growth traits, yield, and active compound content.

• Foliar spraying with a concentration of 100 mg L−1^{-1}−1 phenylalanine also enhanced these attributes.

The study recommends selecting the Abeer cultivar due to its superior vegetative and floral traits, yield, and active compound content. However, the Batira cultivar also demonstrated commendable vegetative and floral characteristics, yield, and active compounds. Additionally, it suggests experimenting with higher concentrations of sitosterol and phenylalanine than those used in the study to ascertain the maximum impact of these substances and determine the optimal levels to enhance vegetative and floral growth, yield, and active compound content without inhibiting growth.