Document Type : Research Paper

Authors

• Mostafa Alinaghizadeh ¹
• Mohammad Azimi Gandomani ²

¹ Assistant Professor of Agriculture Department, Faculty of Technical and Engineering, Payame Noor University, P. O. Box 19395-4697, Tehran, Iran.

² Faculty of Technical and Engineering, Payame Noor University, P. O. Box 19395-4697, Tehran, Iran.

Abstract

    Background and Objectives: Medicinal plant Plantago ovata is effective in treating gastrointestinal disorders and improving intestinal function due to its bioactive compounds, such as mucilage. Given the importance of psyllium as a valuable medicinal plant and the water resource limitations in many regions, this study aimed to investigate the effect of sowing date on the growth and yield characteristics of psyllium under different irrigation regimes in the climatic conditions of Rafsanjan, Iran.
Methodology: This experiment was conducted during the 2022–2023 growing season in Rafsanjan, Iran, at a farm located at 30°24′N latitude, 55°59′E longitude, with an elevation of 1467 meters above sea level. The area has an annual average rainfall of 120 mm and maximum and minimum temperatures of 43°C and -5°C, respectively. The experiment was laid out in a strip-plot design based on a randomized complete block design (RCBD) with three replications. Irrigation treatments, applied in the horizontal strips, included four levels: 40%, 60%, 80%, and 100% of the crop water requirement. Sowing dates (March 10, 2023, March 25, 2023, April 10, 2023, and April 25, 2023) were assigned to vertical strips. Irrigation treatments were initiated after complete seedling establishment (3–4 leaf stage) and continued until physiological maturity. The irrigation water requirement was calculated using AGWAT software, with water volumes of 1430, 1144, 858, and 572 cubic meters per irrigation for 100%, 80%, 60%, and 40% water requirement levels, respectively. Data analysis was performed using SAS 9.4 software, and means were compared using Duncan's test at the 5% probability level.
Results: The results showed that the highest plant height (24.1 cm), number of tillers (6), spike length (14.3 cm), and number of spikes per plant (27.7) were achieved under the 100% water requirement treatment and the March 25 sowing date. Additionally, the highest number of seeds per plant (1245), seed yield (1876 kg. ha^-1), and biological yield (5357 kg. ha^-1) were observed under the same treatment. The highest harvest index (35.9%) was recorded with the 100% irrigation treatment and the March 10 sowing date. Furthermore, the maximum thousand-seed weight was obtained under the 80% water requirement (1.94 g) and the March 25 sowing date (1.88 g). Moreover, the highest mucilage content was reported under the 100% water requirement (23.9%) and the March 10 sowing date (22.4%).
Conclusion: Overall, the findings demonstrated that sowing date and irrigation level significantly affect the growth and yield characteristics of psyllium. Delayed sowing and reduced irrigation levels led to significant declines in plant height, yield components, seed yield, biological yield, and harvest index. Therefore, selecting an optimal sowing date and ensuring adequate water supply can improve the performance of this medicinal plant.

Keywords

• harvest index
• medicinal plant
• mucilage
• number of tillers
• seed yield
• spike length

Main Subjects

• Agriculture and horticulture