Effect of Irrigation Interval on Morphological, Yield Components and Seed Oil Characteristics of Evening Primrose Plant (Oenothera biennis L.) in Field Conditions

Climate change and inappropriate management activities have put pressure on limited freshwater resources. Water scarcity has led to better allocation of irrigation and it is expected that the allocation of water to the plant is planned according to the environmental conditions and growth stage of the plant. In order to investigate the effect of irrigation interval on morphological characteristics, yield components, yield and oil content on Evening Primrose (Oenothera biennis L.) plant, an experimental was carried out in randomized complete block design with five replications at Khorasan Razavi Agricultural Research and Education Center in 2019. Treatments included: irrigation intervals at three levels of 7, 10 and 14 days. The results showed the highest number of canopy (2833 cm2), dry weight of areal part (98 g/plant) and yield components, highest number of capsules per plant (427), seed weight per plant (5.33 g), grain yield per hectare (1921 kg), oil percentage (0.73%) and oil yield per hectare (275 kg) resulted from 10 days irrigation interval. With increasing irrigation interval from 7 days to 10 days was increased values in aforementioned traits and all studied traits was decreased by incremental irrigation interval from 10 days to 14 days. It seems that cultivated media containing fine textured soil due to the increase in surface area of soil constituents to their unit of weight has improved the favorable growth conditions in 10-day irrigation compared to 7-day irrigation. Therefore, application of irrigation treatment in 10 days increased water productivity efficiency in evening Primrose Flower in Mashhad weather condition.