The effect of different irrigation and salicylic acid applications on yield and quality of linseed (Linum usitatissimum L.)

Linseed is an important oilseed crop with multipurpose uses. However, drought stress poses a serious threat to sustainable agricultural production and global food security. Plant growth regulators such as salicylic acid (SA) have been reported to alleviate the adverse effects of drought stress in plants. This study was conducted as a pot experiment under controlled environmental conditions to evaluate the effects of SA application on the yield and quality of linseed under drought stress. The experiment was arranged in a split-plot design with four replications, including four irrigation levels (I25, I50, I75, and I100) and five SA doses (0, 25, 50, 75, and 100 mg L-¹). Drought stress significantly affected all evaluated morphological, physiological, and yield related traits, confirming water availability as a key determinant of plant growth. Increasing irrigation levels improved SPAD value, relative water content, stomata characteristics, number of capsules per plant and number of seeds per capsule, seed yield per plant, thousand seed weight, and root traits. SA application caused significant changes in physiological and yield parameters, and interaction effects indicated that SA may enhance plant performance under drought conditions. Seed oil content ranged from 32.39% to 40.01%, with drought stress and higher SA doses increasing oil concentration. The predominant fatty acids were linolenic, oleic, and linoleic acids. The findings show that SA administration may be an effective strategy to increase yield and quality in linseed cultivation under drought conditions.