Impact of Combined and Separate Water, Salinity, and Nitrogen Stresses on Morpho-Physiological Traits and Yield Components of Camelina sativa

Abstract

Abiotic stresses such as water, salinity, and nitrogen stresses pose significant threats to crop growth and yield, limiting oilseed production in arid and semi-arid regions. A completely randomized factorial design experiment was conducted to evaluate the morpho-physiology, grain yield, and yield components of Camelina under separate stresses (water, salinity, and nitrogen) as well as combined stresses, including: water and salinity, water and nitrogen, salinity and nitrogen, and the simultaneous application of water, salinity, and nitrogen. Treatments consisted of five salinities (1, 2, 4, 6, and 10 dS/m), three irrigation levels (100%, 75%, and 50% of field capacity), and three nitrogen concentrations (100%, 75%, and 50% of the recommended nitrogen dose), each with three replicates. The variance analysis results indicated that separate water and salinity stresses significantly affected grain yield and oil percentage at the 5% significance level. Furthermore, combined stresses-such as water and salinity, water and nitrogen, and the combination of water, salinity, and nitrogen -had a significant effect on oil percentage at the 1% level. The combined effects of water, salinity, and nitrogen also significantly impacted grain yield at the 5% level. Mean comparisons revealed that grain yield increased up to 75% field capacity, after which it decreased. The highest grain yield and oil percentage were recorded at a salinity level of 4 dS/m. Nitrogen deficiency reduced the leaf greenness index, decreased radiation absorption, hindered plant growth, and reduced the leaf area index. Overall, at certain thresholds of salinity, water and nitrogen, an increase in yield and yield components can be observed, suggesting the presence of tolerance levels for these abiotic stresses.