Abstract: (26 Views)
Background and Objective: Drought stress is the most important limiting factor for rapeseed yield in dryland areas, and tolerant cultivars based on physical indices are a solution to reduce this assessment. This study aimed to evaluate qualitative and biochemical indices as biomarkers of tolerance and identify drought-tolerant rapeseed genotypes.
Methods: : The experiment was conducted in a split plot in a randomized complete block design with three replications and in two crop years. The main factor included three irrigation regimes (full irrigation, irrigation interruption at flowering stage and irrigation interruption at pod stage) and the subfactor included 11 canola genotypes. The measured traits included oil yield, fatty acid profile and seed glucosinolate content.
Results: Drought stress, especially at the flowering stage, significantly reduced oil yield. Among the 11 genotypes studied, Jerome (under post-flowering stress) and Saffar (under post-flowering stress) cultivars were identified as drought-tolerant genotypes due to their greater stability in maintaining oil yield and limited changes in fatty acid profiles. In contrast, Zafar cultivar showed the most sensitive biochemical response with a 148.7% increase in erucic acid and a 32.6% decrease in palmitic acid. The Julius and RGS003 cultivars, despite being more sensitive to stress, also produced the highest oil yield under full irrigation conditions.
Conclusion: Drought tolerance in canola does not necessarily equate to high yield potential. The Jerome and Saffar genotypes, with their metabolic stability mechanism, are recommended for cultivation in areas prone to late-season stress, while the Julius and RGS003 cultivars are good choices for fully irrigated conditions. Therefore, selecting the right cultivar for water-deficit areas requires simultaneous consideration of “physiological tolerance” and “yield potential.”