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Evaluation of seed yield and oil quality of rapeseed (Brassica napus L.) cultivars in autumn and winter sowing under terminal drought stress conditions
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Amir Hossein Shirani rad    , Nadia Safavi Fard |
| Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization, Karaj, Iran |
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Abstract: (37 Views) |
Introduction: Winter sowing of spring cultivars is one of the strategies for sustainable rapeseed production under climate change conditions. It is a simple, low-cost approach that can be implemented on a large scale. Considering the limited canola sowing window in cold-temperate regions and the overlap between the final irrigations of spring crops and the initial irrigations of autumn-sown canola, shifting canola planting from autumn to winter, as a climate-smart strategy, is practical and operationally feasible.
Materials and Methods: A field experiment was carried out as factorial split-plot arrangements in randomized complete block design with three replications in 2021-22 and 2022-23 growing seasons at the Seed and Plant Improvement Institute (SPII), Karaj, Iran. Two planting seasons (autumn on Oct.22 and winter on Feb.19) were assigned to the main-plots, and two irrigation levels (full irrigation as control and irrigation withhold from the silique formation stage as terminal drought stress). Four spring rapeseed cultivars, Dalgan, Saffar, Asa, and Aram were randomized in the sub-polts.
Results: Results showed that in autumn planting and under full irrigation regime, cv. Dalgan with 4115 kg.ha-1 and under drought stress, cv. Delgan and cv. Aram with 3512 kg.ha-1 and 3520 kg.ha-1, respectively, had the highest seed yield. In winter planting and full irrigation, cv. Delgan and cv. Asa with 2568 kg.ha-1 and 2529 kg.ha-1, resepectively, and under drought stress cv. Saffar had the highest seed yield. Under full irrigation regime, cv. Delgan had the highest oil yield (979 kg.ha-1), oleic acid content (59.9%), erucic acid (0.373%) and glucosinolate (19.3 μmole.g-1) and under terminal drought stress, cv. Saffar had the highest oil yield (728 kg.ha-1), oleic acid content (57.2%) and standard levels of erucic acid content (0.635%) and glucosinolate (26.1 μmole.g-1), and were identified suitable for winter season planting.
Conclusions: Given the increasing frequency of temperature fluctuations, terminal droughts, and changing precipitation patterns in cold-temperate regions in Iran, winter planting of canola, when coupled with the selection of suitable and adapted cultivars can be considered as a strategy to reduce water consumption while maintaining the economic yield and oil quality. The results of this study showed that winter planting of spring rapeseed cultivars in cold-temperate and semi-arid regions by taking advantage of winter rainfall, reduced water consumption by 35-40% compared to autumn planting with stable fatty acid composition and standard levels of erucic acid and glucosinolates. These findings underscore the strategic importance of winter planting season in cold-temperate and semi-arid regions and similar agro-ecologies in Iran.
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| Keywords: Drought stress, Glucosinolate, Growing season, Oleic acid and Spring rapeseed |
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Full-Text [PDF 565 kb]
(22 Downloads)
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Type of Study: Scientific & Research |
Subject:
Special
Received: 2026/02/18 | Accepted: 2026/08/27 | Published: 2025/12/1
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