|
Evaluation of biochemical traits and seed yield of sunflower (Helianthus annuss L.) cultivars in response to terminal heat stress in Ahvaz, Iran
|
Behnoosh Sheikh Mamo   , Afrasyab Rahnama , Payman Hassibi |
| Associate Prof., Shahid Chamran University of Ahvaz, Ahvaz, Iran |
|
|
Abstract: (214 Views) |
Introduction: Climate change is a very serious threat to crops production in all regions around the world. Heat stress is a consequence of climate change that affects biochemical, physiological and molecular processes of crop plants, causing alterations in crop growth, development, and productivity. Terminal heat stress is the most widespread and type of heat stress in the world that limits crop productivity and ultimately food security. Sunflower is moderately tolerant to heat stress. It can tolerate higher temperatures without suffering from heat stress. However, sunflower is more susceptible to heat stress from early flowering to grain filling. Hence, it may be severely damaged when exposed to terminal heat stress. Biochemical and physiological responses in crop plants are modified under heat stress. It has been shown that tolerance to heat stress in crop plants is associated with an increase in antioxidant enzyme activities. The physiological and biochemical responses to heat stress vary among crop plant species and genotypes which can be used for development of cultivars with high temperature tolerance in crop plants.
Materials and Methods: This experiment was carried out in 2017-2018 growing season in Ahvaz, Iran, using as split-plot arrangement in randomized complete block design with three replications. Main plots consisted of three sowing date including; 11th November, 11th December and 11th Janauary, and five sunflower cultivars including; Qasem, Fantasia, Shams, Lakomka and Progress were randomized in sublpots. Sowing on 11th November was considered as normal sowing date, and sowing on 11th December and 11th January were delayed and late sowing dates, respectively. In the two latter sowing dates, flowering and grain filling periods were exposed to moderate and severe terminal heat stress.
Results: Terminal heat stress in delayed and late sowing dates caused significant reduction in carotenoid content (27% and 56%, respectively), seed yield (30% and 32%, respectively) and oil yield (18% and 28%, respectively), but increased catalase (63% and 55%, respectively), peroxidase (107% and 56%, respectively) and superoxide dismutase (43% and 67%, respectively) enzyme activities, carbohydrate concentrations (18% and 30%, respectively) and malondialdehyde concentration (46% and 98%, respectively), when compared to normal sowing date. There was significant differences among sunflower cultivars for most of studied traits. Lakomka cultivar with the highest values of biochemical and physiological indices such as chlorophylle content, antioxidant enzyme activities and carbohydrates concentration and with the lowest malondialdehyde concentration had the highest seed yield (1579 kg.ha-1) and oil yield (608 kg.ha-1) under terminal heat stress.
Conclusion: Exposure to moderate and severe terminal heat stress differently influenced physiological and biochemical traits in sunflower cultivars. The severity of terminal heat stress played an important role in the cultivars responses. Progress cultivar had the lowest reduction in oil and seed yield under terminal heat stress, however, cv. Lakomka showed highest seed and oil yield in all three sowing dates. Therefore, it can be concluded that cv. Lakomka is suitable for being sown in normal, delayed and late sowing dates due to least variability in its seed yield.
|
|
| Keywords: Antioxidant activity, Heat stress, Seed oil content, Soluble carbohydrates and Sunflower |
|
|
Full-Text [PDF 804 kb]
(65 Downloads)
|
Type of Study: Scientific & Research |
Subject:
Special
Received: 2023/10/17 | Accepted: 2024/02/4 | Published: 2024/02/29
|
|
|
|
|
|
|
| Send email to the article author |
|
|
|
| Add your comments about this article |
|
|
|
