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Effect of cytokinin hormone on morphological and yield traits of sunflower under terminal heat stress
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Mahbobeh Khajavi *   , Afrasyab Rahnama , Moosa Meskarbashee , Seyed Amir Moosavi , Matthew Tom Harrison |
| Department of Plant Production and Genetics, Shahid Chamran University of Ahvaz, Ahvaz, Iran |
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Abstract: (391 Views) |
In order to study the effect of cytokinin hormone on morphological, grain and oil yield traits of sunflower under terminal heat stress, a field experiment carried out in a split plot factorial in randomized complete block design with three replications at the research farm of Shahid Chamran University of Ahvaz in 2021. Main plots consisted of three sowing dates; February 3, February 18, and March 5 (Normal, delayed and late sowing dates, respectively), and sub plot consisted of factorial arrangement of different concentrations of cytokinin (0, 25 and 50 and 75 μm l-1, Kinetin), and sunflower cultivars (Qasem and Oskar). Sowing date with desired temperature was considered as control, and delayed and late sowing dates were considered as mild and severe heat stress. In delayed and late sowing dates, the flowering and grain filling periods of cultivars were exposed to mild and severe heat stress at the end of growing season. Heat stress in delayed and late sowing dates caused a significant decrease in plant height, grain number per head, head diameter, 1000-grain weight, biological yield, oil percentage, and oil and grain yield. The optimum hormone concentration needed to exhibit a considerable increase in studied traits of sunflower cultivars under heat stress was 50 μm l-1, particularly, in late sowing date sunflower plants, foliar application of cytokinin (50 μm l-1) enhanced grain yield (by 17% and 15%), biological yield (by 29% and 22%), and oil yield (27 and 18%), in Oscar and Qasem cultivars, respectively, when compared to cytokinin-deficient plants. Based on the results of this research, foliar application of cytokinin (50 μm l-1) can be recommended as a strategy to enhance the grain and oil yield of sunflower cultivars under heat stress conditions in tropical regions such as Khuzestan. |
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| Keywords: Key words: Foliar spraying, heat stress, kinetin, oil yield |
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Full-Text [PDF 1315 kb]
(297 Downloads)
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Type of Study: Research |
Subject:
Crop Physiology
Received: 2023/03/1 | Accepted: 2023/03/1 | Published: 2023/03/1
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