Document Type : Research Paper
Authors
- Mehdei Attar Roshan 1
- Afrasiyab Rahnama 2
- Moosa Meskarbashee 1
- Mohammad reza Siahpoosh 3
- Matthew Harrison 4
1 Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz
2 Associate Professor, Department of Plant Production and Genetics, Faculty of Agriculture, Shahid Chamran University of Ahvaz, Iran
3 Department of Plant Production and Genetics, Shahid Chamran University of Ahvaz
4 Tasmanian Institute of Agriculture, University of Tasmania, Newnham Drive, Launceston, Tasmania, Australia
Abstract
Extended abstract
Introduction
Sesame (Sesamum indicum L.) is one of the oldest oilseed crops cultivated for purposes relating to industry and household consumption. It is widely grown in tropical and subtropical regions around the world. Sesame productivity can be highly variable depending upon the growing conditions, cultivars, and cultural practices. Sowing date is a critical field crop management practice that influences the intensity of other practices applied in crop growth and production. Grain yield significantly influences by sowing date and cultivar. The optimal sowing date is one of the most important and low cost field management practices affecting crop growth and yield. In general, early sowing dates correspond to higher growth and grain yields. The aim of this study was to explore an optimum sowing date for new indehiscent sesame cultivars and obtain new superior cultivars with the highest yield potential and adaptation to different sowing date in Dezful region.
Materials and Methods
In order to study the effects of different sowing dates on phonological traits, photosynthetic parameters, and grain and oil yields of dehiscent and indehiscent sesame cultivars, a field experiment was carried out in a split plot arrangement in randomized complete block design with four replications in 2021-2022. The study site was located in Dezful, Iran. The main plots included three sowing dates, June 5, June 20, and July 20, and the sub-plots consisted three indehiscent (Chamran, Mohajer, Barkat) and one dehiscent (Schewin) sesame cultivars. 5 th June sowing date was considered as early sowing date, and 5 th July sowing date was considered as early sowing date. The data regarding plant heigh, height of the first capsule, length of capsule bearing zone, days to the first capsule emergence, days to flowering, stomatal conductance, photosynthetic rate, transpiration rate, chlorophylle index, grain yield, biological yield, harvest index, oil content and oil yield was recorded.
Results and discussion
Significant genotypic differences in phenological traits, photosynthetic parameters, and grain and oil yields were observed among cultivars and across treatments. Different sowing dates differently influenced photosynthetic properties, phenological traits, and grain and oil yields of sesame cultivars. Sowing dates differently led to significant changes in plant heigh, height of the first capsule, length of capsule bearing zone, days to the first capsule emergence, days to flowering, stomatal conductance, photosynthetic rate, transpiration rate, chlorophylle index, grain yield, biological yield, harvest index, oil content and oil yield. In both years. In 2021, 5 th June early sowing date caused a significant decrease in grain yield of Chamran, Schewin, Mohajer and Barkat cultivars by 1, 25, 11 and 6%, respectively, compared to 20 th June sowing date, while 5 th July late sowing date caused a significant reduction in grain yield of Mohajer and Barkat by 21and 37%, respectively, but increased grain yield of Chamran and Schewin by 12 and 28%, respectively. There was genetic variation in grain and oil yield across cultivars in response to sowing dates. Barkat and Mohajer cultivars with the higher grain yield showed greater grain yield stability in response to early sowing date, when compared to Schwin cultivar.
Conclusion
Overall, the results of this experiment showed that optimum sowing dates from 5 th June to 20 th June is recommended as the optimal sowing date to improve sesame production in humid tropical areas. Moreover, Barkat cultivar had the highest grain and oil yield; it is recommended along with Mohajer cultivar for both early and late sowing date conditions in Khuzestan region.
Keywords: Days to flowering, Oil yield, Photosynthetic rate, Stomatal conductance
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