Investigating response of yield traits and oil content of sesame variety (Sesamum indicum L.) to nano-magnesium fertilizer and biopolymer chitosan under limited water stress

Sesamum, scientifically named Sesamum indicum L., is one of the oldest oilseed families and is adapted to warm and semi-warm regions and is known as the queen of oilseeds. The use of nanotechnology in the production of fertilizers results in optimal release and increased efficiency of absorption of nutrients in fertilizer which leads to significant economic and environmental benefits. Chitosan elicits stimulating defense mechanisms and is beneficial to plants, animals and humans and is environmentally friendly. Due to the fact that water stress and dehydration in Iran is always one of the most important agricultural problems and due to the importance of magnesium in photosynthesis of plants and also the use of different polymers such as chitosan to reduce the damage caused by stress, this study aimed to evaluate the effect of nano chitosan and magnesium application under water stress conditions on some sesame traits for sustainable agriculture development in Varamin region.

In order to evaluate limited water stress and foliar application of magnesium and chitosan on growth and yielding traits and oil content of two sesame varieties, an experiment was conducted as a split factorial based on completely randomized blocks designed with three replications in a research farm in the southern Varamin Province, Iran, during 2016-17 growing season. Irrigation cut-off based on BBCH scale in three-level included: normal irrigation, 65 BBCH (flowering), and irrigation cut-off in 75 BBCH (capsule maturity) as the main factors. Sub-plot included a combination of three factors: two genotypes Oltan and Dashtestan-2, foliar application of Mg-nano in two levels non-application and foliar application (2 g/L) in 65 BBCH stage and foliar application of chitosan in three levels: non-application, foliar application of 4.8 g/L in 65 BBCH stage and 6.4 g/L in 75 BBCH stage.

The results showed that the irrigation up to 65 BBCH caused a reducing 28.08, 20.8, 53.05, 54.04 and 23.10% in the average traits of number of capsules, 1000-grain weight, grain yield, LAI, and oil percentage content in compared to the normal irrigation treatment (control). The highest grain yield was achieved in the application of Mg-nano-fertilizer under normal irrigation in Dashtestan-2 variety with a mean of 1188.2 kg/ha, which 16.3% increased in compared to the control treatment. The highest oil percentage was observed in the application of Mg-nano under normal irrigation was in Dashtestan-2 variety with an average of 50.38%, which 3.5% increase in compared to the control treatment.The highest grain yield was achieved in the application of Mg-nano-fertilizer under normal irrigation in Dashtestan-2 variety with a mean of 1188.2 kg/ha, which 16.3% increased in compared to the control treatment. The highest oil percentage was observed in the application of Mg-nano under normal irrigation was in Dashtestan-2 variety with an average of 50.38%, which 3.5% increase in compared to the control treatment.

Finally, foliar application of Mg-nano and chitosan (4.8 g/L) under water stress conditions were able to compensate for damage and to modify the negative effects of stress.