Investigation of Relationship between Some Quantitative and Qualitative Characteristics Affecting Sesame Yield under Nitrogen, Potassium and Drought Stress

In order to study the relationship between quantitative and qualitative traits with sesame grain yield in nutrient treatments as chemical, biological and nano fertilizers and drought stress, an experiment was conducted as factorial split plot based on randomized complete block design with three repetitions. The experiment factors including irrigation regimes, irrigation withholding at different stages of development based on BBCH, full irrigation and irrigation up 65 and 75 BBCH, three nitrogen fertilizers as nitroxin, urea and combination with nitroxin and 50 % urea and four combinations of potassium fertilizer, as non-fertilized as control, spraying and soil application of potassium nano-chelate (2 ppt and 2 kg.ha-1 respectively) and potassium dioxide (2 l.ha-1). The highest grain yield was obtained in irrigation up to 50 % seed ripping in non-application of potassium and use of nitroxin with average of 1340.5 kg.ha-1 that about 35 % increased the average of this trait compared to the control treatment. The grain yield was positively and significantly correlated with stem diameter, plant dry weight, number of capsules, number of seeds per capsule, 1000-seed weight and oil percentage and yield. There was no significant correlation between morphological and yield traits. The results of stepwise regression showed that the maximum grain yield difference can be attributed to the total number of capsules, 1000 seed weight, number of seeds per capsule, oil yield and oil percentage which explained 91.1 % of the grain yield changes. The application of potassium nano- chelate in irrigation withholding at 50 % seed ripening (equivalent to 75 BBCH) and using of nitroxin bio-fertilizer had the highest grain yield in second cultivation after wheat and is suitable for dry and semi-arid climates.