Study of Planting Density on Agronomic Traits of Sesame Cultivars

Sesame (Sesamum indicum L.) is considered as the queen of oilseeds for its high oil quality. Sesame oil is rich in micronutrients, antioxidants and essential amino acids as well as polyunsaturated fatty acids. It has been well documented that agronomic practices such as time and rate of planting will have a direct effect on sesame grain yield, oil content and quality. Therefore determining the optimum plant density is very important in sesame production.
Material and In the current experiment, the effect of different planting densities (20, 40 and 60 Plants per m2) was investigated on agronomic traits of six sesame cultivars (Halil, Dashtestan 2, Darab 1, Oltan, Yellow White and Naz Tak Shakhe). The field experiment was carried out as factorial layout based on randomised complete block design with three replicates in research farm of Seed and Plant Improvement Institute, in 2016. Each experimental plot consisted of four adjacent rows, 5 m in length and 0.3 m apart. To achieve the above-mentioned planting densities, sesame seeds were sown 16, 8 and 5 cm apart on each row on 6th June. If required, the seedlings were thinned at 2-3 leaf stage. The crop was irrigated according to the conventional schedule for the region. Weeds were manually removed throughout the growing season. At physiological maturity stage, two middle rows of each plot were harvested for determination of yield and yield components. Data analysis was performed using SAS 9.1 and means were compared by the Least Significant Difference (LSD) test at the 5% probability level. The results showed that all measured traits except 1000-seed weight and harvest index significantly affected by planting density. Also, the interaction between planting density and cultivar was significant on the number of capsules per plant, seed yield, harvest index and oil concentration. At planting densities of 20 and 40 plants per m2, the maximum grain yield were related to Dashtestan 2 cultivar. At planting densities of 60 plants per m2, Naz Tak Shakhe was found to be the best cultivar regarding grain yield. Although the increase in planting density from 20 to 40 plants per m2, could increase grain yield in all cultivars, the highest grain yield was related to Naz Tak Shakhe cultivar. Furthermore, increase in planting density up to 60 plants per m2, caused severe grain yield loss in all cultivars except Naz Tak Shakhe cultivar which showed 18% increase in grain yield. In general, it can be concluded that cultivars characteristics could be considered as essential parameters to determine the optimum planting density. Therefore, if the plant density is adjusted in such a way that plants could be able to use the environment and agronomic inputs factors with the minimum intra-specific competition, maximum economic yield will be obtained