National demand for sesame (Sesamum indicum L.) is strong and growing. For the past 60 years, Texas, Oklahoma, Arizona, and Kansas were the major sesame producing states (Langham 2007). However, these states have been unable to meet the growing demand due to extreme weather conditions and limited acreage (Grichar et al. 2011). Consequently, the United States became a major importer of sesame. In 2021, we imported 37,000 tons of sesame seed, which were worth $82.3 million (FAO STAT 2023). There is a need and growing interest in exploring new, suitable areas for sesame production, particularly in the Southeast, where there is a warm, long growing season and greater annual precipitation as compared to the Southwest (Gloaguen et al. 2018). By expanding domestic sesame production, the United States can reduce its reliance on imported seed while also bolstering our farming communities.

Commercial sesame production uses traditional small grain equipment. The crop is planted with a grain drill or planter and harvested with a combine. Small grain farmers who decide to add sesame to their rotations do not require new equipment or infrastructure. Although sesame may fit into southeastern row crop systems, there are no agronomic recommendations for this region. More in-depth research is necessary to assess the feasibility of sesame production and the basic crop needs

We conducted field trials in 2021 and 2022 in North Carolina to evaluate the performance of sesame, establish nitrogen rate recommendations, and determine the appropriate row spacing requirements. These trials were conducted at the Horticultural Crops Research Station (Clinton), Piedmont Research Station (Salisbury), and Sandhills Research Station (Jackson Springs) in 2021. In 2022, we repeated the trials at Salisbury and Jackson Springs, and at the Tidewater Research Station (Plymouth). In both the variety and the row spacing trials, we applied 35 lb N/ac approximately one week before planting and 35 lb N/ac six weeks after planting. We planted with a small plot drill (7.5 in. row spacing for the variety and nitrogen rate trials) at a constant population of approximately 225,000 seeds/ac. The seed depth ranged between 1 and 1.5 in. based on the soil moisture. All plots were 5 ft wide and 20 ft long. The fields were irrigated one day before or after planting to achieve the soil moisture necessary for seed germination.

The row spacing trial evaluated the effect of three different plant spacing treatments (7.5, 15, and 30 in.) for the sesame variety ES103. The variety trial included nine commercially available varieties of sesame (Table 1).

*Agronomic trait information was extracted from each company’s variety information available for the growers. NA = Not Available.

The nitrogen trial evaluated the effect of five nitrogen fertilizer rates (0, 50, 100, 150, and 200 lb N/ac) for the sesame variety ES103. We used urea (46-0-0 SUPERU™) as our nitrogen source, which was split-applied with 50% at planting and 50% three weeks after planting.

Harvest occurred 15 to 21 weeks after planting in 2021 and 16 to 21 weeks after planting in 2022 with a small plot combine. We used glyphosate or saflufenacil as harvest aids to terminate and desiccate the crop 3 to 7 days before harvest. We calculated yield with the total weight, width and length of the harvested area, and moisture provided by a grain gauge on the combine for each plot. When the plot weights were low and the grain gauge did not provide moisture, we measured the moisture with a grain moisture tester. ↲

2021 versus 2022

We experienced several challenges and difficult lessons in the 2021 field season. We needed to replant every location that year because we did not place the seed at the correct depth. Although sesame planting depth is counterintuitive, the seed is small and must be planted deeply. The sesame seed must sit in a layer of moist soil for at least three days. If at any point during those three days the soil becomes dry, the seed will die. Thus, seeds should be planted at least 0.25 to 0.50 in. below the layer of moisture to a final soil depth of 1 to 1.5 in.

Crusting was also an issue that we experienced at one location. Sesame can emerge from a quite deep soil depth but it cannot break through a crust. If a rain event is predicted near planting, it is critical to plant after precipitation and not before. In Clinton and Sandhills in 2021, we saw pre-emergent herbicide damage. The Dual Magnum (S-metolachlor) that we applied at both locations caused significant phytotoxicity. Unfortunately, there are very few herbicides labeled for use with sesame. We recommend that farmers begin as clean as possible via stale seed bedding or an appropriate burndown. Yields and overall stands were significantly improved in 2022 after we addressed all the planting depth and herbicide issues.

Row Spacing

We did not observe any significant differences in yield for any of the locations in either year (Table 2). Yields in Clinton 2021 averaged the lowest with 154 lb/ac compared to the other environments in the same year, where yields ranged from 574 to 643 lb/ac. Due to environmental conditions and better agronomic practices, yields in 2022 were higher with ranges from 751 to 977 lb/ac (Table 2).

Lack of a row-spacing effect on yield, which is consistent with previous work, is a result of sesame’s phenotypic plasticity. When planting in narrow row spacing, sesame plants are tall, very thin, and single-stemmed. When the row space is widened, the plants branch out and are shorter. (See Figure 1). Regardless of the plant architecture, the yields are the same. This allows for flexibility in row spacing. In general, although we did not see differences, we recommend using a planter with a wider (> 7 in.) spacing. Planters tend to have better depth control than drills, which is critical for proper seed placement. Wider spacing also allows for early season cultivation to reduce weed pressure, which can be a crop-saver when there are such limited weed control options. In addition, the shorter, branched plants produced with wide spacing are less prone to lodging in which the stems bend over near the ground.

Variety Trial

We did not observe differences in yield among varieties in Clinton or Jackson Springs 2021 (Table 3). Yields in Clinton averaged 221 lb/ac, which were exceptionally low due to the herbicide damage. Excessive precipitation and herbicide carryover also affected the crop performance throughout the growing season. In Jackson Springs, the average yield was 484 lb/ac, which we attribute to preemergent herbicide damage and poor stands. The lack of differences in these locations may be due to the environmental and production challenges and are not representative of the variety performance. We found significant differences in yield among varieties in Salisbury in 2021 (P < 0.0001) where S39, S3301, and S3251 were the highest yielding varieties.

Yields in our 2022 variety trials were much higher when we employed improved planting techniques and weed management strategies. Differences were observed among varieties in all three locations. The variety S39 tended to produce the highest yields across the three locations. This variety was not different from varieties S3251 and S3276 in both years and from variety 4302 in 2022. Variety ES108 was often among the lowest yielding varieties, although average yield in 2022 for this variety was 1,218 lb/ac, which is considerably high. The variety SS3301 was one of the poorest producers in Jackson Springs and Plymouth but had the highest yield in Salisbury. This indicates a potential genetics × environment (G × E) interaction, in which certain varieties perform differently in different environments. This G × E interaction in sesame has been observed and warrants further investigation (Langham 2007). We also demonstrated that these sesame varieties show differing rates of resistance to root knot nematodes. (See AG-936, Screening Sesame for Resistance to Multiple Root-Knot Nematode Species.)

When considering a sesame variety, soil nematode tests should be conducted to ensure that the selected sesame variety is resistant to the nematode species that are present.

^[X] Means within a location and year that share a common letter are not significantly different (α=0.05) ↲

^[Y] Varieties 4302 and ES201 were not included in 2021; variety ES107 was not included in 2022. ↲

NA = Not Available ↲

Nitrogen Rate

We observed a typical linear-plateau nitrogen response in Clinton 2021. There was an initial linear increase until it reached a plateau at 98 lb N/ac (Figure 2). Prior to the plateau, the linear response indicated an increase in yield of 1.3 lb/ac for every pound of nitrogen applied. We did not observe a yield plateau in Jackson Springs. Instead, we saw a linear increase in yield where every pound of nitrogen applied resulted in a yield increase of 1.2 lb/ac. Similarly, in Sandhills 2022, we observed a positive linear effect, where yield again increased 1.2 lb for every pound of nitrogen applied. The nitrogen rate did not influence yield in Salisbury in both years and Tidewater 2022.

We believe that the yield response to nitrogen observed in Clinton and Sandhills was due to lower organic matter content in those soils and inherently lower N availability as well as a higher tendency for leaching. The lack of nitrogen effect in yield in Salisbury and Tidewater might be due to higher organic matter content in the soil and reduced leaching. Sesame produces a large root system that is very effective at scavenging nitrogen and other nutrients (Langham 2008). In addition, sesame is highly susceptible to waterlogging and can experience a reduction in growth and yield when grown in poorly drained soil (Uçan et al. 2007). In Tidewater, we observed foliar pathogens and standing water, which affected overall plant health and resulted in early harvest and which may have confounded our nitrogen rate effects. Nitrogen recommendations for Texas and Oklahoma range from 25 lb/ac in dryland conditions with less than 28 in. of rain to 80 lb/ac in fully-irrigated conditions that receive 10 to 12in. of rain (Langham 2008). Given that NC receives considerably more rain than the arid regions of Texas, we recommend application rates between 70 to 80 lb/ac. This is highly dependent on the soil type. Deep sands with low organic matter content may require higher application rates. Care should be taken with split applications of fertilizer to minimize leaching.

Figure 1. A sesame plot in Salisbury, NC that shows the crop’s ability throughout the season to fill in gaps.

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Figure 1. A sesame plot in Salisbury, NC that shows the crop’s ability throughout the season to fill in gaps.

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Figure 2. Nitrogen fertilizer rate effect on sesame yields in 2021 and 2022.

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Figure 2. Nitrogen fertilizer rate effect on sesame yields in 2021 and 2022.

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These research results demonstrate that sesame production in North Carolina is feasible. Yields, particularly in 2022, were comparable to those produced in the Southwest. Variety S39 had the highest yield potential for the Piedmont, Jackson Springs, and Plymouth environments. Other varieties produced lower yields, although their production potential was high. The observed plasticity of this crop affords growers flexibility in the type and setting of their planting equipment. We recommend 15 in. or 30 in. in spacing, which will allow for improved weed control such as cultivation. In addition, sesame will branch out into wider spacing, which reduces the likelihood of lodging. Nitrogen rate results were inconsistent and highly dependent on environmental factors. This study included a single variety (ES103), which was not the ideal performing variety for North Carolina. Thus, the variety used may have confounded the effect of nitrogen on the yield. Further research is needed to investigate the effect of nitrogen rate on different sesame genetics, and to evaluate the appropriate planting date and weed management for this region.

We would like to thank the station staff at the Piedmont, Sandhills, Tidewater, and Horticultural Crops research stations. We would also like to thank the North Carolina Department of Agriculture New and Emerging Crops Program (grant no. 21-062-4005 and 22-036-4004) for funding this work.

Food and Agriculture Organization of the United Nations. [FAOSTAT]. 2023. “Food and Agricultural Data.” Accessed October 3, 2023.

Gloaguen, Romain M., Seth Byrd, Diane L. Rowland, Derald Ray Langham, and Annie Couch. 2018. “Planting Date and Row Spacing Effects on the Agronomic Potential of Sesame in the Southeastern USA.” Journal of Crop Improvement 32, no. 3: 387-417.

Grichar, W. James, Peter A. Dotray, and Derald Ray Langham. 2011. “Weed Control and the Use of Herbicides in Sesame Production.” In Herbicides, Theory and Applications, edited by Sonia Soloneski and Marcelo L. Larramendy, 41-72. InTechOpen.

Langham, Derald Ray. 2007. “Phenology of Sesame.” In Issues in New Crops and New Uses, edited by J. Janick and A. Whipkey,144-182. Alexandria: ASHS Press.

Langham, Derald Ray. 2008. Growth and Development of Sesame. San Antonio: American Sesame Grower Association.

Uçan, Kenan, Fatih Killi, Cafer Gençoğlan, and Hasan Merdun. 2007. “Effect of Irrigation Frequency and Amount on Water Use Efficiency and Yield of Sesame (Sesamum indicum L.) under Field Conditions.” Field Crops Research 101, no. 3: 249–258.