**4. History of sesame harvest aids**

Gollifer and Radley [26] studied the use of diquat-dibromide (a desiccant) at 3.5 L ha<sup>1</sup> and endothal (a defoliant) at 8.2 L ha<sup>1</sup> using the Venezuela 51 sesame variety in Trinidad at 78 and 88 days after planting. These applications reduced yield, moisture, and oil content. For the first application there were reductions in sesame yield (35%), seed weight (12%) and oil content (14%). Also, endothal reduced germination 16%. There were no appreciable differences at the 88 day after planting application between the two herbicides. The diquat-dibromide was a good desiccant while the endothal was not an effective defoliant.

Perez and Gonzalez [27] evaluated 1% paraquat-dichloride as a harvest aid compared to the untreated check using one variety (Morada indehiscente) at three timings in Venezuela. They concluded that there was no difference in yield, but there was in oil content.

Urdaneta and Mazzani [28] studied the effect of diquat-dibromide at 1.5 and 2 L ha<sup>1</sup> with different surfactants (JF-4825, JF-4826, and Agral 90) applied 96 and 103 days after emergence (DAE), using one variety (Aceitera R) in Venezuela. They concluded that diquat-dibromide at 1.5 L ha<sup>1</sup> resulted in a higher yield than at 2.0 L ha<sup>1</sup> ; yield from the 103 DAE application was greater than the 96 DAE application; there were differences in the surfactant used; harvesting plots without a harvest aid at the same time as the application of harvest aids yielded less than the application of the harvest aids; and there were no differences in germination of the seed harvested from treated and untreated plants.

Lee [29] sprayed two concentrations (0.3 and 0.5%, v/v) of diquat-dibromide on one variety in South Korea. Both concentrations reduced sesame moisture content and increased capsule dehiscence. He concluded diquat-dibromide could be used as a harvest aid to accelerate desiccation up to 2 weeks from normal field conditions.

In South Korea, Han et al. [30] applied diquat-dibromide and paraquatdichloride at 250, 500, and 1000 ppm on sesame 3 days or 3 h before cutting the plants. The moisture content decreased rapidly while yield and germination were not different from untreated check. There were no detectable diquat-dibromide or paraquat-dichloride residues when sprayed at 250 ppm 3 days before cutting but there were higher residues for all other concentrations and for the 3 h before cutting application. There was 25% less labor required in threshing the diquat-dibromide and paraquat-dichloride treated plots as opposed to the untreated and 100% of the seed was recovered in 9 days as opposed to 12 days for the untreated.

In Australia, Bennett [31] studied the effects of diquat-dibromide applied 81, 86, and 89 days after planting (DAP) and rates (1.2, 2.2, and 4.5 L ha<sup>1</sup> ) in 1992 and 1993 using the sesame variety, Yori 77. He concluded that diquat-dibromide dried the sesame quicker than natural drydown and stem moisture was higher than the seed moisture. The greener stem could be a problem in combining in that the sap from the stems could coat the seeds and give them a bad flavor. There was less sap when the stems reached 10% moisture; however, it could take an additional 7 days

#### *Effects of Harvest Aids on Sesame (*Sesamum indicum *L.) Drydown and Maturity DOI: http://dx.doi.org/10.5772/intechopen.91011*

for the stem to reach this moisture level leading to more seed loss in the field. Also, desiccation did not have an effect on defoliation, and the ability to harvest earlier through desiccation increased seed yield. In a grower book, Bennett et al. [32] recommended a diquat-dibromide application of 3 L ha<sup>1</sup> . This application rate reduced shattering but seed loss was still evident even while waiting for sufficient drydown to spray (**Figure 8**). Also, there was still more loss when the cutter bar struck the sesame and the sesame was being moved by the auger into the feeder housing of the combine.

Bennett and Routley [33] studied diquat-dibromide at 0, 1.4, 2.6, and 5.3 L ha<sup>1</sup> and time of application (97 DAP with 40% green capsules, 103 DAP with 18% green capsules, 109 DAP with 0% green capsules, and untreated) in the 1993 and 1994 growing season using the sesame variety, Y1:44. Results indicated that application rates of 2.0 L ha<sup>1</sup> were cost effective and that time of application should be between 20 and 40% green capsules. They also concluded that desiccation was a risk management tool. Sesame naturally drying down can be exposed for 30–40 days of various weather conditions, including rains and high winds**,** while a desiccated crop has a drydown of 7–10 days and, therefore, less of a chance of being exposed to inclement weather conditions. Also, desiccation allows the grower to plan for contract harvesting and trucks.

Mazzani [34] summarizing sesame research in Venezuela stated after almost 30 years of research and grower experience, the recommendations were to use diquat-dibromide at 1 kg ha<sup>1</sup> at normal cutting time, which resulted in only a 15% lower yield over the untreated. Applying diquat-dibromide at 2 kg ha<sup>1</sup> a week earlier than normal cutting time resulted in 97% seed loss due to immature seeds. The desiccation system is 4–8% of the cost of traditional system of cutting, binding, and shocking. Mazzani (personal communication, 1999) said that the timing of the herbicide application required grower experience of the sesame maturity stage based on capsule color and variety instead of number of days from emergence. Also, combining after using diquat-dibromide could be a bit earlier than the traditional method. Using the traditional shocking method, the inner bundles in the shocks take longer to drydown resulting in high risk, since the start of the monsoon season can occur while the sesame is still in shocks. One of the major advantages of using desiccants is that there is less manual labor available at harvest for cutting and shocking. On the negative side, the use of desiccants may produce less yield than the traditional method, particularly if there is a wind during drydown, which may cause

**Figure 8.** *Sesame on the ground even before combining from using dehiscent varieties (Photo: M. Bennett).*

the ground instead of shocking it manually. The windrows were harvested with a combine equipped with a pickup attachment. By 1988, the shatter resistance had improved to the point where the sesame could be left in the field to dry and then cut. The goal had been to have the seeds stay in the capsules until the combines arrived and then release the seed in the combine with a minimum of force. Improvements continued with the development of non-dehiscent sesame [24, 25] and later improved non-dehiscent sesame [25]. The seed would stay in the capsules through wind and rain even after the plants were dry enough to combine (**Figure 7**).

*Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production*

Gollifer and Radley [26] studied the use of diquat-dibromide (a desiccant) at 3.5 L ha<sup>1</sup> and endothal (a defoliant) at 8.2 L ha<sup>1</sup> using the Venezuela 51 sesame variety in Trinidad at 78 and 88 days after planting. These applications reduced yield, moisture, and oil content. For the first application there were reductions in sesame yield (35%), seed weight (12%) and oil content (14%). Also, endothal reduced germination 16%. There were no appreciable differences at the 88 day after planting application between the two herbicides. The diquat-dibromide was a good

Perez and Gonzalez [27] evaluated 1% paraquat-dichloride as a harvest aid compared to the untreated check using one variety (Morada indehiscente) at three timings in Venezuela. They concluded that there was no difference in yield, but

Urdaneta and Mazzani [28] studied the effect of diquat-dibromide at 1.5 and 2 L ha<sup>1</sup> with different surfactants (JF-4825, JF-4826, and Agral 90) applied 96 and 103 days after emergence (DAE), using one variety (Aceitera R) in Venezuela. They concluded that diquat-dibromide at 1.5 L ha<sup>1</sup> resulted in a higher yield than at

; yield from the 103 DAE application was greater than the 96 DAE application; there were differences in the surfactant used; harvesting plots without a harvest aid at the same time as the application of harvest aids yielded less than the application of the harvest aids; and there were no differences in germination of the

Lee [29] sprayed two concentrations (0.3 and 0.5%, v/v) of diquat-dibromide on one variety in South Korea. Both concentrations reduced sesame moisture content and increased capsule dehiscence. He concluded diquat-dibromide could be used as a harvest aid to accelerate desiccation up to 2 weeks from normal field conditions. In South Korea, Han et al. [30] applied diquat-dibromide and paraquatdichloride at 250, 500, and 1000 ppm on sesame 3 days or 3 h before cutting the plants. The moisture content decreased rapidly while yield and germination were not different from untreated check. There were no detectable diquat-dibromide or paraquat-dichloride residues when sprayed at 250 ppm 3 days before cutting but there were higher residues for all other concentrations and for the 3 h before cutting application. There was 25% less labor required in threshing the diquat-dibromide and paraquat-dichloride treated plots as opposed to the untreated and 100% of the

In Australia, Bennett [31] studied the effects of diquat-dibromide applied 81, 86,

1993 using the sesame variety, Yori 77. He concluded that diquat-dibromide dried the sesame quicker than natural drydown and stem moisture was higher than the seed moisture. The greener stem could be a problem in combining in that the sap from the stems could coat the seeds and give them a bad flavor. There was less sap when the stems reached 10% moisture; however, it could take an additional 7 days

) in 1992 and

seed was recovered in 9 days as opposed to 12 days for the untreated.

and 89 days after planting (DAP) and rates (1.2, 2.2, and 4.5 L ha<sup>1</sup>

**4. History of sesame harvest aids**

there was in oil content.

2.0 L ha<sup>1</sup>

**214**

desiccant while the endothal was not an effective defoliant.

seed harvested from treated and untreated plants.

cool evenings, harvest aids are slower acting and a frost or freeze will dry down the sesame just as effectively as a harvest aid. There are six reasons to consider a harvest

*Effects of Harvest Aids on Sesame (*Sesamum indicum *L.) Drydown and Maturity*

1.**Accelerate drydown.** This is basically using the idea that no weather event can increase yield after the crop is mature, but there are many weather events that can reduce yield. Natural drydown averages 5–6 weeks and inclement weather can prevent a combine from entering a field for as many as 8–9 weeks. With harvest aids, the drydown is 1–2 weeks depending on heat and humidity. In the USA, sesame is grown from the southern-most tip of Texas to the Kansas border. Planting starts in late March in the south and ends in early July in the north while harvest starts in late August in the south and ends in December in

the north. Into the fall and early winter, the daylength shortens and

frost, particularly on late planted sesame.

temperatures cool with a pattern in most areas of increased rainfall. In south Texas, harvest aids will accelerate the drydown and avoid poor weather (particularly the threat of hurricanes along the Texas coast). In the northern part of Texas, Oklahoma, or Kansas, frost will generally kill sesame without having to use harvest aids. There is a gray zone in between where in some years, harvest aids are used and in other years the growers will wait for the

2.**Burn-down green weeds.** Green weeds can add moisture to the sesame seed in the combine bin. As stated above, moisture needs to be around 6% at harvest. Sesame can be dry and yet in the combine bin and the truck, moisture from the weeds can be absorbed by the sesame seed. The two major weed problems are *Amaranthus* spp. and *Echinochloa crus-galli*. *Amaranthus* spp*.* has a lot of moisture in the stems while green *E. crus-galli* seeds will not blow out the back of the combine and will go into the bin with a remarkable amount of moisture.

Certain weeds can be a serious problem in processing sesame. A large percentage of any weed seed can be a problem when cleaning sesame even though it may be as small as *Amaranthus* spp*.* or as large as the seed of *Ipomoea* spp*.* Certain weed seeds such *Sorghum halepense*, *Solanum rostratum*, *Coreopsis* spp., *Salsola tragus, Salvia reflexa, Chenopodium album*, and *Kochia scoparia* are more of a problem, even in small quantities. No one wants any seed, other than sesame, on top of their hamburger bun. Although much of *Sorghum halepense* seed is a different size compared to sesame, the elongated seeds of *Sorghum halepense* can go through the round holes of the cleaner head first. Once through the cleaner, they have a specific gravity close to sesame seed and cannot be easily separated on the gravity table. Finally, a portion will be close enough in color to sesame that it will not be separated by the color sorter. *Solanum rostratum* is the same size and specific gravity as sesame and the seed may not be cleaned out of the sesame. *Salvia reflexa* is a special problem in that

when it contacts water, the seed coat will swell into a sticky gelatinous substance that will clump sesame seeds together. As mentioned by Bennett [31], sap from some weed stems can coat the seeds and give them a bad flavor.

3.**Even up a field with varying levels of drydown.** Many fields have low spots that can still be green while high spots are drying. The difference between the stage of the driest and the stage of the greenest and the proportion between the dry and the green must be considered. In most cases, the "green portions" are 1–2 weeks behind the 'dry portions". In this case, the dry portions should go past PM until the capsules start drying down to allow the green portions to mature further increasing the yield potential. However, if the differences are

aid for use in sesame:

*DOI: http://dx.doi.org/10.5772/intechopen.91011*

**217**

#### **Figure 9.**

*(a) and (b) Spraying of mature sesame with diquat-dibromide to drydown the sesame for direct harvest (Photos: S. Araujo).*

#### **Figure 10.**

*Combining sesame in various countries. US (Photo: J. Riney), China (Photo: H.Y. Zhang), Brazil (Photo: V. Queroga). (a) USA; (b) China; (c) Brazil.*

some seed to shatter or in the case of severe winds most of the seed to shatter. Some growers (L. Jimenez, personal communication, 1998) who have large plantings use both methods since all the fields may be ready for harvest at the same time and there is not enough labor to cut all the sesame at the same time. However, in years when there is asynchronous maturity and labor is available, they prefer cutting instead of applying a harvest aid.

Currently in Venezuela, Araujo [35] reported that two applications of diquatdibromide at 2 kg ha<sup>1</sup> are applied a week apart (**Figure 9a** and **b**).

In the USA, glyphosate has been approved for use as a harvest aid by the Environmental Protection Agency (EPA) and it is used extensively for harvest in the southern USA (**Figure 10a**). In the northern latitudes, glyphosate is not as effective because of possible low temperatures at harvest. In addition, in the northern areas, there are normally frosts or freezes that accelerate drydown.

P. Bazyar (personal communication, 2018) reported diquat-dibromide is currently used as a harvest aid in Iran. Diquat-dibromide is sprayed when 65–75% of the capsules have changed color from dark green to bright green and the crop is harvested with a wheat combine. H.M. Miao (personal communication, 2019) reported either paraquat-dichloride or ethylene (1.5 kg ha<sup>1</sup> ) are used as a harvest aid in direct harvest sesame in Xinjiang Province in China (**Figure 10b**). V. Queiroga and N. Arriel (personal communication, 2019) reported paraquatdichloride or diquat-dibromide are used as a harvest aids in direct harvest sesame in Mato Grosso, Brazil (**Figure 10c**).

#### **5. Rationale for harvest aids in the USA**

In the USA, all the sesame is mechanically harvested with a combine and the use of a harvest aid can help facilitate harvest in most cases. In northern latitudes, with

cool evenings, harvest aids are slower acting and a frost or freeze will dry down the sesame just as effectively as a harvest aid. There are six reasons to consider a harvest aid for use in sesame:


some seed to shatter or in the case of severe winds most of the seed to shatter. Some growers (L. Jimenez, personal communication, 1998) who have large plantings use both methods since all the fields may be ready for harvest at the same time and there is not enough labor to cut all the sesame at the same time. However, in years when there is asynchronous maturity and labor is available, they prefer cutting

*Combining sesame in various countries. US (Photo: J. Riney), China (Photo: H.Y. Zhang), Brazil (Photo:*

*(a) and (b) Spraying of mature sesame with diquat-dibromide to drydown the sesame for direct harvest*

*Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production*

Currently in Venezuela, Araujo [35] reported that two applications of diquat-

P. Bazyar (personal communication, 2018) reported diquat-dibromide is currently used as a harvest aid in Iran. Diquat-dibromide is sprayed when 65–75% of the capsules have changed color from dark green to bright green and the crop is harvested with a wheat combine. H.M. Miao (personal communication, 2019)

In the USA, all the sesame is mechanically harvested with a combine and the use of a harvest aid can help facilitate harvest in most cases. In northern latitudes, with

) are used as a harvest

In the USA, glyphosate has been approved for use as a harvest aid by the Environmental Protection Agency (EPA) and it is used extensively for harvest in the southern USA (**Figure 10a**). In the northern latitudes, glyphosate is not as effective because of possible low temperatures at harvest. In addition, in the northern areas, there are normally frosts or freezes that accelerate drydown.

dibromide at 2 kg ha<sup>1</sup> are applied a week apart (**Figure 9a** and **b**).

reported either paraquat-dichloride or ethylene (1.5 kg ha<sup>1</sup>

aid in direct harvest sesame in Xinjiang Province in China (**Figure 10b**). V. Queiroga and N. Arriel (personal communication, 2019) reported paraquatdichloride or diquat-dibromide are used as a harvest aids in direct harvest sesame in

instead of applying a harvest aid.

*V. Queroga). (a) USA; (b) China; (c) Brazil.*

**Figure 9.**

**Figure 10.**

*(Photos: S. Araujo).*

Mato Grosso, Brazil (**Figure 10c**).

**216**

**5. Rationale for harvest aids in the USA**

more than 2 weeks, the field should be harvested at different times. On the other hand, if the proportion of green is very small, it is not practical to harvest at different times, and the yield loss in the green portion should be acceptable.

There is no set formula to determine the solution. Like most farming decisions, it is up to the judgement of the grower. In some cases, some seed maybe planted in dry soil and only germinate after a rain resulting in two growth stages. The decision to harvest is therefore not clear. A rain 1–2 weeks after planting is different from a rain 4–6 weeks after planting. As stated above, the proportion is also important. If most of the field is of late germination, the early plants should be ignored. In a higher proportion of early germination, the older plants will have a more aggressive root system, shading the younger plants, and therefore the younger plants will act like weeds. The younger plants will not produce a substantial amount of seed and should be ignored in the decision as to when to use harvest aids. Using glyphosate on uneven fields will kill all the sesame and the stage of seed fill will be frozen. Killing sesame while leaves are still attached does cause some problems with dry leaves (particularly the petioles) being broken up and entering the combine bin as foreign matter.

4.**Stop regrowth.** Certain sesame varieties have a propensity for restarting growth and flowering after the main stem has stopped flowering. Regrowth usually occurs in areas where conditions are such that the plants have run out of moisture and/or fertility. If there is rain, some varieties will form branches at the bottom of the plant and these will flower and set capsules while the main stem and the older branches will not start flowering again (**Figures 11** and **12**). There are three types of regrowth: top (restarts at the tops of the main stems), middle (branches emerge from the middle of the main stem), and bottom (branches start in the axils of other branches or below the branches). There are varieties that show spontaneous branching whereby branches start in the middle of the capsule zone under capsules. However, this is not considered regrowth because spontaneous branches begin during flowering and stop flowering before the top of the main stem stops flowering. In regrowth,

capsules on the original plant will dry down while it may take another 60 days for the regrowth capsules to mature and dry out. Since most of the yield is in the old growth, it can shatter while waiting for the regrowth to dry to be combined. Combining when the original plant is dry and the regrowth is green is similar to the weed situation in that it will introduce moisture into the combine bin. Using glyphosate as a harvest aid will kill the plant and stop the

*Middle regrowth (red arrow) in the middle of the capsule zone. Note: the sesame without regrowth is dry. Both of these are minor regrowth which has already stopped flowering. In some cases, there may be over 20 capsules*

*Effects of Harvest Aids on Sesame (*Sesamum indicum *L.) Drydown and Maturity*

*DOI: http://dx.doi.org/10.5772/intechopen.91011*

*In many areas of the world, seed will germinate inside the green capsule when the temperatures are high. Even if only the top seeds germinate, the roots from the seedlings will trap the seeds below, preventing them from being*

regrowth.

**Figure 12.**

**Figure 13.**

**219**

*harvested (Photo: D.R. Langham).*

*on each branch.*

**Figure 11.** *Bottom regrowth (red arrow) below the lowest capsule (yellow arrow).*

*Effects of Harvest Aids on Sesame (*Sesamum indicum *L.) Drydown and Maturity DOI: http://dx.doi.org/10.5772/intechopen.91011*

#### **Figure 12.**

more than 2 weeks, the field should be harvested at different times. On the other hand, if the proportion of green is very small, it is not practical to harvest at different times, and the yield loss in the green portion should be acceptable. There is no set formula to determine the solution. Like most farming decisions, it is up to the judgement of the grower. In some cases, some seed maybe planted in dry soil and only germinate after a rain resulting in two growth stages. The decision to harvest is therefore not clear. A rain 1–2 weeks after planting is different from a rain 4–6 weeks after planting. As stated above, the proportion is also important. If most of the field is of late germination, the early plants should be ignored. In a higher proportion of early germination, the older plants will have a more aggressive root system, shading the younger plants, and therefore the younger plants will act like weeds. The younger plants will not produce a substantial amount of seed and should be ignored in the decision as to when to use harvest aids. Using glyphosate on uneven fields will kill all the sesame and the stage of seed fill will be frozen. Killing sesame while leaves are still attached does cause some problems with dry leaves (particularly the petioles) being broken up and entering the combine bin as foreign matter.

*Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production*

4.**Stop regrowth.** Certain sesame varieties have a propensity for restarting growth and flowering after the main stem has stopped flowering. Regrowth usually occurs in areas where conditions are such that the plants have run out of moisture and/or fertility. If there is rain, some varieties will form branches at the bottom of the plant and these will flower and set capsules while the main stem and the older branches will not start flowering again (**Figures 11** and **12**). There are three types of regrowth: top (restarts at the tops of the main stems), middle (branches emerge from the middle of the main stem), and bottom (branches start in the axils of other branches or below the branches). There are varieties that show spontaneous branching whereby branches start in the middle of the capsule zone under capsules. However, this is not considered regrowth because spontaneous branches begin during flowering and stop flowering before the top of the main stem stops flowering. In regrowth,

**Figure 11.**

**218**

*Bottom regrowth (red arrow) below the lowest capsule (yellow arrow).*

*Middle regrowth (red arrow) in the middle of the capsule zone. Note: the sesame without regrowth is dry. Both of these are minor regrowth which has already stopped flowering. In some cases, there may be over 20 capsules on each branch.*

capsules on the original plant will dry down while it may take another 60 days for the regrowth capsules to mature and dry out. Since most of the yield is in the old growth, it can shatter while waiting for the regrowth to dry to be combined. Combining when the original plant is dry and the regrowth is green is similar to the weed situation in that it will introduce moisture into the combine bin. Using glyphosate as a harvest aid will kill the plant and stop the regrowth.

#### **Figure 13.**

*In many areas of the world, seed will germinate inside the green capsule when the temperatures are high. Even if only the top seeds germinate, the roots from the seedlings will trap the seeds below, preventing them from being harvested (Photo: D.R. Langham).*

5.**Stopping vivipary.** Under some conditions, there is vivipary in sesame—the seeds will germinate in the capsules (**Figure 13**). Not only are the germinated seeds lost, but the roots of the seedlings bind the rest of the seed and keep it in the capsule when combined.

grower sprayed glyphosate on a sesame crop with no leaves to eliminate volunteer sorghum and weeds within the crop and the glyphosate also killed the sesame without leaves. It was postulated that the capsules and stems absorbed the glyphosate and it translocated to the roots. In addition, the lack of leaves allowed the glyphosate to reach the lower stem and capsules. Subsequent testing was done at

*Effects of Harvest Aids on Sesame (*Sesamum indicum *L.) Drydown and Maturity*

With the above field observations, research was conducted to answer some questions. Previous experience, when sesame was swathed at maturity, had shown that if the sesame was cut earlier than PM, yield and quality of the seed would be reduced. Other experience had shown that even though sesame had been bred with improved non-dehiscence, weather could reduce the yield. Therefore, the objective of this research was to identify herbicides that may help promote desiccation of sesame and the effect of these herbicides on sesame development and also determine the optimum application timing to determine the amount of loss if the harvest

The weather was variable and it was very difficult to predict when PM would occur to schedule the sprayings. As mentioned previously, PM proceeds between 1 and 7 node pairs per week depending on the weather. The variability can be exacerbated when planting sesame under pivots. In several years of successive droughts, the moisture below 30 cm was depleted and the soil was very dry; therefore, no roots could penetrate the soil. Water in Texas can be scarce and when irrigating with an overhead irrigation system pivot, the minimum amount necessary is used. The results are roots that are often in the top 20–30 cm of soil. Irrigation is terminated when the crop stops flowering. If there is hot weather with low humidity, the sesame can go to drydown in less than 2 weeks instead of the normal 5–6 weeks. One harvest aid experiment in Uvalde was cancelled because the plants were in the late drydown stage at the predicted 1 week before PM. In another study, near Lorenzo, Texas, the crop was sprayed at least 2 weeks before PM because a cold

Field studies were conducted from 2006 through 2008 near Uvalde (29.468° N,

A randomized complete-block experimental design was used, and treatments were replicated three times. Treatments consisted of a factorial arrangement of four

herbicide treatments (carfentrazone-ethyl, diquat-dibromide, glufosinateammonium, and glyphosate) at two rates. A non-treated control was included for comparison. Herbicides included glyphosate (Durango® Herbicide,

99.7061° W) in the south Texas sesame growing region and near Lorenzo (33.6684° N, 101.5354° W) in the Texas High Plains sesame growing region to evaluate sesame response to harvest aids. Soil type at Uvalde was a Winterhaven silty clay loam (fine-silty, carbonatic, hyperthermic Fluventic Ustochrepts) with less than 1.0% organic matter and pH 7.8. Soil type at Lorenzo was an Amarillo sandy clay loam (fine-loamy, mixed, thermic Aridic Paleustalf) with 0.8% organic

front had delayed PM and the plants still had their leaves.

PM when the leaves had dropped naturally.

*DOI: http://dx.doi.org/10.5772/intechopen.91011*

aid was applied too early or too late.

**7. Field studies**

**7.1 Materials and methods**

*7.1.1 Research sites*

matter and pH 7.8.

**221**

*7.1.2 Herbicides and application*

Many growers have felt that the opening of the capsules allows water to enter and germinate the seed. The opposite occurs. Seeds in open capsules do not germinate because the moisture will evaporate out of the capsule before the seed can germinate. Vivipary occurs in closed capsules. It is believed that this is a dispersal mechanism to open the capsule and allow the seed to fall out. The exception in dry capsule is if the tip of the capsule has a minimum opening. Not only can there be vivipary, but there is also the danger of mold forming inside the dry capsules. When there is vivipary, the seedlings persist as the capsules continue to dry. Vivipary is controlled genetically through seed dormancy with some varieties having a greater propensity than others. Vivipary is rare in the USA because normally at harvest the night temperatures are below 15°C, the minimum germination temperature. Glyphosate will kill the sesame plants and stop vivipary.

6.**Prepare to plant a new crop**. In many areas of the USA, wheat and sesame are double cropped. The earlier the sesame is harvested, the earlier the wheat can be planted.
