**9. Discussion**

Since the 1950s study by M. Kinman (personal communication, 1982), there have been no studies to try to define PM. Those studies were based on cultivars that had dry, open capsules at the bottom of the plant while the top was not mature. His criterion was to find the point of maximum yield knowing there is an offset of the weight gained by more seed fill versus the weight loss by shattering. Current cultivars do not have dry, open capsules until after the tops of the plants have completed seed fill. Testing should show the amount of yield lost by spraying 1, 2, 3, and 4 weeks ahead of PM. There is no credible way to show the loss by spraying 1, 2, 3, and 4 weeks after PM because the weather cannot be controlled. Rain, fog, dews, temperature, relative humidity, and wind affect the amount of shattering and lodging. In doing this type of study it is important to test all the phenotypes. Sesame phenotypes can be classified by the amount of branching (no branching, few branches, or many branches) and the number of capsules per leaf axil (single or triple capsule). Over 30 lines were segmented into lower main stem, middle main stem, upper main stem, lower branches, and upper branches with the percentage of seed weight in each of the segments depending on phenotype (**Table 4**). The branches complete flowering and seed fill before the main stem [18]. If one phenotype is chosen for the study and the phenotype does not have branches, there will


*1 Abbreviations: BR, branches; LMS, lower main stem; MMS, middle main stem, UMS, upper middle stem; MS, main stem; LBR, lower branches; UBR, upper branches.*

#### **Table 4.**

*Percentage of seed weight in segments of the plants.*

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


*a There is an exception with herbicide tolerant weeds. There are also some weeds that are killed more effectively by one herbicide, e.g.* Ipomoea *spp. with carfentrazone-ethyl.*

#### **Table 5.**

In 2007 at the PRE PM stage, diquat-dibromide at 0.56 kg ha<sup>1</sup> and both rates of glufosinate-ammonium produced yields that were greater than the untreated check (**Table 3**). At the PM stage, both diquat-dibromide and glufosinate-ammonium increased yield over the untreated check while glyphosate was not different than the untreated check. At the POST PM stage, only diquat-dibromide at 0.56 kg ha<sup>1</sup>

In 2008 at any sesame development stage, none of the herbicides improved yields over the untreated check. However, at the POST PM stage, diquat-dibromide

In 2007 or 2008 no differences in sesame yield was noted between the untreated check and any herbicide treatment (**Table 3**). In 2008, glyphosate at 0.84 kg ae ha<sup>1</sup> applied POST PM did result in greater yield than glyphosate at either rate applied

Since the 1950s study by M. Kinman (personal communication, 1982), there have been no studies to try to define PM. Those studies were based on cultivars that had dry, open capsules at the bottom of the plant while the top was not mature. His criterion was to find the point of maximum yield knowing there is an offset of the weight gained by more seed fill versus the weight loss by shattering. Current cultivars do not have dry, open capsules until after the tops of the plants have completed seed fill. Testing should show the amount of yield lost by spraying 1, 2, 3, and 4 weeks ahead of PM. There is no credible way to show the loss by spraying 1, 2, 3, and 4 weeks after PM because the weather cannot be controlled. Rain, fog, dews, temperature, relative humidity, and wind affect the amount of shattering and lodging. In doing this type of study it is important to test all the phenotypes. Sesame phenotypes can be classified by the amount of branching (no branching, few branches, or many branches) and the number of capsules per leaf axil (single or triple capsule). Over 30 lines were segmented into lower main stem, middle main stem, upper main stem, lower branches, and upper branches with the percentage of seed weight in each of the segments depending on phenotype (**Table 4**). The branches complete flowering and seed fill before the main stem [18]. If one phenotype is chosen for the study and the phenotype does not have branches, there will

**Branch Caps LMS<sup>1</sup> MMS UMS MS LBR UBR BR** %

Few 1 27.1 28.8 23.7 79.6 9.9 10.5 20.4 Many 1 22.4 23.5 17.7 63.6 15.9 20.5 36.4

Few 3 19.1 32.5 26.9 78.5 10.6 10.9 21.5

*Abbreviations: BR, branches; LMS, lower main stem; MMS, middle main stem, UMS, upper middle stem;*

None 1 31.2 37.1 31.7 100.0

None 3 25.5 41.8 32.7 100.0

*MS, main stem; LBR, lower branches; UBR, upper branches.*

*Percentage of seed weight in segments of the plants.*

at 0.56 kg ha<sup>1</sup> improved sesame yield 29–34% over diquat-dibromide at

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

increased yield over the untreated check.

*8.2.2 Uvalde*

**9. Discussion**

*1*

**Table 4.**

**226**

0.28 kg ha<sup>1</sup> and glyphosate at 0.84 kg ha<sup>1</sup> (**Table 3**).

PRE PM or diquat-dibromide at both rates applied POST PM.

*Performance of herbicides on sesame harvest aids requirements.*

probably be a shorter cutting window before there is substantial yield loss by cutting early as opposed to a phenotype with many branches.

These studies led to the US EPA approval of glyphosate as a harvest aid. As a result, glyphosate has been used as a harvest aid on hundreds of thousands of hectares in the last 10 years. Past experience plus these experiments provide an idea of how these herbicides satisfy the requirements for harvest aids for sesame (**Table 5**).

#### **10. Conclusions**

The use of herbicides in sesame did accelerate drydown although this did not always result in an increase in yield over the untreated check. However, there was no weather event such as rain, fog, dews, or strong winds during the experiment which would have an impact on the results. Diquat-dibromide and glufosinateammonium dried the sesame faster than glyphosate and carfentrazone-ethyl.

With all herbicides, the higher rate dried the sesame down faster.

Efforts should be continued to try to persuade manufacturers to support for registration of diquat-dibromide and glufosinate-ammonium. Even though carfentrazone-ethyl is not as effective as glyphosate, with the present legal battles with glyphosate as a carcinogen, efforts should be made to register carfentrazoneethyl. Stopping regrowth and vivipary is not an experiment that can be set up because they do not occur in most of the fields or nurseries. However, when a field is found with regrowth and/or vivipary, glufosinate-ammonium, carfentrazoneethyl, and diquat-dibromide should be tested and glyphosate should be added for comparison purposes.

#### **Acknowledgements**

Sesaco Corporation provided funding for this research.

#### **Conflict of interest**

There is no conflict of interest with any of the authors.

**References**

251-258

2018]

**229**

[1] Griffin JL, Boudreaux JM, Miller DK. Herbicides as harvest aids. Weed Technology. 2010;**58**:355-358

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

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

[8] Johnson B, Nice G, Bauman T. Harvest aid herbicides for winter wheat. Purdue Weed Science. 2004. Available from: ag.purdue.edu/btny/weedscience/ documents/harwheat03.pdf [Accessed:

[9] Jordan D. Peanut weed management. In: Peanut Information Handbook. University of North Carolina Extension; 2018. Available from: content.ces.ncsu. edu/peanut-information/peanut-weedmanagement [Accessed: 07 October 2019]

[10] Chaudhari S, Jordan D, Jennings K. Peanut (*Arachis hypogaea* L.) response to carfentrazone-ethyl and pyraflufenethyl applied close to harvest. Peanut

Baughman TA. Peanut variety response to postemergence applications of carfentrazone-ethyl and pyraflufenethyl. Crop Protection. 2010;**29**:

[12] Hardke J. Harvest Aids on Hybrid Rice. University of Arkansas Research and/Extension; 2018. Available from: http://www.arkansas-crops.com/2018/ 09/06/harvest-aids-hybrid/ [Accessed:

[13] Anonymous. Harvest management. In: Canola Encyclopedia. 2018. Available from: https://www.canolacouncil.org/ canola-encyclopedia/managing-harvest/ harvest-management/ [Accessed: 21

Barber LT, Raper TB. Mid-South Cotton Defoliation Guide. Mississippi State University Extension. University of Arkansas Extension and University of Tennessee Extension; 2016. Available from: https://extension.tennessee.edu/ publications/Documents/W376.pdf [Accessed: 23 September 2018]

07 October 2019]

Science. 2017;**44**:47-52

1034-1038

25 September 2018]

September 2018]

[14] Dodds DM, Reynolds DB,

[11] Grichar WJ, Dotray PA,

[2] Boudreaux JM, Griffin JL, Etheredge

[3] Philbrook BD, Oplinger ES. Soybean field losses as influenced by harvest delays. Agronomy Journal. 1989;**81**:

Stephenson DO. Utilizing Harvest Aids in Grain Sorghum. Louisiana State University Ag Center; 2017. Available from: http://www.lsuagcenter.com/ profiles/aiverson/articles/page

1503673878799 [Accessed: 22 September

[5] Trostle C, McGinty J. Texas Grain Sorghum Weed Control & Harvest Desiccation Guide. Texas AgriLife Extension; 2016. Available from: texassorghum.org/2016-texasgrain-sorghum-weed-controlharvest-desiccation-guide.html [Accessed: 08 October 2019]

[6] Bean B. Sorghum and the use of a harvest-aid product. In: United Sorghum Checkoff Program. 2017. Available from: http://www.sorgh umcheckoff.com/news-and-media/ newsroom/2017/09/15/sorghumand-the-use-of-a-harvest-aid-product/

[Accessed: 22 September 2018]

[7] Armstrong J. Harvest aid weed control in wheat. In: Production Technology Report. PT 2009-2 21(2). Oklahoma State University Extension. 2009. Available from: http://weedscie nce.okstate.edu/4-h/small-grains/ PT2009-2-%20Harvest%20Aid% 20Weed%20Control%20in%20Wheat. pdf/ [Accessed: 23 September 2018]

LM Jr. Utility of harvest aids in indeterminate and determinate soybeans. Proceedings of the Southern Weed Science Society. 2007;**60**:91

[4] Fromme D, Price OPIII,
