Acc to weed science society of America, Herbicide resistance is the inherited ability of a plant to survive and reproduce following exposure to a dose of herbicide normally lethal to the wild type In a plant resistance may naturally occur or may get induced by such techniques as genetic enggineering or a selection of variant produced by tissue culture. It was altered response to a herbicide by a plant species which was earlier susceptible. Process of transferring gene from one living organisms to another to serve specific purposes is called Genetic engineering The crops produced by this process is called transgenic crops. If gene transfer into the crop is responsible for the herbicide resistant then crops are called THRC’s . HRC’s are genetically modified crops to which resistant to certain non-selective herbicides has been conferred. 1984, Commercially introduced in Canada through atrazine resistant canola variety. 1995, Monsanto introduced Roundup ready soybean. 1996, GM foods were first put on the market in USA. 71% of the of GM (genetically modified) plants were herbicide resistant. (Barber, 1999).   Cotton and rapeseed varieties are resistant to three herbicides- glyphosate, sulfonylurea and bromoxynil, in USA (DOWNEY 1999). There are 22 transgenic crops approved for commercial use in the world till March 2008. In the world, herbicide resistant corn, oilseed rape, soybean and cotton have been commercialized. Transgenic cotton crop is allowed for cultivation in India. Of the 29 countries that planted biotech crops in 2019, 19 countries were considered as biotech mega-countries, which grew at least 50,000 hectares . The USA remained as the top producer of biotech crops globally, which planted 71.5 million hectares & Brazil landed on the second spot, with 52.8 million hectares in 2019. Do u know where biotech crops are grown More than 30 countries have planted biotech crop since 1996. 2.7 billion ha of biotech crops planted since 1996 17 million small, resource-poor farmers and their families totaling greater than 65 million people benefited from biotech crop in 2019 see where they were grown in 2019 Usa is the largest producer of biotech crops in the world,planting37.6% of global biotech crop area 10 countries in latin america planted biotech crop in 2019 Biotech canolas adoption rate in canada reached 95% Brazil is the top developing country in the world planting biotech crops Spain is the leading country planting biotech maize in europe Malawi, euthopia and nigeria planted bt cotton for the first time in 2019 More than 6 million farmers in india planted 11.9 million hectare of bt-cotton.According to international service for the acquisition of agribiotech application In 2019 highest area and adoption rate was of biotech soyabean which was cultivated in 91.9 million heactares Biotech Maize was cultivated on 60.9 million hectares Biotech cotton was cultivated in 25.7 million ha Biotech canola in 10.1 million ha And other

1. Department of Agronomy
CSK HPKV, Palampur
Herbicide Resistant Crops : Boon or Bane
for Global Agriculture
Credit Seminar
Seminar In-charge :
Dr. Sandeep Manuja
Presenter : Shivalika
(A-2021-30-020)
( M.Sc. IInd year)

2. Contents
Introduction
History
Need of HRC’s
Development of HRC’s
Role & Scope of HRC’s
Future Thrust
Conclusion

3. Introduction
• Herbicide resistance is the inherited ability of a plant to survive and reproduce
following exposure to a dose of herbicide normally lethal to the wild type (WSSA).
• Process of transferring gene from one living organisms to another to serve specific
purposes is called Genetic engineering
• The crops produced by this process is called transgenic crops.
• If gene transfer into the crop is responsible for the herbicide resistant then crops are
called THRC’s .
• HRC’s are genetically modified crops to which resistant to certain non-selective
herbicides has been conferred.
3

4. History
 1984, Commercially introduced in Canada through atrazine resistant canola
variety.
 1995, Monsanto introduced Roundup ready soybean.
 1996, GM foods were first put on the market in USA.
 71% of the of GM (genetically modified) plants were herbicide resistant.
(Barber, 1999).
 Cotton and rapeseed varieties are resistant to three herbicides- glyphosate,
sulfonylurea and bromoxynil, in USA (DOWNEY 1999).
 There are 22 transgenic crops approved for commercial use in the world till
March 2008.
4

5.  In the world, herbicide resistant corn, oilseed rape, soybean and
cotton have been commercialized.
 Transgenic cotton crop is allowed for cultivation in India.
 Of the 29 countries that planted biotech crops in 2019, 19
countries were considered as biotech mega-countries, which grew
at least 50,000 hectares .
 The USA remained as the top producer of biotech crops globally,
which planted 71.5 million hectares & Brazil landed on the
second spot, with 52.8 million hectares in 2019.
5

6. 6

7. 7

8. Global Area of Biotech Crops in 2018 and 2019: by Country (million hectares)
Rank Country 2018 2019
1 USA 75 71.5
2 Brazil 51.3 52.8
3 Argentina 23.9 24
4 Canada 12.7 12.5
5 India 11.6 11.9
6 Paraguay 3.8 4.1
7 China 2.9 3.2
8 South Africa 2.7 2.7
9 Pakistan 2.8 2.5
10 Bolivia 1.3 1.4
Source: ISAAA, 2019 8

9. Potential yield loss due to weeds in different major crops of India
Crop Yield losses (%) Crop Yield losses (%)
Chickpea 10-50 Cotton 40-60
Pea 10-50 Pearlmillet 16-65
Fingermillet 50 Pigeonpea 20-30
Greengram 10-45 Potato 20-30
Groundnut 30-80 Rice 10-100
Horsegram 30 Sorghum 45-69
Jute 30-70 Soybean 10-100
Lentil 30-35 Sugarcane 25-50
Maize 30-40 Vegetables 30-40
Niger 20-30 Wheat 10-60
Rao et al. (2014) 9

10. Global Pesticides use (tonnes)
2744823.99 2748889.92
2678475.35
2653819.31
2661124.23
2016 2017 2018 2019 2020
10

11. 58634.43
63405.78
59669.93
61701.90 61701.90
2016 2017 2018 2019 2020
Pesticides use in India (tonnes)
11

12. Raj et al., 2021
12

13. Need of HRC’s ?
13
 To meet the demand of world population.
To reduce the weed damage.
To reduce the use of chemical herbicides in agronomic crops.
To decrease the phytotoxicity of herbicides to crops.
Expand herbicide spectrum.
Reduce cost of weeding.
To increase productivity.

14. 14
Herbicide
Selective
Herbicide
Non-Selective
Herbicide
Several crops have been modified to make them resistant to non-selective
herbicides. These genetically modified herbicide resistant crops harbor genes
that enables them to degrade the active component in the herbicide, making
the modified plant harmless to herbicide

15. Types of
resistance
Simple/
Natural
resistance
Cross
resistance
Multiple
resistance
Reverse
resistance
Negative
cross
resistance
Compound
resistance
15

16. Development of HRC’s
 Identification of useful gene
 The cloning of the gene into a suitable plasmid vector
 Delivery of the vector into plant cell
16

17. Development of Herbicide-Resistant Crops
Traditional selective plant breeding Biotechnological techniques
In vitro mutant
selection at the cell or
tissue level
Somatic
hybridization
Microspore(gametic)
and seed
mutagenesis
Plant Transformation
(transfer of cloned
genes into
susceptible plants)

18. 18

19. Mechanism of Glyphosate Action

20. Shikimic acid pathway
Glyphosate works by blocking the
plants ability to produce certain
proteins and it dirupts amino acid
synthesis. It blocks the shikimic acid
pathway.

21. Herbicide resistant crops or genes
21
Rao, 2018

22. 22
Rao, 2018

23. 23
Rao, 2018

24. Adoption rate of glyphosate-resistant crops in the United States
Source: USDA ERS (2009) 24

25. 25
Source : USDA, 2022

26. 26
Source : USDA, 2022

27. 27
Source : USDA, 2022

28. 28
Chinnusamy et al., 2014

29. WCE and grain yield in transgenic corn (mean of four seasons)
Chinnusamy et al., 2014 29

30. WCE and grain yield in transgenic corn hybrids (Kharif 2010)
Chinnusamy et al., 2014 30

31. Effect of glyphosate on amino acid and lignin content in GR soyabean
Zibiole et al.,2010

32. 32
Chinnusamy et al., 2014

33. Chinnusamy et al., 2014

34. Role of HRC’s
• To adopt minimum- or no-tillage systems.
• We can replaced previously toxic herbicides with glyphosate.
• In soybean and canola crops provides superior weed management.
• Manufacturers of other herbicides for cotton and soybean have
countered with reductions in prices for their products. (Nelson and
Bullock, 2003)
• Make crops resistant to most herbicide classes (Gressel, 2002).
• Glyphosate is rapidly degraded by soil microbes. (Duke et al., 2003).
• No effect of glyphosate on microflora of soils in Argentina at twice the
recommended rates of the herbicide. (Gomez and Sagardoy, 1985)
34

35. Scope of HRC’s in abroad
Corn :-
1. Over-the-top application of liberty (glufosinate) herbicide.
2. Post-emergence application of Roundup (glyphosate) and some other glyphosate-type
products directly to corn can provide broad spectrum annual and perennial weed
control .
Liberty link soybean:
• Allow over-the-top application of Liberty (glufosinate) herbicide. Roundup ready
soybean:
• It allows over-the-top application of Roundup Ultra (glyphosate) and some other
glyphosate containing products to soybean from cracking to flowering.
• The programme allows broad-spectrum control of many annual and perennial
grasses and broadleaf weeds in soybean crop.
35

36. Scope of HRC’s in India
The only genetically modified cash crop under commercial cultivation in India is
cotton.
Bt Cotton:
• Bt cotton is grown over 11.6 million hectares. Production of cotton is
increased from 308-550 kg/ha from 2002 – 2014.
GM-mustard:
• Dhara Mustard Hybrid-11 or DMH-11 is a GM variety of mustard developed
by the Delhi University’s Centre for Genetic Manipulation of Crop Plants.
• We can go for other crops after research like- Maize, Rice, Wheat, Soybean,
Tobacco etc.
36

38. Why Multinational companies more entrusted in
HRCs ?
1. Designing a new herbicide based on selectivity to each crop has
not been much successful in the past.
2.More economical than develop a new herbicide.
3.Take less time and more success in genetic engineering.
4.Marketing HRCs is more profit-driven since the concerned MNC
will sell seed and herbicide both.
5.Less risky and economical.
6.Marketing is less competitive because it remain exclusive business
of MNC, who develop it.
38

39. Advantages of HRCs towards Weed control
1. Encourage the safe use of non selective herbicide.
2. To control parasitic weeds selectively
3. To control weeds closely related to crops.
4. Reduce consumption of herbicide.
5. More simplicity and flexibility in the time of application.
6. Efficient weeds control provide higher yield.
7. Reduce total cultivation cost due to less traffic, less spraying- soybean brought down cost of
conventional herbicides from US $ 40 to $ 60 per acre to $ 20 to $ 30 per acre (Indian Rs. 2000
to 5000).
8. Useful where pre emergence application is not possible due to rain.
9. Other toxic and residual herbicide can be banned after HRCs adopted.
10. Use of herbicides that are more environment friendly- Glyphosate and Gluphosinate are absorb by
organic matter and decomposed readily.
39

40. Limitations of HRC’s
1. Adopting HRCs will leads to increase dependence on single herbicide or
family.
2. It influence the genetic purity of crops.
3. May cause gene pollution and chance to develop “super weeds”.
4. Crop seed or propagules left in the field results resistant volunteer crops.
5. Safety of GMC food is also great concern among the people.
6. Contamination of food.
7. Long time use cause limit the bio-diversity.
8. Continuous use of same herbicide may develop resistant in weeds
9. Abandonment of IWM in course of time.
10. Possible shift in weed spp./insect pest.
40

41. Future Thrust
 Without public opposition, availability of current available and future HRC’s
would eventually result in almost universal use of the products in all major
crops.
 Growth of the adoption of HRC’s will, however, depend on more than their
value to the farmer.
 In a world economy, the rejections of transgenic crops by the Europian public
could have a profound influence on their utilization in exporting countries
such as United States, even if there is little opposition to their use where they
are grown. Public opinion where they are now accepted could change.
 Whether HRC use increases or decreases is unlikely to significantly influence
reliance on herbicides for weed management in major crops.
 New technologies such as precision agriculture and decision aid programs for
weed management will, however, reduce both the volume of herbicides used
and their environmental impact.
41

42. Conclusion
 Herbicide resistant crops have a great potential in the simplification of weed
management.
 Handled judiciously, these crops may beneficial by allowing effective, efficient and
later weed control, enabling no-till systems, reducing erosion and cost of cultivation.
 As environment point of view, it reduces pollution, energy used during cultivation,
global warming and ozone depletion.
 However, it must be emphasised that the risk from HRC’s should be carefully
evaluated prior to releasing the HRC into a cropping system.
 For long-term benefits of HRC, and avoiding risks, these must be used as component
of IWM and not in isolation, and overuse, abuse or misuse should be avoided.
42
Currently, there is no herbicide resistant biotech crop that is permitted by the national
government to grow. The glyphosate-resistant cotton has not received the approval
Genetic Engineering Approval Committee (GEAC) of Government of India.

44. Farmer problems with herbicide-resistant crops
• HRCs and conventional cultivars of crops cannot be
visually distinguished from each other.
• Accumulation of a seed-bank of canola seed with
single and multiple herbicide resistance traits is a
potential long term problem for producers.
• Gene flow from transgenic to non-transgenic cultivars
of the same crop.
• Preserving non-transgenic canola identity .

45. Risks
• Problems with grain contamination.
• Segregation and introgression of herbicide-
resistant traits.
• Marketplace acceptance.
• Increased reliance on herbicides for weed
control.