Maize is called as “King of cereals” because of its high productivity and adaptability.

It is the 4th most important crop next to rice, wheat and sorghum.

Area, production and productivity of maize in 2007.

This year, maize production has been severely affected due to insufficient rainfall, which adversely influenced the epidemic of stem borers. (source: Dr.C.P.Mallapur,entomologist)

Area Production Productivity

World 139 (mha) 590 (mt) 4229 (Kg/ha)

India 7.32 (mha) 14.93 (mt) 19.04(q/ha)

Karnataka 9.3 (lakh ha) 16.2 (lt) 29.5 (q/ha)

Source: Science & technology, Deccan herald, Tuesday, August 5,2008.

Maize Area, Yield and Production for Top 10 Maize Countries 2006.

Sl.noCountry

Harvested Hectares(Millions)

YieldMT/Hectare

Production(Millions MT)

1 USA 28.5 8 228.7

2 China 24.5 5.1 124.2

3 Brazil 11.8 3 35.5

4 Mexico 8 2.4 19

5 India 6.2 1.9 12

6 Nigeria 4.2 1.3 5.4

7 South Africa 3.3 2.7 9.1

8 Indonesia 3.3 2.8 9.3

9 Romania 2.9 2.9 8.510 Philippines 2.4 1.8 4.3

Distribution of World Maize Production

Source: CIMMYT, Mexico

Stem borers causes 80% of losses in maize. It is a polyphagous pest.

Global level loss due to borers - $ 5.7 billion annually Insecticides used - $550 million annually.

In US 1$ billion per annum – control + losses.

These borers belong to the order: Lepidoptera family : Pyralidae

There are different species of stem borers are their which causes damage to the crop.

Sl.no Common Name Scientific Name Affected RegionsI Tropical stem borers 1 Spotted stem borer Chilo Partellus Asia, East Africa2 Oriental corn borer (Asian corn borer) Ostrinia furnacalis Asia3 Lesser cornstalk borer Elasmopalpus lignosellus Americas4 Pink stem borer Sesamia cretica Africa5 African pink stem borer Sesamia calamistis Africa6 African maize stalk borer Busseola fusca Africa7 African sugarcane borer Eldana saccharina Africa8 Asiatic rice borer Chilo suppresalis Asia9 Asiatic pink stem borer Sesamia inferens Asia

10 Sugarcane borer Diatraea saccharalis AmericasII Subtropical stem borers 1 European maize borer Ostrinia nubilalis North Africa, Mideast2 Lesser corn borer Elasmopalpus lignosellus Americas3 Oriental corn borer (Asian corn borer) Ostrinia furnacalis Asia4 Spotted stem borer Chilo partellus Africa5 African maize stalk borer Busseola fusca Africa6 Sugarcane borer Eldana saccharina Africa7 Sugarcane borer Diatraea saccharalis Americas8 Southwestern corn borer Diatraea grandiosella AmericasIII Temperate stem borers 1 Southwestern corn borer Diatraea grandiosella North America2 Sugarcane borer Diatraea saccharalis Southern Cone, S. America3 Lesser corn stalk borer Elasmopalpus lignosellus Southern Cone, South America4 Oriental corn borer Ostrinia furnacalis East Asia5 European corn borer Ostrinia nubilalis Europe, North America

Lepidopteran pest species of the world

Maize Borer Map of the World .

Source: CIMMYT, Mexico

Life cycle of stem borer

Sites of damage caused by pest in maize

Stem borers

Damage caused by borers

Symptoms of pest attack in maize

Control of stem borers Cultural methods

Biological control.

Application of Carbaryl 4% G or Endosulfan 8% G @ 7.5 – 15 Kg/ha into the leaf whorls.

Spraying of endosulfan 35 EC @ 2ml/liter.

Bt maize

History of Bt Bt was Ist isolated by Japanese biologist, Ishiwatari when he was

investigating the cause of the Sotto disease (sudden collapse disease) in silkworms.

In 1915, Berliner reported the existance of a crystal within Bt, but activity was not discovered at that time.

1920, farmers started using Bt as a pesticides.

But the Bt products such as spray are rapidly washed away by rain and degrade under the sun’s UV rays.

in 1956,Hannay, James and Angus found that the main insecticidal activity was due to crystal. With this discovery came interest in the crystal structure, biochemistry and general mode of action of Bt.

In US, Bt was commercially started in 1958.

In 1961, Bt was registered as a pesticide in EPA (Environmental Protection Agency) .

Until 1977, only 13 Bt strains had been described, which are toxic to lepidopteron larvae. By the end of 1983, new strain was discovered which was toxic to species of coleopteran (beetles).

Today, there are thousands of strains of Bt. Many of them have genes that encode unique toxic crystals n their DNA.

The Ist Genetically engineered plant, Corn was registered with the EPA in 1995.

Presently available GM Crops like Soybean, Cotton, Papaya, Tomato, Potato, Okra, Brinjal.

Bt Maize Events that have been Approved for Commercial Planting

Event Gene Year approved Country Product Name CompanyMON 810

cry1Ab

1996 USA Yield Gard®Corn borer

Monsanto

1997 Canada1997 South Africa1998 Argentina1998 EU2000 Bulgaria2002 Philippines2003 Uruguay

Bt 11

cry1Ab

1996 USA Yield Gard®

Syngenta

1996 Canada1996 Japan2001 Argentina

176

cry1Ab

1995 USA Knockout®

Syngenta

1996 Canada1997 EU1998 Argentina

MON 863

cry3Bb1

2003 USA Yieldgard®Rootworm

Monsanto 2003 Canada

TC 1507

cry1Fa2

2001 USA Herculex® 1

Pioneer Hi-BredMycogen Seeds -

Dow Agro Sci.2002 Canada 2002 Japan

History of Bt Corn

Outbreak in Minnesota in 1995 cost of 285 million $

Ist Hybrid is released in 1996 by Monsanto ,Yield Gard

Bt (Bacillus thuringiensis)

Gram +ve bacteria cry gene produces protein called delta-endotoxin which is active against a specific species

of target pest. Harmless to human, birds, animals and

other non target organisms.

Genotype

pore-forming domain I

receptor binding domains II

crystals are made up of pore-forming toxins

Bacillus thuringiensis : produces proteins

that kill insectsThe proteins are called “Cry”, because they occur in crystals

sporulation induces synthesis of crystals

Domain III which protect the endotoxin

Physiological mechanism of Cry toxin action

Lepidoptera

Coleoptera

Diptera

Cry Toxin Specificity

Crickmore et al. 1998

Nematoda

The Expression of a Synthetic cry1a(b) Gene in Transgenic Maize Confers Resistance to European Corn Borer.

Insect resistance maize:Recent advance and utilization (1994),CIMMYT. Estruch.J.J, Carozzi.N.B, Desai.N, Warren.G.W, Duck.N.B and Koziel.M.G , CIBA Agricultural Biotechnology, USA.

Material and method: Vector used are derivatives of pUC 18 or pUC 19. Contain truncated- synthetic version of the cry1A(b) genes from Bt

var.kurstaki. Placed under the control of either the CaMV 35S promoter or

tissue-specific prompters.

CaMV 35S Synthetic cry1A (b) [648aa]

Maize PEPC Synthetic cry1A (b) [648aa]

Maize pollen Synthetic cry1A (b) [648aa]

Maize pith Synthetic cry1A (b) [648aa]

Event 171

Event 176

Immature embryos were excised 2 weeks after pollination & planted in 2DG4 + 5 mg/l chloramben.

Plasmid DNA was deposited on microprojectiles at rate of 6mg of DNA /50 ml of microcarrier.

Delivery of the microprojectiles is performed using PDS-1000He Biolistic gun with rupture disks of 1550 psi.

After bombardment, embryos are kept for 1 day in the dark at 25 °c.

Transformed to callus induction medium, 3mg/l of phosphinothricin (PPT)

Embryogenic callus was transferred to 2DG4 with 0.5mg/l of 2,4-D.

12 weeks later, tissue transferred to MS medium containing 3% sucrose & harmones.

Isolate plant cells

Grow

undifferentiated callus

Transform cells

Select cells

Redifferentiate callus

Grow transgenic plant

Cont……..

Transformed plants were identified by PCR for sequences in the promoters and

synthetic cry1A(b) gene.

Positive plants were moved to greenhouse for additional tests and crosses with various inbreeds.

Quantitative determination of the levels of cry1A (b) protein were performed by ELISA.

Results

Increasing the GC content of Bt insecticidal protein genes leads to better expression in plants.

The insect control group at CIBA decided to make a synthetic version of the cry1A(b) gene by increasing GC content from 38% in native gene to 65%.

Transgenic maize for the cry1A (b) gene under

PEPC specific promoter – 1000 ng /mg of crude protein. Pollen specific promoter – 400 ng / mg of crude protein

Pith specific promoter- 35 ng/mg of crude protein.

Not detected in the kernels.

The presence of cry1A(b) protein in pollen is important because it is the main diet during the 1st and 2nd instars of the ECB.

Screening Cry Proteins By Bt Maize Leaves For Activity Against Kenyan Maize Stem Borers.

S.Mugo, D.Bergvinson, D.Hoisington, S.McLean, C.Taracha, B.Odhiambo, J.songa, I.Ngatia and M.Gethi. Seventh Eastern And Southern African Regional Maize Conference, 11th-15th feb,2001

Materials and methodsMaize leaves: The Bt maize tissues that were introduced from the following 6

transgenic lines: 1. leaves from plants containing Event 176 [cry1Ab driven by the maize pollen

specific promoter and maize PEPC promoter (plasmid pCIB4431) co-tansformed with the bar gene driven by the CaMV 35s promoter (plasmid pCIB3064)].

2. Leaves from 5th generation plants containing Event 5207 [cry1Ac driven by maize ubiqitin promoter (plasmid pU02) co-transformation with the bar gene driven by the enhanced CaMV 35s promoter (plasmid pHO620)].

Cont….

3. Leaves from 5th generation plants containing Event 5601 [cry1B driven by the rice actin promoter and bar driven by the CaMV 35S promoter (plasmid pCIRAD3)].

4. Leaves from 2nd generation plants containing Event 1835 [cry1B driven by the maize ubiquitin promoter and bar driven by the CaMV 35S promoter (plasmid pCIRAD4) co-transformed with the bar/gus genes driven by the maize ubiquitin promoter (plasmid pACH25)].

5. Leaves from 2nd generation plants containing Event 7 [cry1B-1Ab driven by the rice actin promoter and bar driven by the CaMV 35S promoter (plasmid pCIRAD 7)].

6. Leaves from 2nd generation plants containing Event 602 [cry1E driven by the rice actin promoter and bar driven by the CaMV 35S promoter (plasmid pCIRAD 58)].

Backcross GM plant into high yield crops

GM plant = yyGG

High yield plant =

YYgg

YYgg x yyGG YyGg

YYgg x YyGg YYgGYygGYYggYygg

YYgG x YYgG YYgGYYggYYGgYYGG

Two farmers stand among rows of non-Bt corn, which has suffered insect damage and on either side are rows of Bt corn.

“Management” means that a certain acreage must be set aside for the non-GM crop so that the insects will thrive there.

This will reduce the selection pressure and the occasional mutant that evolves will find a non-mutant mate.

This greatly delays the emergence of resistance.

Bt crop Non Bt crop

Concerns Concerns Of Insect resistance

Infection of corn by Fusarium (ear rot) and Aspergillus (kernal rot) is more common when corn is damaged by insects. Fusarium produces fumonisin and Aspergillus produce Aflatoxins,a potent mycotoxin.

FDA “Guidance for Industry” for fumonisin levels of 2 to 4 µg/g in human food and animal feeds.

Fatal to animals & carcinogens in humans.

Insecticides

Difficult to control.

Residues for only short period.

Useful when larvae have just hatched or migrate to neighboring plants.

Proper timing of spray is crucial for success.

Harmful to other non target organism.

Bt maize

Easy to control.

Produces crystal like protein that selectively kill specific group of insects.

Effective to all stages of pest.

Depending upon the gene inserted the protein cry1Ab, cry1Ac, cry1B, cry9c are produced.

Harmless to other non target organism.

Pros and Cons of genetically engineering Pros and Cons of genetically engineering crops with Btcrops with Bt

Pros:1. Stable during several

years of storage2. Resistance of the

crystals to inactivation by UV light

3. Reduction in insecticide sprays (labor and chemical costs).

4. Increased activity of natural enemies.

5. Biological control can be used on secondary pests

Cons:1. Specificity of strains;

activity against some pests, but poor activity against others

2. Takes longer to kill pests, perceived as less effective

3. You still need to control the “secondary” pests

4. Cost of transgenics5. Development of

resistance because of persistent exposure