breeding for insect resistance hessian fly in wheat a case study stephen harrison fangneng huang...

Breeding for Insect ResistanceHESSIAN FLY IN WHEATHESSIAN FLY IN WHEAT

A case studyA case study

Stephen HarrisonStephen HarrisonFangneng HuangFangneng HuangRogers LeonardRogers Leonard

Acknowledgements: David Buntin - Dept. of Entomology – University of Georgia – Griffin CampusJohn Van Duyn - NC State University Randy Weisz – NC State

Ben Edge – Clemson University

Larvae

Puparia (flaxseed)

Hessian fly damage looks different, depending on when the wheat was infested

sometimes a wide leaf blade is a symptom. Often the wide blade has a blue-green hue.

Fly damaged plants and/or tillers

Adults

Hessian fly Mayetiola destructor

•There are 4-6 generations each year.

•A generation takes about 35 days at 75 º F, longer at cooler temperatures.

•Development occurs between 40-80 º F

1 2-3 3-4

HHessian fly Yield essian fly Yield LossLoss

Dec 2008 – Maringouin, LA

Seedling and early tiller stage:• One larva completely stunts and kills tiller /plant• Can have tremendous stand loss (> 75%)• Plants just mysteriously die

Hessian fly yield loss in winter wheatHessian fly yield loss in winter wheat

Jointing / Heading / grain fill stage:Jointing / Heading / grain fill stage:

Multiple larva per stems at jointsMultiple larva per stems at joints Stunts stemStunts stem Weaken stem cause lodging.Weaken stem cause lodging. Reduces grain filling / test weight.Reduces grain filling / test weight.

Ryegrass /winter wheat are common for food plots in southern “green fields”.

Inoculum Sources

• minimum tillage soybeans following wheat• early-planted wheat as pasture and foodplots• wheat straw for erosion control on roadbeds• volunteer wheat plants that emerge early• neighboring fields

• oats are not a host• rye and triticale are usually resistant

Winter Wheat Acreage and Losses to Winter Wheat Acreage and Losses to Hessian Fly in Georgia (1972-2007)Hessian Fly in Georgia (1972-2007)

0

200

400

600

800

1000

1200

1400

1600

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

Ha

rve

ste

d a

cre

s (

x1

00

0).

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

$ L

os

se

s

Acreage $ Losses

Hessian fly outbreak years

$28M

Effect of Spring Tillage on Hessian Effect of Spring Tillage on Hessian Fly Emergence from Wheat StubbleFly Emergence from Wheat Stubble

(From Chapin et al. 1992. J. Entomol. Sci. 27:293)(From Chapin et al. 1992. J. Entomol. Sci. 27:293)

0

5

10

15

20

25

30

Hes

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flie

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er t

rap

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No-till Burn Disk Burn &Disk

Plow

aab

bc

c

d

The best disease or insect control method is a resistant variety

There are numerous Hessian Fly biotypes, each with a different set of resistance genes it is able to overcome.

Numerous plant resistance genes have been identified for Hessian flies. As they are deployed, new biotypes emerge.

It is important to know what biotypes are present in order to choose the right Hessian fly "resistant" variety

Some varieties have resistance mechanisms that are not detected in seedling assays but work well in the field as adult plants.

• Delayed planting date and seed-applied insecticides may work well with this type of resistance.

Hessian Fly Biotype Hessian Fly Biotype Composition in Southern Composition in Southern

Georgia (1986-2000) Georgia (1986-2000)

0%10%20%30%40%50%60%70%80%90%

100%

1986 1989 1991 1996 2000 2008

E

G

M

O

L

Other

Sources: R. Ratcliffe et al., USDA-ARS, Purdue Univ.

?

Gene GP A B C D E F G H I J K L M N OH1H2 R R R R R RH3 R R S R S S R S R R S R S S R SH5 R R R R R R R R S ? S S S S S SH6 R R R S S R S S R R R S S R S SH7H8 R S S S S R R R R ? S S S R R RH9 R R R S R R RH9H10 R R R R R R RH10 R R R RH11 R R RH12 R R R RH13 R R R R R R R R R R R R R R RH14H15 R R R RH17 R R R RH18(Marq) R R R R R RH19 R R R RH21(Hamlet) R R R R R R R R R R R R R R R RH22 R R R R R R R R R R R R R R R RH23 R R R R R R R R R R R R R R R RH24 R R R R R R R R R R R R R R R RH25 R R R R R R R R R R R R R R R RH26 R R R R R R R R R R R R R R R RH28H31Kawvale

Biotype

Adult Plant? Tolerance?

Hessian fly resistance chart

Non-efective genes??H gene Source R-S % R R-S % R R-S % R R-S % R

No gene Newton 0-23 0 0-23 0 0-21 0 0-22 0H3 Monon 0-21 0 0-23 0 0-19 0 0-22 0H5 Magnum 0-19 0 0-22 0 2-18 10 0-22 0H6 Caldwell 2-18 10 0-21 0 10-10 50 5-16 24H7H8 Seneca 0-24 0 1-22 4 0-15 0 0-16 0H9 Iris 17-3 85 23-1 96 12-7 63 21-3 88H10 J oy 8-9 47 15-8 65 12-7 60 19-6 76H11 Karen 6-9 40 9-10 47 2-18 10 1-19 5H12 Lola 15-1 94 12-0 100 14-2 88 19-1 95H13 Molly 21-0 100 22-1 96 23-0 100 18-2 90H14 921676A3-5 12-6 67 9-10 47 6-15 29 3-18 14H16 921682A4-6 0-20 0 14-6 70 10-15 40 13-9 54H17 921680D1-7 16-0 100 20-0 100 10-3 77 7-8 47H18 Marquillo 17-0 100 11-0 100 11-6 65 14-4 78H21 Hamlet 20-0 100 19-0 100 21-1 95 22-0 100H22 KS85WGRC01 13-2 87 16-1 94 18-6 75 13-1 93H23 KS89WGRC03 6-2 75 5-2 71 5-1 83 2-5 29H24 KS89WGRC6 8-0 100 10-0 100 6-0 100 10-0 100H25 PI 592732 19-0 100 20-0 100 21-0 100 18-0 100H26 KS92WGRC26 11-0 100 8-0 100 7-0 100 12-0 100H31 P921696A1-15-2-1 16-0 100 8-11 42 18-3 86 12-7 63H32 Synthetic 11-3 79 17-2 89 14-7 67 16-1 94

red indicates most effective genes against these pops.green indicates least effective genes

Iberville Iberville Pointee PointeeLewis Hurdle J arreau Rummler

2008 Hessian Fly Biotypes in Louisiana

CHEM VAR STD DT HFNONE AGS 2026 0.0 0.0 0.0NONE DYNA-GRO OGLETHORPE 0.0 0.3 0.2NONE AGS 2060 0.3 0.3 0.3NONE AGS 2055 2.3 1.7 2.0NONE PIONEER 26R61 4.3 3.0 3.7NONE APCK 5E35 4.7 3.7 4.2NONE MAGNOLIA 5.3 3.7 4.5NONE TERRAL LA482 5.7 5.3 5.5NONE USG 3555 6.0 5.7 5.8NONE DELTA KING DK9108 6.3 5.7 6.0NONE USG 3592 6.7 6.0 6.3NONE AGS 2020 6.7 6.3 6.5NONE PIONEER 26R87 6.7 6.7 6.7NONE COKER 9700 7.0 6.7 6.8NONE USG 3295 7.0 6.7 6.8NONE TERRAL LA841 7.0 7.0 7.0NONE AGS 2031 7.3 7.3 7.3NONE Coker 9553 7.7 7.7 7.7

Mean 4.9 4.5 4.7LSD10% 1.3 1.3 1.2CV% 19.0 22.0 19.0

HESSIAN FLY DATA with no insectcide seed treatment. Dec 17, 2008. Maringouin, LA. S. Harrison.

STD: 0 = no stand loss; 5 = moderate stand loss; 9 = complete stand lossDT: 0 = no dead/dying tillers; 5 = moderate; 9 = complete/100%HF: Hessian Fly Index = average of STD & DT: 0 = completely resistant; 9 = completely susceptible

Insecticides for Hessian FlyInsecticides for Hessian Fly Gaucho 600Gaucho 600

0.8 to 2.4 fl. oz. / 100 lb0.8 to 2.4 fl. oz. / 100 lb Gaucho XTGaucho XT

3.4 oz/100 lbs seed3.4 oz/100 lbs seed Raxil & Apron fungicidesRaxil & Apron fungicides Rate too low for HFRate too low for HF

Gaucho XT + Gaucho 600 Gaucho XT + Gaucho 600 @ 1 oz/100 lb seed@ 1 oz/100 lb seed

Commercial seed treaterCommercial seed treater Seed conditioner, dealerSeed conditioner, dealer

Cruiser 5FS (Wheat-Pak)Cruiser 5FS (Wheat-Pak) 1 oz/100 lb seed1 oz/100 lb seed Contains 3 fungicidesContains 3 fungicides Rate too low for HFRate too low for HF Max. 1.33 oz/100 lb seedMax. 1.33 oz/100 lb seed

Karate Z (1.92 oz/A) Karate Z (1.92 oz/A) @ 2-4 leaf stage. @ 2-4 leaf stage. @ full tiller (early to mid @ full tiller (early to mid

March)March) Suppression; Timing Suppression; Timing

difficultdifficult

VAR Cruiser None

USG 3555 0.00 0.63AGS 2060 0.00 0.75PIONEER 26R61 3.50 4.50PIONEER 26R87 6.25 5.75TERRAL LA821 6.13 6.13TERRAL LA841 5.75 6.50

MEAN 3.61 4.04

Significant at 5%

HF: Hessian Fly Index = 0 = no damage; 9 = severe damage

HESSIAN FLY DATA: Seed Treatment Comparison. Dec 17, 2008. Maringouin, LA.

Cruiser Significantly reduced Hessian Fly damage, but:• the level of control provided was not adequate• very severe damage still occurred on susceptible varieties.

Hessian Fly Management Hessian Fly Management TacticsTactics

Rotate wheat if possible. Rotate wheat if possible. Control volunteer wheat. Control volunteer wheat. Do not use susceptible wheat as cover Do not use susceptible wheat as cover

crops/wildlife plantings.crops/wildlife plantings.Conventional tillage (fall and spring).Conventional tillage (fall and spring).Plant at recommended times.Plant at recommended times.Variety selection.Variety selection.

Plant resistant varieties (if possible).Plant resistant varieties (if possible).Plant susceptible varieties ‘only’ in new fields.Plant susceptible varieties ‘only’ in new fields.

Insecticides use strategiesInsecticides use strategiesSeed treatments Seed treatments Lambda cyhalothrin - scouting for late winter Lambda cyhalothrin - scouting for late winter

suppression. suppression.

Hessian Fly – 2009 - LAHessian Fly – 2009 - LA

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Breeding for Resistance to Breeding for Resistance to InsectsInsects

S.A. HarrisonS.A. Harrison

Spring 2007Spring 2007

ImmunityImmunity

A variety is not consumed or injured by an A variety is not consumed or injured by an insect that is known to attack other insect that is known to attack other varieties of the same species.varieties of the same species. there are no known cases of immunity there are no known cases of immunity

to insects in maizeto insects in maize

From: Jennifer Kling Crop and Soil Science Oregon State University

Mechanisms of resistanceMechanisms of resistance NonpreferenceNonpreference ( (antixenosisantixenosis) – characteristics of the plant are ) – characteristics of the plant are

not favored by the insect for ovipositioning, feeding, or shelternot favored by the insect for ovipositioning, feeding, or shelter AntibiosisAntibiosis – feeding by the insect results in – feeding by the insect results in

reduced fecundityreduced fecundity decreased sizedecreased size abnormal lifespanabnormal lifespan increased mortalityincreased mortality

ToleranceTolerance – the plant is able to grow and reproduce, or to – the plant is able to grow and reproduce, or to repair injury despite a level of insect infestation that would repair injury despite a level of insect infestation that would damage a susceptible hostdamage a susceptible host may exert less selection pressure on the insect population to overcome may exert less selection pressure on the insect population to overcome

the resistancethe resistance not harmful to beneficial insectsnot harmful to beneficial insects


ResistanceResistance

• A variety may possess A variety may possess more than one mechanismmore than one mechanism of resistance of resistance– all types of resistance to stem borers in maize have been all types of resistance to stem borers in maize have been

identifiedidentified• These mechanisms of resistance are These mechanisms of resistance are controlled by different controlled by different

genetic factorsgenetic factors, but effects are interrelated, but effects are interrelated• Degree of resistance may vary from highly resistant to highly Degree of resistance may vary from highly resistant to highly

susceptiblesusceptible• It may be possible to determine experimentally which It may be possible to determine experimentally which

mechanism is involved, but the actual plant characteristic or mechanism is involved, but the actual plant characteristic or compound causing resistance has been identified in only a few compound causing resistance has been identified in only a few casescases

• Selection can be effective without knowing the specific factors Selection can be effective without knowing the specific factors responsible for resistanceresponsible for resistance


Pseudo-resistancePseudo-resistance

host evasionhost evasion ( (avoidanceavoidance)) – variety passes through – variety passes through susceptible phase at a time when the insect population susceptible phase at a time when the insect population is not highis not high

induced resistanceinduced resistance (1) (1) – improvement in crop – improvement in crop management reduces the damage caused by the insectmanagement reduces the damage caused by the insect increased waterincreased water fertilizer applicationfertilizer application

induced resistanceinduced resistance (2) (2) – plant’s defense system is – plant’s defense system is enhanced in response to external physical or chemical enhanced in response to external physical or chemical stimuli (may last a few days)stimuli (may last a few days)

escapeescape – occurs when level of infestation in a field is – occurs when level of infestation in a field is light or unevenly distributed light or unevenly distributed some plants in the field are not exposed to the insectsome plants in the field are not exposed to the insect

these mechanisms may be temporary, and may be these mechanisms may be temporary, and may be confused with true resistanceconfused with true resistance


Host plant resistance to insectsHost plant resistance to insects

Many documented cases in a wide array of crop speciesMany documented cases in a wide array of crop species Breeding programs have been successfulBreeding programs have been successful High return on dollars invested in researchHigh return on dollars invested in research Breeding for insect resistance is not as widely applied or Breeding for insect resistance is not as widely applied or

accepted as a means of pest management as breeding accepted as a means of pest management as breeding for disease resistancefor disease resistance relatively easy to control with the use of insecticidesrelatively easy to control with the use of insecticides insect-rearing programs are expensiveinsect-rearing programs are expensive development of insect-rearing and infestation techniques may development of insect-rearing and infestation techniques may

take several years; requires entomology expertisetake several years; requires entomology expertise artificial infestation may not produce the behavioral or artificial infestation may not produce the behavioral or

metabolic equivalent of an insect population in nature metabolic equivalent of an insect population in nature


RationaleRationale

development of insects with resistance to insecticidesdevelopment of insects with resistance to insecticides adverse effects of insecticides on natural enemies and adverse effects of insecticides on natural enemies and

biodiversitybiodiversity public awareness of health risks and environmental public awareness of health risks and environmental

contamination due to pesticide usecontamination due to pesticide use host plant resistance is usually compatible with IPMhost plant resistance is usually compatible with IPMDeveloping countriesDeveloping countries greater insect pressure in the tropicsgreater insect pressure in the tropics limited access to insecticideslimited access to insecticides potentially greater health hazardspotentially greater health hazards

inadequate farmer traininginadequate farmer training water supply may be limitedwater supply may be limited


Requirements for an effective Requirements for an effective resistance breeding programresistance breeding program

Multidisciplinary teamMultidisciplinary team Good crop husbandryGood crop husbandry Good field plot techniqueGood field plot technique Knowledge of the biology of the insectKnowledge of the biology of the insect

life cyclelife cycle alternate hostsalternate hosts

Genetic resourcesGenetic resources Appropriate level of insect infestationAppropriate level of insect infestation

optimum insect density:damage ratio to allow optimum insect density:damage ratio to allow greatest differences in expression of resistance and greatest differences in expression of resistance and susceptibility susceptibility


Measurement of resistance in Measurement of resistance in the host plantthe host plant

Direct damage to host plantDirect damage to host plant stem and ear damagestem and ear damage leaf necrosis or lesionsleaf necrosis or lesions yield reduction (protected vs unprotected)yield reduction (protected vs unprotected) rating scales are commonrating scales are common

Simulated injurySimulated injury e.g., toxic effects due to application of crude extract of e.g., toxic effects due to application of crude extract of

green bug in sorghumgreen bug in sorghum Plant characteristics associated with resistancePlant characteristics associated with resistance

morphological e.g., rind thickness in maize morphological e.g., rind thickness in maize (penetrometer score)(penetrometer score)

chemical compounds known to cause antibiosis chemical compounds known to cause antibiosis


Indirect measures of resistance Indirect measures of resistance in the pestin the pest

insect abundanceinsect abundance sampling nets, traps, or actual countssampling nets, traps, or actual counts

insect feeding and developmentinsect feeding and development amount of food consumed amount of food consumed duration of larval/pupal developmentduration of larval/pupal development fecundityfecundity insect survivalinsect survival weight and size of insectsweight and size of insects sex ratiosex ratio proportion of insects entering diapause proportion of insects entering diapause


Insect behaviorInsect behavior

Measures of antixenosisMeasures of antixenosis responses to volatile stimuli responses to volatile stimuli olfactory responsesolfactory responses

olfactometersolfactometers electroantennogramselectroantennograms electroretinogramselectroretinograms electronic feeding monitors electronic feeding monitors


Natural field infestationNatural field infestation

AdvantagesAdvantages no extra costno extra cost number of entries is not limitednumber of entries is not limited

DisadvantagesDisadvantages distributions in the field are not uniformdistributions in the field are not uniform infestation may be ineffective in some years, reducing progress infestation may be ineffective in some years, reducing progress

from selectionfrom selection natural enemies may cause uneven infestation and damage natural enemies may cause uneven infestation and damage

symptomssymptoms may be difficult to synchronize the lifecycle and presence of the may be difficult to synchronize the lifecycle and presence of the

pest with the susceptible growth stage of the plantpest with the susceptible growth stage of the plant May be acceptable for preliminary disease screenings, May be acceptable for preliminary disease screenings,

but artificial infestation is necessary for accurate but artificial infestation is necessary for accurate evaluationsevaluations


Artificial infestationArtificial infestation Requires mass rearing of the insectRequires mass rearing of the insect

on growth mediumon growth medium on suitable hoston suitable host requires space in lab or greenhouserequires space in lab or greenhouse rearing and oviposition chambers with temperature rearing and oviposition chambers with temperature

and humidity controland humidity control laboratory strains of the insect may change over timelaboratory strains of the insect may change over time

Insects are available year-round, at the right timeInsects are available year-round, at the right time Level and time of infestation can be controlledLevel and time of infestation can be controlled Field infestation is labor intensiveField infestation is labor intensive


Enhanced field infestationEnhanced field infestation Control natural enemiesControl natural enemies with use of selective insecticides with use of selective insecticides

or cagesor cages Spreader rowsSpreader rows (trap crops) may be used to enhance (trap crops) may be used to enhance

natural infestationnatural infestation Stagger plantingsStagger plantings throughout the season to achieve better throughout the season to achieve better

synchronization with insect life cyclesynchronization with insect life cycle ReplantReplant in the same field in the same field Late plantingsLate plantings or crops grown in the 2 or crops grown in the 2ndnd rainy season rainy season

(bimodal rainfall pattern) may have higher insect incidence(bimodal rainfall pattern) may have higher insect incidence Use hot-spotsUse hot-spots, where the insects are known to occur , where the insects are known to occur

regularly in high numbers each seasonregularly in high numbers each season Light traps, pheromone traps, and kairomone trapsLight traps, pheromone traps, and kairomone traps can be can be

used to attract natural insect populationsused to attract natural insect populations Collect insectsCollect insects in nearby fields and in nearby fields and releaserelease in test plots in test plots


CagingCaging under greenhouse and field conditionsunder greenhouse and field conditions maintains uniform insect pressure on the test maintains uniform insect pressure on the test

entriesentries test plants infested at the same phenological test plants infested at the same phenological

stagestage prevents insects from migrating away from the prevents insects from migrating away from the

test plantstest plants protects insects from natural enemies protects insects from natural enemies

http://www.icrisat.org/text/research/grep/homepage/grephomepage/archives/tech.htm

Stem borers in maizeStem borers in maize European corn borer (ECB) European corn borer (ECB) Ostrinia nubilalisOstrinia nubilalis (Hübner) (Hübner) Fall armyworm (FAW) Fall armyworm (FAW) Spodoptera frugiperdaSpodoptera frugiperda (Smith) (Smith) Southwestern cornborer (SWCB) Southwestern cornborer (SWCB) Diatraea grandiosella Diatraea grandiosella

(Dyar)(Dyar) Sugarcane borer (SCB) Sugarcane borer (SCB) Diatraea saccharalis Diatraea saccharalis (F)(F) Corn earworm Corn earworm HelicoverpaHelicoverpa (= (=HeliothisHeliothis) ) zeazea (Boddie) (Boddie) Asian corn borer Asian corn borer Ostrinia furnacalis Ostrinia furnacalis (Guenee)(Guenee) Pink borer Pink borer Sesamia nonagrioidesSesamia nonagrioides (Lefebvre) (Lefebvre) African speciesAfrican species African maize stalk borerAfrican maize stalk borer Busseola fusca Busseola fusca (Fuller) (Fuller) African sugarcane borerAfrican sugarcane borer Eldana saccharina Eldana saccharina (Walker)(Walker) Pink stalk borerPink stalk borer Sesamia calamistis Sesamia calamistis (Hampson) (Hampson) Spotted stem borerSpotted stem borer Chilo partellus Chilo partellus (Swinhoe) (introduced) (Swinhoe) (introduced)


Causal agentsCausal agents

Sesamia nonagrioides Lefebvre ‘pink borer’ ‘la sesamie’ Noctuidae, Amphipyrinae

Ostrinia nubilalis Hübner‘European corn borer’ Pyralidae, Pyraustinae

Lepidopterans

Slide courtesy Isabel Vales From: Jennifer Kling Crop and Soil Science Oregon State University

Sesamia nonagrioidesSesamia nonagrioides: : Population dynamicsPopulation dynamics

Slide courtesy Isabel Vales

Several generations per yearSeveral generations per year Yield and quality losses: up to 30% yield losses in maizeYield and quality losses: up to 30% yield losses in maize Integrated pest management neededIntegrated pest management needed

agronomic, chemical, biological, and genetic controlagronomic, chemical, biological, and genetic control


Field infestation techniquesField infestation techniques

Egg massesEgg masses whorl of plant (1whorl of plant (1stst generation European corn generation European corn

borer) borer) leaf sheath (leaf sheath (Sesamia calmistis, Sesamia calmistis, 22ndnd generation generation

European corn borer, European corn borer, Eldana saccharinaEldana saccharina)) agar suspended eggs delivered to silks by agar suspended eggs delivered to silks by

pressure pump (corn ear worm)pressure pump (corn ear worm)

Larvae Larvae applied to silks with a brush (corn ear worm)applied to silks with a brush (corn ear worm) mixed with cob grits and applied by bazookamixed with cob grits and applied by bazooka


Rating scales used for stem Rating scales used for stem borersborers

Typically from 1 (resistant) to 9 (susceptible)Typically from 1 (resistant) to 9 (susceptible) Leaf feedingLeaf feeding

size and number of lesions on leavessize and number of lesions on leaves dead hearts (growing point destroyed)dead hearts (growing point destroyed)

Stem damageStem damage stem tunnellingstem tunnelling frass on maize leaf sheaths and collarsfrass on maize leaf sheaths and collars stalk breakagestalk breakage

Ear damageEar damage cm of feeding from tipcm of feeding from tip frass on earsfrass on ears

Photos courtesy Isabel ValesFrom: Jennifer Kling Crop and Soil Science Oregon State University

Sources of resistanceSources of resistance Antiguan landraces showed high level of Antiguan landraces showed high level of

resistance to 1resistance to 1stst and 2 and 2ndnd generation ECB. Good generation ECB. Good generalized resistance to borers.generalized resistance to borers.

Zapalote chicoZapalote chico – Mexican landrace with – Mexican landrace with resistance to corn earworm (CEW)resistance to corn earworm (CEW)

Mp lines from Mississippi StateMp lines from Mississippi State CIMMYT populations with multiple borer CIMMYT populations with multiple borer

resistance:resistance: MBR subtropical populationMBR subtropical population MIRT tropical populationMIRT tropical population

Mo17 and TZi4 (tropical conversion)Mo17 and TZi4 (tropical conversion) resistant to resistant to Sesamia calamistisSesamia calamistis


Genetics of resistance to stem Genetics of resistance to stem borersborers

Summary of a number of studiesSummary of a number of studies polygenicpolygenic

cases of single gene resistance to cases of single gene resistance to insects are less common than for insects are less common than for disease resistance in plantsdisease resistance in plants

primarily additive gene actionprimarily additive gene action largely due to GCAlargely due to GCA

Granados and Paliwal, 2000 From: Jennifer Kling Crop and Soil Science Oregon State University

Genetics of the resistanceGenetics of the resistance Quantitative traitsQuantitative traits

Stem resistanceStem resistance Ear resistanceEar resistance Yield under infestationYield under infestation

General combining ability (GCA), specific General combining ability (GCA), specific combining ability (SCA), reciprocal effects (R) combining ability (SCA), reciprocal effects (R)

Diallel of 10 inbred lines (resistant and Diallel of 10 inbred lines (resistant and susceptible)susceptible) GCA was the most important factor for stem and GCA was the most important factor for stem and

ear traitsear traits GCA, SCA were significant for yield under GCA, SCA were significant for yield under

infestationinfestation

Butron et al. 1999; Notes from Isabel Vales


QTL’s for resistanceQTL’s for resistance

Insect resistance is a good candidate for Insect resistance is a good candidate for MASMAS

QTLs identified for QTLs identified for 22ndnd generation ECB in US temperate maize generation ECB in US temperate maize SWCB and AmSB in tropical maize (CIMMYT)SWCB and AmSB in tropical maize (CIMMYT)

Some QTL regions were common to both speciesSome QTL regions were common to both species Sesamia nonagrioidesSesamia nonagrioides in Spain in Spain

Morphological resistance Morphological resistance factorsfactors

Tight husksTight husks Reduced trichome density, delayed pubescence Reduced trichome density, delayed pubescence

less preferred by CEWless preferred by CEW High silica content in cellsHigh silica content in cells

imparts some resistance to ECBimparts some resistance to ECB Epidermal cell wall thicknessEpidermal cell wall thickness

highly correlated with leaf feeding damage highly correlated with leaf feeding damage by SWCB and FAWby SWCB and FAW

Others…Others…

Smith, in Mihm (ed.), 1997

AllelochemicalsAllelochemicals

Maysin (C-glycosylflavone) in maize silksMaysin (C-glycosylflavone) in maize silks first shown to inhibit growth of CEW in Zapalote first shown to inhibit growth of CEW in Zapalote

chico (Snook chico (Snook et alet al., 1993)., 1993) now known to occur in high concentration in a now known to occur in high concentration in a

number of populations and inbred linesnumber of populations and inbred lines DIMBOA in leavesDIMBOA in leaves

antibiotic effect on ECB, and to a lesser extent antibiotic effect on ECB, and to a lesser extent SWCB and FAWSWCB and FAW

Phenolic acid in maize grainPhenolic acid in maize grain associated with resistance to maize storage associated with resistance to maize storage

pestspests related to the hardness of the grainrelated to the hardness of the grain


Fungal interactions with stem Fungal interactions with stem borersborers

Damage to the ear by ECB and other ear Damage to the ear by ECB and other ear borers associated with increased borers associated with increased incidence of mycotoxinsincidence of mycotoxins FusariumFusarium spp. spp. Aspergillus flavusAspergillus flavus

Bt lines have been shown to have lower Bt lines have been shown to have lower levels of some mycotoxins than their non-levels of some mycotoxins than their non-Bt isogenic linesBt isogenic lines

Conventional resistance to insects may Conventional resistance to insects may also reduce levels of mycotoxinsalso reduce levels of mycotoxins

Breeding schemesBreeding schemes

Backcrossing Backcrossing ECB resistance from Cornell Composite ECB ECB resistance from Cornell Composite ECB

introgressed into elite temperate inbred linesintrogressed into elite temperate inbred lines Temperate lines with borer resistance Temperate lines with borer resistance

converted for resistance to maize streak virus converted for resistance to maize streak virus at IITAat IITA

Granados and Paliwal, 2000


Breeding schemesBreeding schemes Recurrent selection: IntrapopulationRecurrent selection: Intrapopulation

EPS12 - selection for EPS12 - selection for stalk tunnellingstalk tunnelling resistance (Butron resistance (Butron et al.et al. 2005) 2005) Half-sib selection for resistance to Asian stem borer in the Half-sib selection for resistance to Asian stem borer in the

PhilippinesPhilippines Full-sib family selection for resistance to Full-sib family selection for resistance to Chilo partellusChilo partellus in India in India full-sib, half-sib Sfull-sib, half-sib S11 family selection for MBR at CIMMYT family selection for MBR at CIMMYT SS11 family selection for resistance to family selection for resistance to Eldana saccharinaEldana saccharina and and Sesamia Sesamia

calamistiscalamistis at IITA at IITA SS1 1 half-sib selection for resistance to Fall armyworm (FAW-CC)half-sib selection for resistance to Fall armyworm (FAW-CC)

Recurrent selection: InterpopulationRecurrent selection: Interpopulation EPS20 (Reid) and EPS21 (non-Reid) EPS20 (Reid) and EPS21 (non-Reid) –– selection for yield under selection for yield under

infestationinfestation TransformationTransformation

Transgenic varieties produce Bt toxin for resistance to ECB and fall Transgenic varieties produce Bt toxin for resistance to ECB and fall armywormarmyworm


Bt cornBt corn Bt corn contains the gene from a soil bacterium Bt corn contains the gene from a soil bacterium Bacillus Bacillus

thuringiensisthuringiensis Produces a toxin that protects against the European corn borer and Produces a toxin that protects against the European corn borer and

other insectsother insects EPA approved Bt corn for use in 1995 (Cry1Ab, Cry1Ac)EPA approved Bt corn for use in 1995 (Cry1Ab, Cry1Ac) Production peaked at about 26% of total acreage in 1999Production peaked at about 26% of total acreage in 1999 In 2000, EPA requires that farmers growing Bt corn must plant at In 2000, EPA requires that farmers growing Bt corn must plant at

least 20% of their total corn acreage to a non-Bt variety least 20% of their total corn acreage to a non-Bt variety ‘‘StarLink’ version of Bt (Cry9C protein) was approved only for StarLink’ version of Bt (Cry9C protein) was approved only for

animal feed in 1999 – concerns over possible allergenicityanimal feed in 1999 – concerns over possible allergenicity Problem – grain dealers do not maintain separate stocks of corn for Problem – grain dealers do not maintain separate stocks of corn for

feed and food, nor for GMO vs conventional hybridsfeed and food, nor for GMO vs conventional hybrids Aventis removed ‘StarLink’ from the market in 2000, after it was Aventis removed ‘StarLink’ from the market in 2000, after it was

found in human food suppliesfound in human food supplies


MAS for insect resistanceMAS for insect resistance

traditional approaches have been successful, traditional approaches have been successful, but progress is slow and sufficient genetic but progress is slow and sufficient genetic variation is not found in some species variation is not found in some species

wild relatives are valuable sources of insect wild relatives are valuable sources of insect resistance for many crop species; MAS could resistance for many crop species; MAS could reduce linkage dragreduce linkage drag

permits pyramiding of resistance genes; may permits pyramiding of resistance genes; may be particularly useful for developing be particularly useful for developing populations with resistance to multiple species populations with resistance to multiple species of insectsof insects

Yencho et al., 2000 From: Jennifer Kling Crop and Soil Science Oregon State University

Lessons from stem borers in Lessons from stem borers in maizemaize

Knowledge of the causal agent population dynamics, Knowledge of the causal agent population dynamics, the host plant life cycle and plant-pathogen the host plant life cycle and plant-pathogen interactions is very importantinteractions is very important

Artificial infestation is needed for accurate screeningArtificial infestation is needed for accurate screening Polygenic inheritance, GCA, and additive gene action Polygenic inheritance, GCA, and additive gene action

are most importantare most important Recurrent selection has been effective in a number of Recurrent selection has been effective in a number of

populationspopulations Direct measurements of damage on the host plant Direct measurements of damage on the host plant

are most effective selection criteriaare most effective selection criteria MAS can be used to complement conventional MAS can be used to complement conventional

breedingbreeding


Insect Resistance to Insect Resistance to Bacillus thuringiensis (B.t.)Bacillus thuringiensis (B.t.)

1970 Introduction of 1970 Introduction of B.t.B.t. products products 1985 First reports of 1985 First reports of B.t.B.t. resistance resistance

McGaughey, 1985McGaughey, 1985

Additional reports of Additional reports of B.t.B.t. resistance resistance Tabashnik, Cushing, Finson, and Johnson, 1990Tabashnik, Cushing, Finson, and Johnson, 1990 Tabashnik, 1994Tabashnik, 1994 Lui, Tabashnik, Dennehy, Patin, and Bartlett, Lui, Tabashnik, Dennehy, Patin, and Bartlett,

19991999

Carol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State UniversityCarol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State University

Insect-Protection TraitsInsect-Protection Traits

YieldGardYieldGard® ® Corn BorerCorn Borer Registered 1997Registered 1997

HerculexHerculex™™ I I Registered 2002Registered 2002

YieldGardYieldGard®® Rootworm Rootworm Registered 2003Registered 2003

YieldGardYieldGard®® Plus Plus Registered 2003Registered 2003

Carol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State UniversityCarol Pilcher Marlin Rice Jon Tollefson Department of Entomology Iowa State University

Key Component of Insect Key Component of Insect Resistance Management is Resistance Management is

RefugeRefuge

Refuge is a block or strip of a crop Refuge is a block or strip of a crop that does not contain the technology that does not contain the technology traittrait e.g., a block or strip of corn that does e.g., a block or strip of corn that does

not contain the not contain the B.t.B.t. technology for technology for control of the corn rootwormcontrol of the corn rootworm

Refuge StrategyRefuge StrategyGoal of non-B.t. refuge is to maintain susceptible insects

in the population that can mate with rare resistant insects and produce susceptible insects in next

generation

= susceptible to B.t. corn = resistant to B.t. corn

Non-B.t. RefugeB.t. Crop

Growers Must Sign a Growers Must Sign a Technology Agreement and Technology Agreement and

Agree to Follow the Agree to Follow the Insect Resistance Insect Resistance

Management RequirementsManagement Requirements European corn borer insect-protected traitsEuropean corn borer insect-protected traits Corn rootworm insect-protected traitsCorn rootworm insect-protected traits

IRM Requirements IRM Requirements European Corn Borer Insect-European Corn Borer Insect-

Protection TraitsProtection Traits Growers must plant at least a 20% non-Growers must plant at least a 20% non-

B.t.B.t. refuge refuge Growers must plant Growers must plant B.t.B.t. corn within ½ corn within ½

mile of a refuge, preferably within ¼ mile of a refuge, preferably within ¼ milemile

Strip-planted refuges must be at least Strip-planted refuges must be at least 4 rows wide and preferably 6 rows wide4 rows wide and preferably 6 rows wide

IRM Requirements IRM Requirements European Corn Borer Insect-European Corn Borer Insect-

Protection TraitsProtection Traits

Refuges can be treated with Refuges can be treated with insecticides if economic thresholds insecticides if economic thresholds are reached for one or more target are reached for one or more target insectsinsects

Microbial Microbial B.t.B.t. insecticides must not insecticides must not be applied to refugebe applied to refuge

Insect Resistance Insect Resistance ManagementManagement

Refuge possibilities for Refuge possibilities for YieldGardYieldGard®® Corn Borer and Corn Borer and

HerculexHerculex™™ I I

B.t. corn

Refuge

Perimeter Block Split Planter

Perimeter RefugePerimeter Refuge

Advantages:Advantages: 20% refuge can be 20% refuge can be

treated if neededtreated if needed Can harvest Can harvest B.t.B.t. and and

non-non-B.t.B.t. separately separately Minimize number of Minimize number of

seed changesseed changes Limitations:Limitations:

May need to match May need to match herbicide toleranceherbicide tolerance

Block RefugeBlock Refuge Advantages:Advantages:

Good mixing of insectsGood mixing of insects 20% refuge can be 20% refuge can be

treated if neededtreated if needed Can harvest Can harvest B.t.B.t. and and

non-non-B.t.B.t. separately separately Limitations:Limitations:

More time changing More time changing seed & cleaning seed & cleaning hoppershoppers

May need to match May need to match herbicide toleranceherbicide tolerance Non-B.t. corn

0

5

10

15

20

% I

NF

ES

TA

TIO

N

1970 1980 1990YEAR

LOSS OF THE H-5 GENE

NO-RESISTANCE

H-5

0

20

40

60

80

% H

-5 P

LA

NT

ED

1970 1980 1990YEAR

DEPLOYMENT OF H-5 WHEAT

Figure 1b

0

5

10

15

% I

NF

ES

TA

TIO

N

1960 70 80 1990YEAR

LOSS OF THE H-6 GENE

NO-RESISTANCE

H-6

0

20

40

60

80

% H

-6 P

LA

NT

ED

1960 70 80 1990YEAR

DEPLOYMENT OF H-6 WHEAT

Figure 1c

Percentage of Bt Corn and Bt Cotton Planted in the US

0

5

10

15

20

25

30

35

40

45

95 96 97 98 99 0O O1 O2 O3

Bt Corn

BT Cotton

% o

f to

tal a

cres

Source: USDA

breeding for insect resistance hessian fly in wheat a case study stephen harrison fangneng huang...

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