1 Host Plant Resistance to Fall Armyworm B.M.Prasanna Director, CIMMYT Global Maize Program & CGIAR Research Program MAIZE Email: [email protected]Accra; July 19, 2017 Click to buy NOW! P D F - X C h a n g e w w w . t r a c k e r - s o f t w a r e . c o m Click to buy NOW! P D F - X C h a n g e w w w . t r a c k e r - s o f t w a r e . c o m
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Host Plant Resistance to Fall Armyworm · 2017-08-02 · MLN Phytosanitary Community of Practice Creating awareness at various levels Impact assessment Insect-vector dynamics ICIPE
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CIMMYT, during the1980s and 1990s,developed an arrayof populations aswell as elite inbredlines (>60 CMLs) withresistance to FAW,derived mainly fromthe Caribbean maizegermplasm.
Some of the eliteCIMMYT-deriveddrought-tolerantlines are highlysusceptible toFAW attack. Needfor rapidconversion of theFAW-susceptiblelines into resistantversions..
• USDA-ARS (Mississippi) utilized CIMMYT’s FAWresistant tropical maize germplasm, besidestemperate maize germplasm, in developing andregistering a series of temperate maize inbredlines with FAW resistance (e.g., Mp704-Mp708,Mp713, Mp714 and Mp716).
• Conventional breeding for FAW resistance,however, took a backseat after the advent of Btmaize in the US in the 1990s.
†AF indicates the line was developed and released as a source of resistanceto aflatoxin accumulation; FAW indicates the line was developed andreleased as a source of resistance to fall armyworm leaf feeding damage.
§Fall armyworm leaf feeding damage sustained by germplasm lines grownin 2015 and 2016 was rated on a scale of 0 (no damage) to 9 (heavy damage)14 days after plants were infested with 30 neonates each.
Source: Marilyn Warburton (USDA-ARS)
Germplasm line Resistance†Aflatoxin (ng/g)‡
Fall Armywormdamage§
LogarithmicMean
GeometricMean
Mp313E AF 0.37 1 6.9Mp420 AF 1.29 3 7.3Mp715 AF 0.99 2 6.4Mp717 AF 2.89 17 7.3Mp719 AF 1.98 6 6.7Mp707 FAW 6.53 507 4.4Mp708 FAW 4.59 97 3.6Mp713 FAW 6.73 838 3.8Mp714 FAW 5.67 288 3.9Mp716 FAW 6.58 721 3.5
What is the basis for conventional resistance to FAW?
• Mp708 and FAW7050 (resistant): elevated defensiveproteins following insect herbivory (greaterconversion of photosynthates to defensive proteins);higher amino acid and glucose contents; constitutiveaccumulation of jasmonic acid.
• Susceptibility of Ab24E to S. frugiperda was due to ahigh P/C ratio (protein-to-total non-structuralcarbohydrates) and a low level of induced defensivecompounds.
§ (E)-β-caryophyllene, a terpenoid associated with resistance, isreleased constitutively in Mp708.
§ FAW-fed samples of both Mp708 (resistant) and Tx601(susceptible) showed high transcript number of tps23, the generesponsible for the synthesis of (E)-β-caryophyllene.
§ FAW larvae show a preference for Tx601 whorl tissue over Mp708tissue; dosage of Tx601 whorl with (E)-β-caryophyllene repels theFAW!
§ Antibiosis was detected in the sorghum landraceaccessions from Honduras -- San Bernardo III, Hilate-179, Piña-61, and Lerdo-104.
§ A hypothesis, based on differential selection andincreased selection pressure brought about throughintercropping with maize, was presented to explain thedevelopment of antibiosis in these landracepopulations.
§ At 14 d after infestation, IS4023C, IS7399C,IS6962C, IS7724C, IS7695C, and IS1l51C hadsignificantly less leaf damage (rating < 5.5) thanthe resistant check CM1821 (rating 6.3).
§ Laboratory bioassays showed that ISI056C,IS2177C, IS2246C, IS4023C. IS7399C, and ISl2680C had a significantly higher antibioticresistance than CM1821.
1 Bazooka(UH5354) 2013 Uganda Being commercialized by NASECO
2 H12ML 2013 Kenya Certified seed to be produced andcommercialized by KSC in 2017
3 H13ML 2014 KE Bulking breeder seed in progress byKSC, following Kenya’s regulations
4 Meru HB607 2014 Tanzania Certified seed expected to beproduced by Meru Agro in 2017
5 WE5135 2017 KE Recommended for release (KALRO)6 WE5136 2017 KE Recommended for release (KALRO)7 WE5138 2017 KE Recommended for release (KALRO)8 WE5139 2017 KE Recommended for release (KALRO)9 WE5140 2017 KE Recommended for release (KALRO)
10 WE5135 TZ; UG NPT211 WE5136 TZ; UG NPT212 WE5139 TZ; UG NPT213 WE5141 TZ; UG NPT2
14 WE6108 KE, TZ,UG
NPT2
15 WE6109 KE NPT216 WE6110 KE NPT217 WE6111 KE NPT218 KATEH15-01 KE NPT119 KATEH15-02 KE NPT120 KATEH15-03 KE NPT1
9 hybrids alreadyreleased in MLN-affectedKE, TZ and UG within 5years, and 11 morein pipeline forrelease!
450 tons of certifiedseed of three hybrids(Bazooka, H12ML &Meru HB607) producedand delivered to farmersin 2017.
Short-term (within 2 years)– Set-up FAW insect-rearing and germplasm screening facilities– Screen available insect-resistant hybrids/varieties, if already
available (e.g., Stem-borer tolerant CIMMYT hybridsdeveloped and released through IRMA Project); Scale-uppromising hybrids; Deploy in targeted geographies
– Validate already available FAW-resistant inbred lines(CIMMYT; exotic) against FAW populations in Africa, andidentify most promising germplasm
– Test the efficacy of Bt maize (MON810; MON89034) underConfined Field Trials (CFTs) against FAW in Africa (incountries that are willing to adapt GM maize as a solutionagainst FAW)
Host Plant Resistance to FAW: A Tiered ApproachClick t
Medium-term (2-4 years)– Discover/validate genomic regions for FAW resistance in
maize, and develop production markers for large-effect QTL– Implement a fast-tracked breeding program to develop new
pre-commercial hybrids with FAW resistance and otherrelevant adaptive traits; similar efforts in other crops, ifpromising germplasm is found.
– Release 2nd-generation FAW-resistant maize hybrids for Africathrough NPTs; Seed scale-up and deployment
– Implement an accelerated/fast-track breeding program todevelop next-generation FAW-resistant hybrids
– Biosafety clearance and approvals for open-field testing of GMbased options in willing African countries, with simultaneousawareness generation efforts at various levels
Long-term (4 years and beyond)– Large-scale deployment of 1st and 2nd generation FAW
resistant maize varieties in Africa in partnership with thecommercial seed sector
– A strong breeding pipeline in different crops withconventionally-derived resistance to FAW incorporated inproduct pipelines, with rapid increase in genetic gain for thetrait
– Release of GM-based FAW resistant varieties in differentcrops, followed by seed scale-up and deployment, withappropriate stewardship and insect-resistant managementstrategies adapted to the African context.
In Conclusion…• Insufficient attention has been given to the integration of
conventionally-derived resistance with other IPM tactics ineffective management of insect-pests of crops in general.
• We need to effectively utilize and quantify the benefitsof host plant resistance in multi-tactic IPM programs.
• Keys to overcoming the barriers:– Systematic analysis of compatibility and possible synergies
between host plant resistance with other IPM approaches(e.g., biological and chemical control) with regard to FAW inAfrica
– Increased application of modern genetic tools in acceleratingbreeding for improved Africa-adapted varieties with FAWresistance and other farmer-preferred traits
– A more quantitative approach to understanding the cost-benefits of various IPM approaches