GEM as a source for
disease and insect resistance
& Crop Biosecurity
Wm. E. Dolezal
Pioneer Hi-Bred International, Inc.
Johnston, IA
GEM Cooperator Meeting - 2003
Hyatt Regency Hotel
Chicago, IL
December 10, 2003
Topics to discuss today
• Importance of Maize Genetic Resources in Crop Biosecurity
• Need to identify new source for disease and insect resistance
• Screening/pathogen population monitoring opportunities worldwide
• The difficulty in screening material that is not crossed onto a locally
adapted tester
• Suggestions in the use of these GEM germplasm in breeding
programs
Importance of Maize Genetic
Resources in Crop Biosecurity
The events of September 11, 2001 has changed our world.
• What was not considered possible is now plausible
• Economic disruption – crop bioterroristic targets – Corn & soybean?
• Relatively “low tech” effort needed.
• Historical efforts during the cold war by the super powers
Are we broad enough with our genetic diversity of
our major commercial maize germplasm?
Stiff Stalk X Non-Stiff Stalk (Lancaster, Etc)
Importance of Maize Genetic
Resources in Crop Biosecurity
Unintentional Pest Introduction through
Worldwide Trade
Once major natural barriers to pest
movement now easily
overcome by modern transportation
Example: CRW introduction into Europe
Unintentional Pest Introductions through man’s activities:
• Since 1980, over 200+ Non-indigenous species have been
intercepted by the USDA. 59 economically damaging.
• Free Trade agreements have allowed more
INTERNATIONAL movements of
commodities and containerized freight shipments.
Importance of Maize Genetic
Resources in Crop Biosecurity
Are we operating our
plant breeding programs under an outdated model
of genetic susceptibility to a new series of Exotic PESTS and
higher introduction risk?
Some Recent Examples:
• Soybean Rust
• Soybean Aphid
• Russian Wheat Aphid
• Sorghum Ergot
• Corn Rootworm (Europe)
Need to identify new source of
insect & disease resistance
Summary GEM Disease/Entomology Collaborations - 2003
18 Collaborations
• 4 Private Companies:
(All In Kind Support)
AgriSource, Nidera, Pioneer,
& Professional Seed
• 7 Universities (SCA’s):
Cornell, LSU, NCSU, Ohio St. Univ.
Texas A& M(2), Univ’s of DE & IL
• 6 USDA-ARS
GA, MO, MS(2), & NC(2)
(USDA Support)
Countries
• Argentina, Thailand, USA
Identifying Worldwide
Disease Screening Locations - GEM
DISEASE NAME
GEM Collaborator
Northern Leaf Blight:
Northern Leaf Spot
Southern Leaf Blight:
Southern Rust:
Eyespot:
Common Rust:
Tropical Rust:
Stewart’s Wilt:
Goss’ Wilt:
Gray Leaf Spot:
Head Smut:
Common Smut:
Corn Stunt Spiroplasma:
MDMV:
MDMCPX:
HPV:
MRDV/MRFV:
Maize Stripe Virus:
CLN:
PHI,
Professional Seed
Prof. Seed, PHI, NCSU
PHI
Prof. Seed
PHI
--Prof. Seed
--Prof. Seed, NCSU, OSU
--------OSU?
--Nidera, PHI
-----
SHANE SCOTT 021397
Identifying Worldwide
Disease & Insect Screening
Locations
- GEM
DISEASE/INSECT
NAME GEM
Collaborator
Bacterial Stalk Rot
--Sorghum Downy Mildew (S.macro.) --Philippine Downy Mildew (S. phil.): AgriSource
Diplodia Stalk Rot:
--Anthracnose Stalk Rot:
Cornell, Univ.-Del
Fusarium Stalk Rot:
--Gibberella Stalk Rot:
--Diplodia (D. maidis) Ear Rot: PHI,
Diplodia (D. macrospora):
--Fusarium Ear Rot:
PHI, NCSU,
Gibberella Ear Rot:
--Mycotoxins:
Aflatoxin
Fumonisin
DON
LSU, Texas A&M,
USDA-ARS-GA,MS
Univ-IL,USDA-ARS-NC
---
Insects:
CEW
CRW
ECB
SWCB
SHANE SCOTT 021397
Texas A&M
PHI, Univ. IL, USDA-ARS-Mo
PHI, Univ-IL
USDA-ARS-MS
GEM as a “target rich” source for identifying new
sources of resistance to major crop performance traits
Stalk Lodging – Premature death and standability
Additional Opportunities to enlist other Worldwide Collaborators
Proactive effort by USDA-APHIS
Collect pest information before before pest arrival
• Africa
• Asia
• Central & South America
Solicit New Members/Cooperators?
• Public
• Agricultural Universities.
• NGO Research Centers / CGIAR
• Government Agricultural Research Units
• Multinational Maize Breeding Companies
Screening/pathogen population
Monitoring opportunities worldwide
Team Involvement of Pathologist / Entomologist, working
with Plant Breeders, to Understand Pest Population Biology
• Determine stability of host resistance by
understanding the existing variability in pest population
• Northern leaf blight genes: HT1-3 genes
• Anthracnose – MP305, LB31, exotic
• Rust genes – Rp1’s, Rpp’s,
• Ear molds & mycotoxin production
• Linkages with maize genomic programs
Southern Corn Rust
(Puccinia polysora)
Central Brazil – March 2003
Susceptible hybrid – foreground
Resistant hybrid - background
What is our current ability to determine races
using host differentials?
• A. Roberts (1963) rust collection
& host differential sets are mostly gone!
• Rpp9 gene in use but not effective in
parts of So. America, Asia and SE USA
• What are the identity of the other races in these regions?
• Are specific sources of resistance identified for each race
or are there partial resistance sources available?
GEM Collaborators Span the World
Offers unique opportunity for characterizing material
study plant pathogen populations
and
discover resistant/tolerant germplasm
Example: Race, strain or biotype differentiation
• Puccinia polysora
• Asian, So. American & USA isolates
• Maize Rio Cuarto Virus / Maize Rough Dwarf Virus
•Big Advantage of GEM – Yield is a major selection component
• Must avoid the “Greeny Winnies”
• Resistance without yield is NOT a winner!
• Balance: ear size (yield) & pest resistance
Yield without yield stability (disease/insect resistance)
It is just as bad!
The difficulty in screening material that is
not crossed onto a locally adapted tester
Difficult to measure assigned disease/insect trait when you have
poor plant development due to choice of non - adapted tester.
Makes the job much more difficult to utilize other worldwide
screening locations to test GEM material.
• cross onto adapted tester that is good for other key
agronomic traits but poor for the trait of interest
Data collected from GEM Screening locations
Top
Quality
Insure adequate disease & insect pressure
• measure against an appropriate
maturity & trait check (B73, SX19, etc).
• be aware of gene insertions (B73Ht1)
Insure that a well developed ear has formed when
collecting late season traits (foliar, ears & stalk traits)
Other Testing Complications:
Sensitivity to common herbicides
2003 Herbicide Damage
Johnston, IA
North Carolina
GEM Cooperators: Earlier generation screening for lethals?
• Systematic screening of common herbicide chemistry?
• Compiling data on any reports of injury?
Cuba164:S1517-163-1-B
Ramosa gene?
Displayed both at
• Johnston, IA
• Woodland, CA
Both locations
experienced heat
and drought stress
Suggestions in the use of these GEM
germplasm in breeding programs
• Making GEM cross onto locally adapted
tester that is resistant/tolerant to most
diseases but susceptible to specific trait
• Other suggestions?
Thank you for this opportunity to
participate & for your attention!
SHANE SCOTT 1/97