Why breeding rust resistant varieties is

not sufficient to control Yellow Rust

Hans-Joachim Braun

CIMMYT

International Wheat Stripe Rust Symposium

Aleppo, Syria

April 18 – 20, 2011

Importance of wheat

• Globally the most important food crop

• Second most important food crop in the developing world after rice

• Food to 2.5 billion poor people (< 2 USD) in 89 countries

• Provides calories (20%) and protein (20%) in LDC

• Most traded food crop

Rank 1

Rank 2

Rank 3

Importance of Wheat as calorie source (2005-07)

Percentage of daily calories from Wheat

> 40%

> 30-39%

> 20-29%

> 10-19%

< 10%

Source: FAO 2009

Consumer price index basket weights (2009 or latest available)

0 10 20 30 40 50 60

India

China

Japan

France

Britain

USA

Food

Energy

Source: Economist, Jan 22, 2011: OECD; IMF; Chinese Nat Bureau of Statistics; Indian Labour Bureau

PM Jawahar Lal Nehru famously said in the early 1960s:

“Everything else can wait but not agriculture”

• Demand for wheat is increasing by

>40%.

• Production lags behind demand

• Further decreasing global stocks

• International markets fail the poor

• Financial realities in first world “bread

baskets” and on global financial markets

do no longer tally with what the poor in

developing countries can pay for food

• Urgent demand to increase and protect

local production in low and middle

income countries

• Genetics + Agronomy + Markets + Risk

management + Policies + Infrastructure

Red alert zone for global

food securityReal wheat prices (USD) 1960 - 2011

Estimated contribution of crop protection (mechanical, biological and

chemical) to wheat production for 2001 – 03. Modified after Oerke 2006.

Add. Production due

to crop Protection

22%

Production without

Crop Protection

50%

Losses

28%

• 1B.1R varieties dominant from Kenya to China

• Basis for Yr resistance / suscepetibility was known

• 5 – 10 years gap from Yr9 virulence occurrence in Kenya

until it reached Asia

• No (?) country has removed 1B.1R varieties from seed

production before an epidemic occurred – but then fast

reaction e.g. Iran, established first class YR facilities,

Pakistan

Losses reported from yellow rust epidemics in CWANA

Region: Central and West Asia (CWANA); Countries;

Turkey, Azerbaijan, Iran, Pakistan, Afghanistan, Syria, T

urkmenistan, and Uzbekistan

•Turkey: 25 % yield loss, in 1991, up to 50 % in 1998.

•Iran: 15 % loss in 1993, 1995.

•Pakistan very significant loss in consecutive years

1990, 1991, 1992.

•Syria and Lebanon: 30% loss in 1988 and 1994

respectively.

•Turkmenistan, Uzbekistan: severe epidemics in 1998.

•Azerbaijan: nearly every year.

•Afghanistan 1991 famine due to yellow rust epidemic

Yellow rust epidemics during last decade of last century

National average wheat yield in years with yellow rust

epidemic in % of average yield of 3 previous and 3

consecutive years

50 60 70 80 90 100 110 120 130 140 150

Tur-92

Tur-98

Iran-93

Iran-95

Pak-92

Pak-91

Pak-90

Syria-88

Syria-94

Leb-88

Leb-94

Uzbek-98

Turkmen-98

Afg-91

National average yield in % of mean yield in years with YR epidemic

National average wheat yield in years with yellow rust

epidemic in % of average yield of 3 previous and 3

consecutive years and potential losses (15%)

50 60 70 80 90 100 110 120 130 140 150

Tur-92

Tur-98

Iran-93

Iran-95

Pak-92

Pak-91

Pak-90

Syria-88

Syria-94

Leb-88

Leb-94

Uzbek-98

Turkmen-98

Afg-91

National average yield in % of mean yield in years with YR epidemic

Country and

year Year+3 Year+2 Year+1

Year with

Yr-Epidemic Year-1 Year-2 Year-3

Tur-92 94 88 106 100 104 104 86

Tur-98 91 100 86 100 89 88 86

Iran-93 106 115 107 100 99 90 86

Iran-95 113 93 92 100 94 87 86

Pak-92 105 95 98 100 92 91 94

Pak-91 103 106 108 100 99 102 94

Pak-90 107 109 101 100 103 95 86

Syria-88 90 82 44 100 74 95 72

Syria-94 72 106 107 100 110 93 71

Leb-88 112 99 108 100 98 75 66

Leb-94 73 111 112 100 103 103 100

Uzbek-98 120 104 101 100 83 82 80

Turkmen-98 101 97 101 100 57 31 64

Afg-91 100 100 101 100 103 110 115

National average wheat grain yield in % of yield in years with yellow rust epidemic

in 3 consecutive (Year +) and previous years (Year-). Source: FAO 2009

In 27 of 42 cases yield greater In 9 of 42 cases yield greater

Losses reported in 1991 from Turkey

FACTS:•Turkey: 25 % yield loss, in 1991,

•Estimates were developed for Gerek 79 by calculating

the mean yield performance of three yellow rust

resistant check cultivars commonly used along with

Gerek 79 in the regional yield trials of the Eskisehir

Agricultural Research Institute. The data from the three

proceeding years were used to compare against Gerek

79.

•Losses are expressed in potential losses

Yellow rust epidemics during last decade of last century

Why is yield in years with yellow rust epidemics not lower?

• Good year for wheat = good year for yellow rust (cool, wet)

• Farmers may apply more N to benefit from good weather

conditions

• Wheat and Yellow Rust grow better with N

• Resistant varieties benefit from climate / N and yield

increases relative to normal year (20 – 30%)

• Yield of susceptible varieties reduced by 20 – 30% =

Yield of susceptible variety like in an average year

• Farmers loose 15 - 30% in extremes up to 50% and high %

of shriveled grains

• NB: This does not apply to very severe epidemics like in

Ethiopia in 2010

Examples for drastic rust control measures

• Barberry eradication program in US

• Sowing winter barley illegal in Denmark (1968) to

prevent infection of spring barley

• Legally defined earliest sowing dates for wheat

• Australian rust control program

Rust Control Measures

• Surveillance Monitoring

• Know genetic make up of major parents in crossing programs

• Hot spot screening – do we need another Njoro?

Hotspots for occurrence of new yellow rust races

Rust Control Measures

• Surveillance Monitoring

• Know genetic make up of major parents in crossing prrgrams

• Hot spot screening – slide -

• No release of susceptible varieties

• No seed multiplication of “Rust Suckers” – after resistance broke

down

• Use APR – no more rust suckers

• Agronomy – control volunteers

• Use BC and Modified BC to fix resistance in dominating cultivars

whose resistance broke down

• Release genetically diverse varieties – CG-centers – NARS –

Mega-varieties how to avoid / can we avoid / should we avoid

• Establish similar testing network for YR as in place for Ug99

• Establish aggressive seed multiplication programs / extension

• One of the most important conditions for an epidemic is that

timely infection can occur in susceptible varieties sown on

large areas, Lang, 1918

• An epidemic will only occur when three factors come together:

Gaeuman (1951)

Virulent pathogen

Susceptible host grown on large areas

Conducive environmental conditions -

• Yr 27 may be the most rapid spread of an important crop

pathogen on the global scale (Hovmoller, 2008).

Countries in the Africa – Asia epidemiological

zone for YR where widely grown varieties are

susceptible to YR (2010)

Major variety replacement programs in Afghanistan, Egypt, Ethiopia, India,

Pakistan, Syria, Uzbekistan - list may not be complete

Ug99 resistant wheat varieties under seed increase 2010–11

Name Sr gene Countries undertaking seed production

NPL BGL AFG EGY ETH PAK IRN YR

CIMMYT name

Danphe#1 a APR (Sr2+) `√ √ √

Picaflor#1b APR (Sr2+) √ √ √ √ √

Quaiu#1c Sr2+SrTmp √ √

Quaiu#2 Sr2+SrTmp √ √ √

Pauraque#1 APR (Sr2+) √ √ √

Becard#1 APR (Sr2+) √ √

Munal#1 APR (Sr2+) √ √ √ √

Francolin#1 APR (Sr2+) √ √ √

Chonte#1d APR (Sr2+) √ √ √

NARS name

BL 3063e APR √

Bari Gom APR √

Misr 1 Sr2+Sr25 √ √ √ √ √

Misr 2 Sr25 √ √

Kavir Unknown

Bam Unknown √

V-04178 Unknown √

Flag 5m Unknown √ √

Stagnating

yield growth

Stagnating

investments in

agricultural R&D

Source: WDR 2008

Area planted and seed production obtained for Ug99 resistant

wheat genotypes during crop season 2008-09 in the six

countries (3 tons seed sent in 2008 from Mexico, )

Countries Area planted (ha) Seed produced

(Kg)

Nepal* 7.5 18386

Bangladesh* 7.0 12000

Afghanistan 2.0 9523

Egypt 21.1 81166

Ethiopia (summer

crop estimated)**

7.0 20000

Pakistan 9.0 23633

Total 52.6 162808* Incl. locally developed lines resistant to Ug 99; ** incl. 2 ICARDA derived lines

Provided adequate funds are available and

NARS and private companies agree and

do replace susceptible varieties

Thank You

Thank You