title: Research investment implications of shifts in the global geography of wheat stripe rust.
abstract: Breeding new crop varieties with resistance to the biotic stresses that undermine crop yields is tantamount to increasing the amount and quality of biological capital in agriculture. However, the success of genes that confer resistance to pests induces a co-evolutionary response that depreciates the biological capital embodied in the crop, as pests evolve the capacity to overcome the crop's new defences. Thus, simply maintaining this biological capital, and the beneficial production and economic outcomes it bestows, requires continual reinvestment in new crop defences. Here we use observed and modelled data on stripe rust occurrence to gauge changes in the geographic spread of the disease over recent decades. We document a significant increase in the spread of stripe rust since 1960, with 88% of the world's wheat production now susceptible to infection. Using a probabilistic Monte Carlo simulation model we estimate that 5.47 million tonnes of wheat are lost to the pathogen each year, equivalent to a loss of US$979 million per year. Comparing the cost of developing stripe-rust-resistant varieties of wheat with the cost of stripe-rust-induced yield losses, we estimate that a sustained annual research investment of at least US$32 million into stripe rust resistance is economically justified.
authors.affiliation: International Science and Technology Practice and Policy (InSTePP) Center in the Department of Applied Economics at the University of Minnesota, 1994 Buford Ave, 248 Ruttan Hall, Saint Paul, Minnesota 55108, USA.|Stakman-Bourlaug Cereal Rust Center at the University of Minnesota, 495 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, Minnesota 55108, USA.|Commonwealth Scientific and Industrial Research Organization (CSIRO), GPO Box 1700, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Beddow
authors.affiliation: International Science and Technology Practice and Policy (InSTePP) Center in the Department of Applied Economics at the University of Minnesota, 1994 Buford Ave, 248 Ruttan Hall, Saint Paul, Minnesota 55108, USA.|Stakman-Bourlaug Cereal Rust Center at the University of Minnesota, 495 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, Minnesota 55108, USA.|Commonwealth Scientific and Industrial Research Organization (CSIRO), GPO Box 1700, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Philip G
authors.initials: PG
authors.lastname: Pardey
authors.affiliation: International Science and Technology Practice and Policy (InSTePP) Center in the Department of Applied Economics at the University of Minnesota, 1994 Buford Ave, 248 Ruttan Hall, Saint Paul, Minnesota 55108, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Chai
authors.affiliation: International Science and Technology Practice and Policy (InSTePP) Center in the Department of Applied Economics at the University of Minnesota, 1994 Buford Ave, 248 Ruttan Hall, Saint Paul, Minnesota 55108, USA.|Stakman-Bourlaug Cereal Rust Center at the University of Minnesota, 495 Borlaug Hall, 1991 Upper Buford Circle, Saint Paul, Minnesota 55108, USA.|Commonwealth Scientific and Industrial Research Organization (CSIRO), GPO Box 1700, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Terrance M
authors.initials: TM
authors.lastname: Hurley
authors.affiliation: International Science and Technology Practice and Policy (InSTePP) Center in the Department of Applied Economics at the University of Minnesota, 1994 Buford Ave, 248 Ruttan Hall, Saint Paul, Minnesota 55108, USA.|Commonwealth Scientific and Industrial Research Organization (CSIRO), GPO Box 1700, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Darren J
authors.identifier: http://orcid.org/0000-0003-2599-8105
authors.initials: DJ
authors.lastname: Kriticos
authors.affiliation: International Maize and Wheat Improvement Center (CIMMYT), El Batán, Texcoco, Edo. de México 56237, Mexico.
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Braun
authors.affiliation: Plant Breeding Institute at the University of Sydney, Private Bag 4011, Narellan, New South Wales 2567, Sydney, Australia.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Park
authors.affiliation: New South Wales Department of Primary Industries, NSW DPI, Locked Bag 21, Orange, New South Wales 2800, Australia.
authors.forename: William S
authors.initials: WS
authors.lastname: Cuddy
authors.affiliation: International Science and Technology Practice and Policy (InSTePP) Center in the Department of Applied Economics at the University of Minnesota, 1994 Buford Ave, 248 Ruttan Hall, Saint Paul, Minnesota 55108, USA.|Commonwealth Scientific and Industrial Research Organization (CSIRO), GPO Box 1700, Canberra, Australian Capital Territory, 2601, Australia.
authors.forename: Tania
authors.initials: T
authors.lastname: Yonow