Differential impact of landscape-scale strategies for crop cultivar deployment on disease dynamics, resistance durability and long-term evolutionary control.

Julien Papaïx,Loup Rimbaud,Peter H Thrall,Jiasui Zhan,Jeremy J Burdon

doi:10.1111/eva.12570

Abstract

A multitude of resistance deployment strategies have been proposed to tackle the evolutionary potential of pathogens to overcome plant resistance. In particular, many landscape‐based strategies rely on the deployment of resistant and susceptible cultivars in an agricultural landscape as a mosaic. However, the design of such strategies is not easy as strategies targeting epidemiological or evolutionary outcomes may not be the same. Using a stochastic spatially explicit model, we studied the impact of landscape organization (as defined by the proportion of fields cultivated with a resistant cultivar and their spatial aggregation) and key pathogen life‐history traits on three measures of disease control. Our results show that short‐term epidemiological dynamics are optimized when landscapes are planted with a high proportion of the resistant cultivar in low aggregation. Importantly, the exact opposite situation is optimal for resistance durability. Finally, well‐mixed landscapes (balanced proportions with low aggregation) are optimal for long‐term evolutionary equilibrium (defined here as the level of long‐term pathogen adaptation). This work offers a perspective on the potential for contrasting effects of landscape organization on different goals of disease management and highlights the role of pathogen life history.

Highlights

The use of resistant crop cultivars against pathogens typically reduces epidemic development and associated yield losses in agricultural production systems
We found that the healthy area duration (HAD) of the susceptible cultivar increases with greater proportion of the resistant cultivar and lower spatial aggregation
To go beyond the blanket deployment of resistance genes, the sustainable management of crop resistance to disease needs a better understanding of the demogenetic dynamics of pathogen populations from the initial release of a new resistant cultivar to the breakdown/ erosion of its resistance and further adaptation of pathogen populations

Summary

Introduction

The use of resistant crop cultivars against pathogens typically reduces epidemic development and associated yield losses in agricultural production systems Such cultivars may rapidly become ineffective owing to the well-documented ability of pathogens to evolve and overcome plant resistance genes To maximize any advantages to be gained, such approaches should explicitly address and integrate epidemiological and evolutionary perspectives of pathogens (Thrall et al, 2011), noting that the definition of an optimal strategy may vary between different stakeholders for

Objectives

Findings

Conclusion