Department of Plant Sciences, University of Cambridge, Cambridge CB2 1TN, UK.
J R Soc Interface. 2022 Oct;19(195):20220517. doi: 10.1098/rsif.2022.0517. Epub 2022 Oct 19.
Population-scale effects of resistant or tolerant crop varieties have received little consideration from epidemiologists. When growers deploy tolerant crop, population-scale disease pressures are often unaffected. This only benefits growers using tolerant varieties, selfishly decreasing yields for others. However, resistant crop can reduce disease pressure for all. We coupled an epidemiological model with game theory to understand how this affects uptake of control. Each time a grower plants a new crop, they must decide whether to use an improved (i.e. tolerant/resistant) or unimproved variety. This decision is based on strategic-adaptive expectations in our model, with growers comparing last season's profit with an estimate of what is expected from the alternative crop. Despite the positive feedback loop promoting use of a tolerant variety whenever it is available, a mixed unimproved- and tolerant-crop equilibrium can persist. Tolerant crop can also induce bistability between a scenario in which all growers use tolerant crop and the disease-free equilibrium, where no growers do. However, due to 'free-riding' by growers of unimproved crop, resistant crop nearly always exists in a mixed equilibrium. This work highlights how growers respond to contrasting incentives caused by tolerant and resistant varieties, and the distinct effects on yields and population-scale deployment.
耐病或耐除草剂作物品种的大规模效应在很大程度上尚未引起流行病学家的重视。当种植者采用耐病品种时，往往不会对大规模的疾病压力产生影响。这仅有利于使用耐病品种的种植者，自私地降低了其他种植者的产量。然而，抗病作物可以减轻所有人的疾病压力。我们将流行病学模型与博弈论相结合，以了解这如何影响控制措施的采用。每次种植者种植新作物时，他们必须决定是使用改良（即耐病/抗病）品种还是非改良品种。该决策基于我们模型中的策略自适应预期，种植者将上一季的利润与对替代作物的预期进行比较。尽管存在促进在任何可用时使用耐病品种的正反馈循环，但未改良品种和耐病品种的混合均衡仍可能持续存在。耐病品种也会在所有种植者使用耐病品种的情况下以及无病均衡（即没有种植者使用）之间引起双稳态。然而，由于未改良作物种植者的“搭便车”行为，抗病作物几乎总是存在于混合均衡中。这项工作强调了种植者如何应对耐病和抗病品种带来的截然不同的激励措施，以及它们对产量和大规模部署的不同影响。
