PANCRIN, a prototype model of the pandemic cultivar‐race interaction of yellow rust on wheat in China

The pandemic of yellow rust on wheat in China, including cultivar‐race interactions at the population level, is described by a prototype model (PANCRIN). As the framework of this model, the main epidemic system of wheat yellow rust in China was divided into 11 epidemiological regions. The major parameters are R, the rate of epidemic progress of each region in each month, determined by regional climatological factors and cultivar‐race interactions; DIL, the dilution coefficient of inter‐regional longdistance dissemination of this disease, determined mainly by distance; and F, fitness values of the pathogen on different cultivar‐race combinations. With cultivar deployment, initial disease amount, and initial race frequency as inputs, this model can output the disease amount on each cultivar and the race frequencies of each region. Results of preliminary simulation experiments tallied with some historical situations such as the breakdown of disease resistance of some important cultivars Weak points of this model are also discussed.