Temporal dynamics of wheat blast caused by Pyricularia oryzae Triticum lineage throughout the successive wheat cycles

Abstract

Abstract Wheat blast, caused by Pyricularia oryzae Triticum lineage (PoTl), can infect wheat leaves and heads. The pathogen biology and disease epidemiology of the isolates PoTl still need more profound insights for the integrated management of wheat blast in Brazilian wheat fields. This study aimed to characterize the incubation period, latent period, and the temporal progress of wheat blast and to fit the best nonlinear model, describing the nature of an epidemic of the PoTl isolate 12.1.146 compared with the PoTl isolate Py6038, throughout five successive infection cycles of PoTl on wheat leaves and heads. Wheat blast occurred in all infection cycles. The incubation period and latent period of the PoTl isolate 12.1.146 were significantly shorter than that of the PoTl isolate Py6038. The secondary inocula produced by the PoTl isolates on symptomatic wheat leaves caused blast symptoms when inoculated on wheat heads. The area under the disease progress curve (AUDPC) was calculated based on disease severity. In all infection cycles, the AUDPC of the PoTl isolate 12.1.146 was significantly higher than that of the PoTl isolate Py6038. The nonlinear logistic model had the best fit to describe the intensity of the disease progress curves (DPCs) of PoTl isolates on wheat leaves and heads, fitting classic sigmoid-shaped curves. Our findings show that the disease severity of the PoTl isolate 12.1.146 did not reduce under grow chamber conditions, even after five successive infection cycles. These findings may imply the integrated management of the disease wheat blast pathogen in Brazilian fields.