Fig. 1. Evolutionary rescue following a continental outbreak of a sorghum pest.

(A) Infestation of SCA, M. sacchari, on a commercial hybrid in the U.S. sorghum-growing production region (Kansas). (B) SCA infestation on a traditional sorghum variety on a smallholder farm in Haiti (brown plant in foreground; green leaves in background are maize and wild grasses). (C) Reaction of susceptible (brown plants; foreground) and resistant (green plants; background) sorghum breeding lines under natural SCA infestation during breeding trials in Haiti. (D) Estimates of annual sorghum production in Haiti (2006–2019) indicating the start of the SCA outbreak (1, red arrow) and the start of national distribution of SCA-resistant variety, Papèpichon (2, blue arrow). (E) Genome-wide nucleotide diversity (π) in the HBP (red line) compared to a global diversity panel (GDP; blue bars). Nucleotide diversity was calculated for a nonoverlapping sliding window of 1 Mbp across the genome. The gray vertical dashed lines indicate the position of a priori candidate genes for breeding targets of the Haiti program, which colocalized with genomic regions of reduced π (see file S3 for details). Photo credit: (A and B) Geoffrey Morris, Colorado State University; (C) Gael Pressoir, University of Quisqueya.