, a Novel Wheat Blast Resistance Gene Derived from .

Wheat blast, caused by (syn. ) pathotype (MoT), is a devastating disease that can result in up to 100% yield loss in affected fields. To find new resistance genes against wheat blast, we screened 199 accessions of , the D genome progenitor of common wheat (), by seedling inoculation assays with Brazilian MoT isolate Br48 and found 14 resistant accessions. A synthetic hexaploid wheat line (Ldn/KU-2097) derived from a cross between the 'Langdon' (Ldn) and resistant accession KU-2097 exhibited resistance in seedlings and spikes against Br48. In an F population derived from 'Chinese Spring' × Ldn/KU-2097, resistant and susceptible individuals segregated in a 3:1 ratio, suggesting that the resistance from KU-2097 is controlled by a single dominant gene. We designated this gene . Genetic mapping using an F population from the same cross mapped the locus to the short arm of chromosome 2D. was ineffective against Bangladesh isolates but effective against Brazilian isolates. Field tests in Bolivia showed increased spike resistance in a synthetic octaploid wheat line produced from a cross between common wheat cultivar 'Gladius' and KU-2097. These results suggest that would be beneficial in farmers' fields in South America.