Development of Novel, Durable Wheat Blast Resistance via X-ray Induced Mutation Breeding

Abstract

Wheat blast, caused by the fungus Magnaporthe oryzae Triticum (MoT), poses a severe and escalating threat to global food security, particularly as conventional breeding struggles due to scarce genetic resources and the pathogen’s rapid adaptation. In this study, X-ray irradiation-induced mutation breeding was employed to develop novel and durable resistance. Seeds of three high-yielding wheat varieties from Bangladesh: BARI Gom 27 (BG27), BARI Gom 29 (BG29), and BARI Gom 33 (BG33), were treated with a single acute dose of 180 Gy. Following irradiation, preliminary screening of the M2 generation using a Detached Leaf Assay (DLA) identified thirty fully resistant lines. To assess the stability and durability of resistance, fourteen selected M2 lines were advanced to the M3 generation and subject to rigorous field screening under artificial MoT inoculation in a blast-endemic environment. This critical field evaluation identified eight superior mutant lines, including BG27(X180)-8-4, BG27(X180)-8-5, and four lines derived from the BG33(X180)-98 series, all of which exhibited complete immunity (0% disease incidence and 0% disease severity) to MoT. To the best of our knowledge, this is the first report of completely blast-resistant M3 wheat lines identified through large-scale, open-field screening using X-ray induced mutagenesis of three high-yielding varieties. These resistant M3 lines represent an invaluable and readily deployable genetic resource for the rapid development of durable, blastresistant wheat cultivars. Such advancements are crucial for mitigating the growing threat of wheat blast in high-risk regions, including Bangladesh, Zambia, and parts of South America. A further multi-location field trials and genomic analyses of the mutant lines are essential to ensure their stability for deployment as blast-resistant wheat variety, and identify the loss-of-function mutation(s) useful for marker development for molecular breeding.

J. Bangladesh Acad. Sci. 50(1); 35-50: March 2026