Carbon Ion Beam-Induced Mutagenesis for the Development of Durable Blast- Resistant Wheat Mutant Lines with High-Yield Potential

Wheat blast, caused by Magnaporthe oryzae pathotype Triticum (MoT), is a catastrophic threat to global food security. Given the narrow genetic base of resistance in current elite germplasm, this study evaluated heavy ion beam irradiation as a novel physical mutagenic approach to develop durable blast-resistant wheat lines from two popular varieties, BARI Gom 28 and BARI Gom 30. Seeds were exposed to carbon ion beam doses of 50, 60, and 70 Gy, resulting in total 772 surviving M1 plants. High-throughput screening of M2 progenies via detached leaf assay identified 80 resistant lines, which were further narrowed to 16 promising mutants through artificial inoculation in the M3 generation. Notably, the mutant line BG30(I60)-77-8-3 exhibited immune-level resistance (0% severity), while others-maintained severity below 6.3%, compared to over 70% in parental controls. Beyond resistance, these mutants showed superior agronomic performance; BG28(60)-42-10-3 achieved a twofold yield increase over its parent, supported by a significant rise in effective tillers (25 vs. 11). Principal Component Analysis confirmed that carbon ion beam irradiation effectively decoupled disease susceptibility from yield traits, with moderate doses (50–60 Gy) proving optimal for balancing mutational frequency with plant survival. Their high field resistance and enhanced yield potential make them primary candidates for direct varietal release or as donor parents in speed breeding programs. Taken together, our study demonstrates that carbon ion beam irradiation is an effective tool for developing high-yielding, blast-resistant wheat mutant lines suitable for further breeding and varietal development.