In vitro mutagenesis for the identification of blast-resistant rice (Oryza sativa L.) genotypes

Abstract

Rice blast disease causes 10–30% annual yield losses globally, necessitating the rapid development of resistant cultivars with maintained agronomic performance. In this study, EMS-induced callus mutagenesis integrated with hyperspectral phenotyping and molecular marker screening to rapidly generate blast-resistant variants from the susceptible BRRI dhan28. Optimized mutagenesis (0.5 mM EMS) produced S₃ putative somaclones exhibiting substantial genetic diversity. Screening against virulent Pyricularia oryzae isolates identified four moderately resistant lines that achieved 68–72% yield increases (16.81–17.27 g hill−1) compared to the susceptible parent (10.03  g hill−1). Molecular profiling detected multi-allele resistance carriers, including line EMS 0.5–3 harboring Pib, Pik-p, and Piz-t genes, while novel hyperspectral-PCA protocols enabled objective, non-destructive disease quantification, resolving a major phenotyping bottleneck in mutation breeding. Overall, this work presents the first integration of in vitro chemical mutagenesis with precision phenomics for rice blast resistance, providing deployable germplasm, validated high-throughput screening pipelines, and a scalable framework for accelerated crop improvement under climate-resilient agriculture.