Inside the global effort to defend rice from major diseases 

By Van Schepler-Luu & Myrtel Anne Valenzuela

Rice diseases such as bacterial blight and blast are no strangers to farmers across Asia and Africa. Year after year, these fast-evolving threats reduce yields, undermine farmer livelihoods, and chip away at food security. However, scientists are staying one step ahead of these diseases through near-isogenic lines (NILs).

Near-isogenic lines are highly specialized rice lines that carry a unique resistance gene within an otherwise uniform background. Physically, they look just like any other rice plant, but this subtle genetic difference gives researchers a powerful way to study how these NILs respond to pathogens, and more importantly, how to breed stronger, more resilient rice varieties.

For over four decades, NILs have played a key role in breeding disease-resistant rice. The IRBB (bacterial blight) and IRBL (blast) lines, developed through a long-standing collaboration between the International Rice Research Institute (IRRI) and the Japan International Research Center for Agricultural Sciences (JIRCAS), have become global standards for studying rice diseases. From 2012 to 2025, over 1,100 samples were distributed to 26 institutions in 14 countries, which highlights their lasting impact on rice research and crop protection.