β-Aminobutyric Acid (BABA) Priming Enhances Yield Formation, Grain Filling, and Quality of Water-Stressed Ofada Rice (Oryza sativa L.)

Abstract

Drought stress remains a major constraint to rice production, particularly in sub-Saharan Africa where locally adapted varieties such as Ofada are highly susceptible to water deficits. This study investigated the potential of β-aminobutyric acid (BABA) as a priming agent to enhance drought tolerance, yield performance and grain quality in Ofada rice. Field experiment was setup in a split-plot complete randomized block design with drought imposed at vegetative, flowering and grain-filling stages under varying BABA treatments. Drought stress significantly reduced yield components, economic yield, and grain quality with the most pronounced effects observed at the flowering stage, confirming its critical sensitivity to water deficit. BABA application markedly improved percentage grain filling, panicle weight, grain weight per plant, and harvest index across stress conditions. These improvements were primarily driven by enhanced assimilate partitioning and sink strength rather than increase in total biomass. In addition, BABA treatment improved grain nutritional quality, as evidenced by increased carbohydrate, ash, and crude fat contents, indicating more efficient nutrient remobilization during grain development. The absence of consistent differences among BABA concentrations suggests the existence of a priming threshold, where low to moderate doses are sufficient to induce maximal physiological responses. Mechanistically, BABA-mediated improvements are associated with enhanced antioxidant capacity, modulation of abscisic acid-dependent signalling pathways, and optimized carbon and nitrogen metabolism. conclusively, the findings demonstrate that BABA-induced priming represents a viable, cost-effective, and environmentally sustainable strategy for enhancing drought resilience, stabilizing yield, and improving grain quality in Ofada rice, with important implications for climate-resilient rice production systems.