Optimizing boron and zinc application strategies to enhance seed yield and quality traits in finger millet (Eleusine coracana (L.) Gaertn.)

Abstract

Boron (B) and zinc (Zn) deficiencies are widespread in Indian soils, limiting both seed yield and quality in finger millet (Eleusine coracana L. Gaertn.). To address this, a two-year field study was conducted across two post-rainy seasons under semi-arid conditions. The experiment evaluated the effects of boron (B), zinc (Zn), B + Zn application along with absolute control (no micronutrient application) as foliar sprays at panicle initiation (PI), 50% flowering (FL), PI + FL and soil application (SA). The combined foliar application of B + Zn at PI and PI + FL stages consistently resulted in superior plant growth, reflected in increased plant height, number of productive tillers, and ear dry weight. It significantly outperformed individual nutrient treatments and the control. This treatment also recorded the highest seed and stover yields, harvest index, and improved seed quality traits such as germination, field emergence, and seedling vigor indices. Foliar feeding proved more effective than soil application, with sprays during early reproductive stages delivering the most pronounced benefits. However, economic analysis based on the benefit-cost (BC) ratio revealed that zinc applied alone at PI and PI + FL stages offered greater profitability compared to combined nutrient applications. This suggests that while B + Zn foliar sprays optimize biological performance, zinc-alone treatments are more cost-efficient. Overall, the findings underscore that synchronizing foliar applications of boron and zinc at key growth stages is a practical and scalable strategy to enhance seed yield potential and seed vigor in finger millet under semi-arid, micronutrient-deficient conditions.