Modulation of germination traits in selected cereal and legume crops by seed aging and capsicum treatment

This study investigates the effects of capsaicin, a natural alkaloid in Capsicum species, on the seed storage biology of five crops: barley (Hordeum vulgare L.), common bean (Phaseolus vulgaris L.), maize (Zea mays L.), cowpea (Vigna unguiculata L.), and wheat (Triticum aestivum L.). Seeds were treated with 0.18% capsaicin and stored for 1, 4, and 7 years under ambient conditions. Post-storage germination parameters, including germination percentage, speed, and mean germination time, were evaluated. Results revealed species-specific responses: cowpea and wheat showed higher germination, up to 68% and 69%, with faster germination after 4 and 7 years. Barley and common bean exhibited reduced germination, as low as 0.75% and 18%. Maize responses were variable and generally low, likely due to initial seed quality rather than capsaicin. These findings suggest capsaicin may act differently depending on species physiology and seed quality and may serve as a natural bioregulator to enhance seed longevity in sensitive species. This study is among the first to evaluate capsaicin vapour as a biostimulant for long-term seed storage, providing insights for seed banks and plant genetic resource conservation.