Priming with botanical leaf extracts enhances emergence and vigour in soybean (Glycine max)

Abstract

Soybean (Glycine max L.) is a vital legume crop that is widely cultivated for its high protein and oil contents and serves as an essential food and industrial resource. In Ghana, efforts to improve soybean productivity have largely focused on synthetic seed treatments, despite the growing interest in sustainable agricultural practices. This study aimed to evaluate the effectiveness of seed priming using botanical leaf extracts, namely those of moringa (Moringa oleifera), neem (Azadirachta indica), and tithonia (Tithonia diversifolia), on the growth and physiological seed quality after harvest of three soybean varieties (‘Afayak’, ‘Jenguma’, and ‘Favour’). We hypothesised that botanical priming would enhance seed and plant performance compared to non-primed controls. A 3 × 4 factorial experiment was conducted using a randomised complete block design. Measurable results showed that seeds primed with 10% moringa and neem leaf extracts significantly increased the plant height, number of branches, 1000-seed weight, and seed vigour, with electrical conductivity values ranging from 17 to 34 µS cm⁻¹g⁻¹, which is within the recommended range for high seed vigour. The germination percentage after harvest remained consistently high across treatments (80–95%), with no significant delays in flowering time. Moringa-primed Afayak seeds had the highest 1000-seed weight (110.36 g), and tithonia-primed seeds showed reduced performance and higher fungal incidence. These results confirm the hypothesis and highlight the potential of botanical priming as an effective, low-cost strategy for improving soybean seed quality and crop establishment. These findings offer practical implications for sustainable agriculture in sub-Saharan Africa, promoting environmentally friendly alternatives to synthetic agrochemicals.