Sorghum Seed Health Management: Implications of Legume Intercropping for Seed-borne Fungal Pathogens, Seed Quality and Longevity

Abstract

Sorghum (Sorghum bicolor (L.) Moench) is an important staple crop for food security, income generation, and livelihoods, especially in the semi-arid regions of sub-Saharan Africa. However, seed-borne fungal diseases pose a significant constraint to sorghum productivity by affecting germination, seed vigour, seedling establishment, grain quality, and storage longevity. This review synthesises existing knowledge on sorghum seed health and seed-borne fungal pathogens, and the potential role of sorghum–legume intercropping in influencing fungal infection, seed quality, and storability. Important seed-associated fungi, including Fusarium, Alternaria, Curvularia, Aspergillus, Penicillium, and Colletotrichum, have been reported in sorghum and are associated with reduced seed viability, seedling establishment, grain deterioration during storage, and potential mycotoxin contamination. Sorghum–legume intercropping contributes to seed health management by disrupting continuous host cropping, altering the crop microclimate, enhancing soil fertility, and modifying beneficial microbial communities. However, a thick intercrop canopy could also increase humidity and thus favour fungal growth in certain environments. Although evidence for agronomic services of intercropping is growing, there is a paucity of literature relating specific legume species to seed-borne fungal infection, seed vigour, and storage longevity, especially in the semi-arid region of East Africa. Future research should integrate field-based disease assessment, pathogen identification and characterisation, seed quality testing, and storage studies to elucidate these interactions for sustainable sorghum seed health management.