This research was conducted to study the incidence of seed-borne fungi in stored sunflower seeds under ambient conditions as well as their influence on seed viability and vigour. Certified seeds, Quality Declared Seeds (QDS) and Farmer saved seeds (FSS) were stored for six months. Seed samples were taken every month testing for fungal infection percent (FIP), germination percentage (G%) and seedling vigour index (SVI).
Eight fungal species namely as Aspergillus flavus, A. niger, Alternaria padwickii, A. zinniae, Botrytis cinerea, Curvularia lunata, Fusarium vericillioides and Rhizopus arrihizus were identified. At the end of experiment, the maximum species infection percentage were recorded on F. vericillioides (14.39), B. cinerea (14.28) in FSS and the minimum by A. zinniae (1.83) with QDS. Maximum total fungal infection incidence was recorded with FSS (73.11%) and minimum with QDS (66.94%) and certified seeds (67.06%). The QDS recorded the highest G% (81.56) and certified seeds (81.33%), the maximum SVI (96.76) was in certified seeds and 95.69 (in QDS). The minimum G% (60.67) and SVI (65.98) were found in FSS. The highest G% and SVI were recorded in seeds with minimum FIP. These results suggest that, fungal infections may negatively affect the seed viability and vigour. For the first time, the incidence of seed-borne fungi in stored sunflower seeds have been determined in Tanzania.