Study on seed health status of sunflower in Bangladesh.
The seed health status of 2 cultivars of sunflower (Kironi and local) was studied. A total of 3518 seedborne fungal infections were recorded in 8000 seeds of the 2 cultivars collected from various locations in Bangladesh. The fungi were detected by blotter method. The 9 species of fungi recorded, in order of prevalence, were Alternaria alternata, Botrytis cinerea, Rhizopus stolonifer, Fusarium moniliforme [Gibberella moniliformis], Fusarium semitectum [F. pallidoroseum], Aspergillus niger, Penicillium sp., Aspergillus flavus and Curvularia lunata [Cochliobolus lunatus]. Of all these fungi, A. alternata, B. cinerea, F. moniliforme, F. semitectum and R. stolonifer were predominant. The 9 fungi detected in sunflower seeds appeared to be new records for Bangladesh. The prevalence of total and individual seedborne fungal infections varied significantly with respect to the cultivar and location. Seed germination also varied significantly depending on the cultivar and seed source. All the 5 fungi were pathogenic. A. alternata induced characteristic leaf spot and blight symptoms on inoculated leaves. B. cinerea and R. stolonifer caused gray mould blight and head rot symptoms, respectively. F. moniliforme and F. semitectum resulted in seed rot or germination failure, pre- and post-emergence death, and foot/root rot to sunflower seedlings.