Effect of Sources and Storage Conditions on Quality of Sorghum Seeds
A study was conducted in three agro-ecological zones of Tanzania to investigate sources, status, quality and storage conditions of sorghum ( Sorghum bicolor L.) seeds. Sorghum seed samples were collected from Kwimba (Lake zone), Chamwino (Central zone) and Kilosa (Eastern zone) districts. In surveyed districts 83.3 % of farmers were using farmer saved seeds while 16.7 % were using improved sorghum seeds. In surveyed areas, 85 % of seed samples were obtained from small scale farmers as farmer saved seeds, 1.7% from seed stockists and 13.3% from agriculture research institutions. Seeds were found stored in the households (86.7%) and in go-down in case of seeds stockists (13.3%). The laboratory purity analysis test results indicated that Kwimba had pure seeds of 94.4%, Chamwino 96.5% and Kilosa 99.0%. Inert matters; Kwimba 5.3%, Chamwino 1.8% and Kilosa 1.0%. The non-sorghum seeds observed were Kwimba 0.2%, Chamwino 1.8% and Kilosa 0%. The results were significantly different at P<0.001 from one agro-ecological zones to another. The germination test of sorghum seeds varied highly significantly (P<0.001) from Kwimba 74%, Chamwino 88% and Kilosa 85%. Seed-borne fungal species found in the samples from the study areas were Fusarium moniliforme, Bipolaris sorghicola, Curvularia lunata, Colletotrichum graminicola and Phoma sorghina . Samples collected from Eastern zone had the highest infection by fungi. Other pathogens Aspergillus flavus, A. niger, Penicillium spp., Claviceps spp. and Rhizopus spp . were found infecting seeds. Central agro-ecological zone is proposed to be better for sorghum seeds production for healthier seeds due to non-fungal infection observed in this study. Key words : agro-ecological zones, seed, moisture content, purity, germination, seed-borne pathogens