Effect of Sources and Storage Conditions on Quality of Sorghum Seeds

Abstract

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