Screening buffelgrass (Cenchrus ciliaris) from selected pasture seed farms in Tanzania for seed-borne microorganism: pathogenicity and effect on germination

Masters Dissertation

Buffelgrass (Cenchrus ciliaris) is one of the important perennial grasses in the pasture industry in Tanzania. It is drought tolerant, nutritious and has rapid growth characteristics. Three hundred sixty grams of seed samples of C. ciliaris collected from six selected pasture seed farms were screened for seedborne microorganisms at the African Seed Health Centre, Sokoine University of Agriculture, Morogoro Tanzania. The Blotter method, the direct plating and the Top of Paper methods were used for fungal, bacterial and seed germination tests, respectively. Fungal and bacteria pathogens of economic importance that were detected included; Phoma spp (28.5 %), Curvularia lunata (17.34 %), Alternaria alternata (14.09 %) Bipolaris spp. (12.2 %), Acidovorax, Xanthomonas and Pseudomonas spp. Characterization using morphological and biochemical tests including molecular techniques and pathogenicity of fungal and bacteria strains were done on buffelgrass seedlings. Results indicated that seed germination decreased (<50%) with an increase in fungal infection. Seed samples from LITI Tengeru had the lowest seed germination (8 %) and high fungal (37.8 %) incidence on their caryopses. Pathogenicity of Bipolaris spp., Phoma spp., Pyricularia grisea, Fusarium pallidoroseum, Exserohilum rostratum, Nigrospora oryzae and Acidovorax, Pseudomonas and Xanthomonas bacterial strains were confirmed on C. ciliaris seedlings. Some species of the detected fungi were found in both spikelets and caryopses. Further research is needed on losses caused by fungal infection in buffelgrass seeds

Commission for Science Technology COSTECH