Mutagenic effectiveness and efficiency of gamma rays on variability for yield attributing traits in Fonio (Digitaria exilis [Kippist] Stapf.)

A study was conducted to determine the mutagenic effectiveness and efficiency of different doses of gamma rays in inducing variability that could be exploited in the genetic improvement of fonio. Seeds of five accessions of fonio were irradiated with five different doses of gamma rays (100 Gy, 200 Gy, 400 Gy, 500 Gy and 0 Gy as control). The seeds were sown in a plot in a completely randomized design with three replications to rise the M1 generation which was advanced to M2 generation. The result obtained from the M2 mutants revealed highly significant difference (P≤0.01) in the effects of different gamma rays doses on the growth and yield traits of fonio. This implies the presence of high genetic variability induced by the mutagen in fonio. The effect is concentration dependent, increase with decrease in irradiation dose. More so, the effectiveness of the mutagen decreases with increase in dose. Seven different chlorophyll deficient mutants were found in the form of: Albina, Chlorina, Lustescent, Striata, Viridis, Viriscent and Xantha, with Xantha, Chlorina and Albina as the most frequent chimeras, The result indicated that lower dose of gamma rays (100 Gy) is more effective and efficient as it induces favorable mutation that could be utilized in the genetic improvement of fonio. Accession Nkpowas was found to respond more to the mutagenic treatment. Keywords: Accessions, Fonio, Gamma Rays, Mutation

Antimicrobial studies on the stem-bark extracts of Ficus kamerunensis Warb.

Ficus kamerunensis is an epiphytic shrub or tree growing up to 20 m high. The plant is used in ethnomedicine to treat microbial infections of different kinds. Antimicrobial activity of methanol extract of the stem-bark of Ficus kamerunensis and fractions of the same (ethyl acetate, diethyl ether, n-butanol, aqueous) was studied. Agar diffusion method was used to screen the extracts while minimum inhibitory concentrations (MICs) of the extracts were determined at 0.5 scale Mc-farland’s turbidity standard and with standard ciprofloxacin as positive control. The diameter of zone of inhibition of the extracts against test microorganisms (in mm) was highest for the ethyl acetate, followed by diethyl ether then n-butanol extracts while the least was with the methanol extract. The zones of inhibition of the extracts were in the range of 18-31 mm. The MIC and MBC for the extracts were 6.25 mg/ml and 12.5 mg/ml respectively. Antimicrobial evaluation shows that the extracts have activity against E. coli, Candida albicans, Candida stellatodea, Corynebacterium ulcerans, MRSA, Neisseria gonorrheae, Pseudomonas aeruginosa Staphylococcus aureus while Candida tropicalis, Candida krusei, Proteus mirabilis and Streptococcus pyrogens were resistant. This therefore, supports the ethnomedical usage of the plant for the treatment of infectious diseases.Keywords: Ficus kamerunensis, Antimicrobial, MIC and MBC/ MF