Fetien Abay

Network analysis of barley seed flows in Tigray, Ethiopia: supporting the design of strategies that contribute to on-farm management of plant genetic resources

For maintaining food security and livelihood, farmers in marginal areas of production environments make use of high levels of crop genetic diversity. The exchange of seed and varieties among villagers, and also the relative isolation of local varieties in their production environments, contributes to the continued existence of locally adapted genotypes. In Tigray, one of the major barley-growing regions of Ethiopia, local varieties and local seed systems are dominant. The annual barley seed requirement is met with seed produced, saved and exchanged by farmers. In order to understand the flows of seed and varieties within and between villages, a study was conducted using a survey to gather information from 130 respondents in seven villages. Seed network analysis was used as an analytical tool to assess flows of seed and varieties and to identify farmers who play different roles in the seed system. Within the major seed exchange network, nodal or connector farmers linked seed subnetworks. The flow within villages was much more dominant than beyond. Rare varieties appeared to be sourced from farms that maintain a broad variety portfolio. Varieties seemed to disseminate informally across farms, in their target environments, following participatory varietal selection. The methodology of social seed network analysis proved to be a powerful tool for monitoring seed and variety flows. Furthermore, it identified farmers as critical partners in the conservation and on-farm management of plant genetic resources, recognized the role of plant breeders in participatory varietal selection and that of seed experts, engaged in strengthening local seed supply and in disseminating quality seed of superior varieties.

Effect of integrated soil bunds on key soil properties and soil carbon stock in semi-arid areas of northern Ethiopia

Land degradation is a serious global problem. To reclaim degraded land, many soil bunds have been implemented. However, their effectiveness has not been studied in all regions of Ethiopia. The objective of this study was to investigate the effect of soil bunds integrated with tree fodder species on selected soil properties and carbon stock in semi-arid areas of northern Ethiopia. Twenty-seven composite soil samples were collected from 20 cm depth. The soil parameters texture, soil organic matter (SOM), total nitrogen (TN), pH, cation exchange capacity (CEC), available phosphorus (Av.P) and available potassium (Av.K) were analysed. Statistical analyses were performed using one-way ANOVA and mean comparisons were made using Tukey’s honestly significant difference test. Mean values of SOM (2.13%, 1.47% and 0.85%), CEC (150.42, 100.58 and 80.68 cmol kg−1 soil), TN (0.2, 0.14 and 0.08%), Av.P (7.08, 6.03 and 4.36 ppm), Av.K (1.52, 1.34 and 1.27 cmol kg−1 soil), soil carbon stock (SCS; 12.48, 10.47 and 4.7 t ha−1) and soil bulk density (BD; 1.35, 1.43 and 1.44 g m−3) were recorded in soil bunds integrated with forage species (ISB), soil bunds alone (SB) and non-conserved cultivated land (NC), respectively. The BD, SOM, CEC, TN and SCS showed a significant difference among the three cropland treatments and Av.P showed a significant difference only between (ISB and SB) and NC. The pH showed no significant differences and Av.K showed no significant difference between SB and NC. The findings indicate that integrating soil bunds with forage species was a better option to improve soil properties than soil bunds alone.

Biochemical and molecular identification and characterization of lactic acid bacteria and yeasts isolated from Ethiopian naturally fermented buttermilk

Lactic acid bacteria (LAB) and yeasts were enumerated and identified from naturally fermented buttermilk. Isolates were first subjected to chemical tests and then to molecular characterization. Molecular identification involved pure sequencing of 16s rRNA (LAB) and 18s rRNA (yeast) genes. Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (DGGE) was used for detection of microbiota composition. Eighty-five LAB and 26 yeast isolates obtained from 16 small-scale dairy farms were isolated and identified. The microbial composition was dominated by strains of Lactococcus lactis ssp. lactis, Lactobacillus plantarum and Saccharomyces cerevisiae. Molecular techniques enabled not only genetic confirmation but also detection of some uncultivated strains. The presence of diverse strains of LAB and yeasts in NFB indicated a potential for development of different starter cultures to make new dairy products.

Chemical composition of naturally fermented buttermilk

Naturally fermented buttermilk, prepared from soured cream or milk, was collected during two seasons from sixteen farms in northern Ethiopia, to study chemical composition and flavour compounds. Protein, fat, organic acids, carbohydrates and volatile compounds were quantified using Kjeldahl, Gerber, high-pressure liquid chromatography (HPLC) and headspace GC methods, respectively. Widely differing concentrations of organic acids and volatile compounds among samples indicated variable fermentation in the products. This indicates the need for the introduction of the standardisation of the process to supply the market with homogenous buttermilk products.