Elevational changes in vascular plants richness, diversity, and distribution pattern in Abune Yosef mountain range, Northern Ethiopia

The aim of this research is to investigate the patterns of vascular plant species richness,diversity,and distribution along an elevation gradient in the Abune Yosef mountain range,Ethiopia.Preferential systematic sampling was employed to collect vegetation and environmental data along the elevation gradient.We found that plant species richness declines monotonically from low to high elevations.Specifically,vascular plant species richness and diversity were lower in the Afroalpine grassland(high elevation)than in the Dry evergreen Afromontane forest and Ericaceous forest(low elevations).In contrast,endemic vascular plant richness was significantly higher in the Afroalpine grassland than in the Dry evergreen Afromontane forest and Ericaceous forest.Elevation showed a significant impact on the richness,diversity,and endemism of vascular plants.According to Sorensen's coefficient,the similarity between Dry evergreen Afromontane forest and Ericaceous forest vegetation types is higher(32%)than the similarity between Ericaceous forest and Afroalpine grassland(18%).Only 5%similarity was recorded between the Dry evergreen Afromontane forest and Afroalpine grassland.Growth forms showed different elevationai richness patterns.Trees and liana increased monotonically up to 3300 m.Shrub and herb richness patterns followed a hump-shaped and inverted hump-shaped pattern along the elevation gradient.The elevation patterns of vascular plant species richness,diversity,and growth form in the present study may be attributed to differences in management intensity,spatial heterogeneity,microclimatic variations,and anthropogenic disturbances.

Yield stability and relationships among stability parameters in faba bean(Vicia faba L.) genotypes

Sixteen faba bean genotypes were evaluated in 13 environments in Ethiopia during the main cropping season for three years(2009–2011). The objectives of the study were to evaluate the yield stability of the genotypes and the relative importance of different stability parameters for improving selection in faba bean. The study was conducted using a randomized complete block design with four replications. G × E interaction and yield stability were estimated using 17 different stability parameters. Pooled analysis of variance for grain yield showed that the main effects of both genotypes and environments, and the interaction effect, were highly significant(P ≤ 0.001) and(P ≤ 0.01), respectively. The environment main effect accounted for 89.27% of the total yield variation, whereas genotype and G × E interaction effects accounted for 2.12% and 3.31%, respectively.Genotypic superiority index(Pi) and FT3 were found to be very informative for selecting both high-yielding and stable faba bean genotypes. Twelve of the 17 stability parameters,including CVi, RS, α, λ, S2 di, bi, S(2)i, Wi, σ2i, EV, P59, and ASV, were influenced simultaneously by both yield and stability. They should accordingly be used as complementary criteria to select genotypes with high yield and stability. Although none of the varieties showed consistently superior performance across all environments, the genotype EK 01024-1-2ranked in the top third of the test entries in 61.5% of the test environments and was identified as the most stable genotype, with type I stability. EK 01024-1-2 also showed a17.0% seed size advantage over the standard varieties and was released as a new variety in2013 for wide production and named "Gora". Different stability parameters explained genotypic performance differently, irrespective of yield performance. It was accordingly concluded that assessment of G × E interaction and yield stability should not be based on a single or a few stability parameters but rather on a combination of stability parameters.

Hygienic Production Practices and Microbial Quality of Cow Milk in Cheha District of Gurage Zone, Southern Ethiopia

The aim of the study was to assess hygienic production practices and to evaluate microbial quality of raw cows’ milk in Cheha district of Gurage Zone, Southern Ethiopia. The study was conducted by interviewing 180 smallholder milk producers from two agro-ecologies (highland and midland) and by collecting 40 milk samples from milk producers, small shops, cafes and consumers for microbial quality analysis. The result indicated that majority of the respondents (96.7%) did not have cow barn and milking area, 57.3% of them clean their barn once and more than once a week. Moreover, milking without hand washing, absence of udder washing, failure to use towel to clean the udder, and use of plastic pail as milking equipment were practiced by 33.9%, 52.2%, 74.4% and 95.6% of the respondents, respectively. Furthermore, higher number of respondents (69.4%) used river water without proper treatment as a major source of water for cleaning purpose and majority of them fail to regularly clean utensils with detergents. Concerning microbial quality, overall mean total bacterial counts (TBC), Coliform counts (CC) and pH values of milk from current finding were 5.675 ± 0.016, 4.414 ± 0.017 log10 cfu/ml, and 5.963 ± 0.081, respectively. In general, overall quality of milk produced as well as marketed in the study area was poor. These were justified from poor hygienic practices and high values of TBC and CC that were significantly higher than the acceptable limits set by Ethiopian Standards for unpasteurized milk. Therefore, adequate sanitary and control measures should be taken at all stages from production to consumer level to produce and supply wholesome milk.

Grain yield stability analysis using parametric and nonparametric statistics in oat(Avena sativa L.)genotypes in Ethiopia

Background:The performance of oat genotypes differs across environments due to variations in biotic and abiotic factors.Thus,evaluation of oat genotypes across diverse environments is very important to identify superior and stable genotypes for yield improvement.Methods:The study aimed to assess the interaction(genotype-by-environment interaction;GEI)effect and determine the stability of grain yield in oat(Avena sativa L.)genotypes in Ethiopia using parametric and nonparametric stability statistics.Twenty-four oat genotypes were evaluated in nine environments using a randomized complete block design replicated three times.Results:The pooled analysis of the variance of grain yield showed significant variations among genotypes,environments,and their interaction effects.Significant GEI revealed the rank order change of genotypes across environments.The environment main effect captured 44.62%of the total grain yield variance,while genotype and GEI effects explained 28.84%and 26.54%of the total grain yield variance,respectively.The grain yield stability was assessed based on 12 parametric and two nonparametric stability statistics.The results indicated that genotypes with superior grain yield-showed stable performance on the basis of the stability parameters of the genotypic superiority index(P_(i)),the Perkins and Jinks adjusted linear regression coefficient(B_(i)),and the yield stability index(YSI),indicating that selection using these stability parameters would be efficient for grain yield enhancement in oat genotypes.Spearman's rank correlation coefficients also showed that the stability parameters of P_(i),B_(i),and YSI had a significant positive association with grain yield.However,grain yield had an inverse correlation with the stability parameters of standard deviation,deviation from regression (S_(di)^(2)),the Hernandez desirability index(D_(ji)),Wricke ecovalence(W_(i)),the Shukla stability variance(σ_(i)^(2)),the AMMI stability value(ASV),and environmental variance (S_(i)^((2))),indicating that oat genotype selection using these stability parameters would not be efficient for yield enhancement because these stability parameters favor low-yielding genotypes more,compared to high-yielding ones.Conclusions:Therefore,G5,G8,G11,G12,G14,G16,G17,G19,and G22 genotypes were adaptable in all nine environments based on stability parameters of Pi,Bi,and YSI,and selection of these superior genotypes would improve grain yield in oat genotypes.However,the validity of this result should be confirmed by repeating the experiment in the same environments over two or more years.

Soil organic carbon stock in Abune Yosef afroalpine and sub-afroalpine vegetation,northern Ethiopia

Introduction:Soil is the major reservoir of organic carbon.There is a paucity of soil organic carbon(SOC)stock data of afroalpine and sub-afroalpine vegetation in Ethiopia.Hence,this study was conducted to estimate the SOC stock and correlate it with soil physicochemical properties in Abune Yosef afroalpine and sub-afroalpine vegetation.Systematic sampling was employed to collect soil samples from upper 30 cm.Dry bulk density soil pH(1:2.5 water);organic carbon(Walkley and Black),and total nitrogen(Kjeldahl)were the methods used for soil analysis.Pearson correlation and linear regression analysis were performed in SPSS 24 statistical software.Results:The SOC stock of the study area was found to be 79.57 t C ha−1.Soil organic carbon stock showed statistically significant positive correlation with vegetation type(r=0.522,p<0.01),bulk density(r=0.62,p<0.01),total nitrogen(r=0.41,p<0.01),and altitude(r=0.468,p<0.01)and negative correlation with slope(r=−0.298,p<0.05).The present study revealed similar soil organic carbon stock(SOCS)with the Intergovernmental Panel on Climate Change(IPCC)default estimate for similar regions.Positive correlation of SOCS and altitude could be resulted from the variations in anthropogenic disturbances,temperature,and precipitation vegetation types.The negative correlation between SOCS and slope is the result from the predictably higher soil erosion at steeper slopes.Temporal livestock trampling increased the bulk density but never affected the SOCS to decline.Aspect did not show any significant relationship with SOCS due to either the under surveying of all aspects or similar solar radiation found in the study area.Moreover,gazing,aspect,and soil pH did not show statistically significant impact on SOCS.Conclusion:The SOCS of Abune Yosef afroalpine and sub-afroalpine vegetation is similar to the IPCC default estimate for similar regions.This is a great contribution both to the global and local terrestrial carbon sink.