JAAST Table of Content: August - 2015, 3(5)

Review Articles

Tesfaye Amene Dada..     pp. 48 - 56




Review work was done to assess the impact of climate change on the livestock production sector and the unique traits found in indigenous breeds to mitigate the climate changes. Currently the world is facing a number of challenges. Of which climate change is priority area. The effect of climate change on biodiversity in general and domestic animals in particular is articulated in different scale. Ethiopia as a poor country has little to do to curb the situation in terms of a variety of technologies. Climate change could be particularly damaging countries which are dependent on rain fed agriculture and under heavy pressure from food insecurity and often famine caused by natural disasters. Livestock production in Ethiopia is already under pressure from climate change due to change in water quality and quantity, animal feeds resources, heat Stress, and disease and vectors. However, as a country rich in biodiversity there are a number of options where the country could mitigate the problems faced in livestock production sector. To the truth of world dynamicity, livestock production and indigenous genetic resources utilization systems should have to be in line with this frequent and unpredictable changes. Indigenous cattle breeds are a valuable source of genetic material because of their adaptation to harsh climatic conditions, ability to better utilize the limited and poor quality feed resources and their tolerance to a range of disease found in different corner of the country. In economic terms, these indicative data suggests that such adapted breeds if managed properly, supported with appropriate research direction and comprehensive review of research done on indigenous cattle breeds, can provide insurance against possible change in production system. Therefore, in the context of climate change, strategies for livestock research and innovation, and indigenous cattle production in Ethiopia should be geared towards exploitation of cattle genetic resources and the utilization of such adapted indigenous breeds to cope up climate change.

Keywords:  Dynamics of the environment, Environmental changes, Indigenous cattle genetic resources.

Research Articles

Kassahun Sadessa2, Berhanu Bekele2, Arega Fedassa1 and T. Salveraj1.     pp. 57 - 65




The production of Garlic (Allium sativum L.) is threatened by white rot disease caused by Sclerotium cepivorum; which cause heavy yield losses. The development of biocontrol systems has provided an effective approach for reducing the losses and risk of environmental pollution associated with fungicides and fungicide resistance development. Therefore, the present study was carried out to evaluate the biocontrol potential of seven Trichoderma species viz., T. harzianum, T. hamatum, T. viride, T. oblongisporum, T. longibrachiatum, T. asperillum, and T. atroviride by both in-vitro and in-vivo work for their antagonistic and inhibition potential against garlic white rot pathogen. Dual culture technique was used for the radial growth of the pathogen and antagonists record. All but four isolates were highly antagonistic that they inhibited the growth and colonized the colony of the pathogen and there was statistically significant difference among those Trichoderma isolates. The overall inhibition effect of the antagonists on the pathogen‟s colony growth ranged from 43.9 to 59.3 %. Trichoderma hamatum had the highest inhibition effect (59.3%) followed by T. harzianum (53.3 %), T. oblongisporum (52.7 %), T.viride (51.8%), T. asperillum (50.2%), T. longibrachiatum (47.2%) and T. atroviride (43.9%) . Therefore, these isolates were further studied in the glasshouse condition by using single and in combination against garlic white rot. The incidence of S. cepivorum was significantly reduced in bulbs of garlic and also improved plant growth was observed in plants treated with single inoculation of T. hamatum alone followed by T. harzianum alone and in combined inoculation of T.hamatum and T. harzianum, T. oblongisporum and T. viride isolates. Plants inoculated with S. cepivorum alone showed pronounced disease symptoms with mean disease incidence of 90.5 %. Combined treatment of T.hamatum and T. harzianum isolates were significantly reduced (62.22%) the white rot disease of garlic followed by the combined inoculation of T. oblongisporum and T.harzianum and T. hamatum and T.viride. The over all reduction in the incidence of white rot was 62.22% in the treatment of T. hamatum and T. harzianum isolates followed by 53.72% for T. oblongisporum and T. harzianum. It is concluded that the tested Trichoderma isolates (T.hamatum, T.harzianum, T.oblongisporum and T.viride) have high potential to inhibit the colony growth of S. cepivorum and the results clearly pointed out that T.hamatum, T. harzianum, T .oblongisporum and T.viride isolates can reduce the severity of S. cepivorum disease in garlic. Use of these bio-control agents could be promoted as an active component of bio-intensive Integrated Disease Management Program (IDMP) under organic mode.

Keywords:  Garlic, Sclerotium cepivorum, Biological control, Trichoderma species..

Belay Zerga.     pp. 66 - 76




Origin and effect of ecosystem problems are often not easily definable. Ecosystem degradation has already resulted in noticeable and wide-ranging effects on the Ethiopian community-both rural and urban. Due to depletion of forests and the resultant increase in runoff, the storage of water has greatly diminished and a large number of water points for human and animal use have dried up. Ecosystem degradation leads to decrease in both the quality and number of livestock due to absence of fodder; any change in livestock sector has tremendous effects on the living standards of the rural people as a whole. Where agricultural land livestock production reach very low levels as a result of reduced cultivable land and yields, a situation will be created where there is insufficient land leading to shrinkage of average farm size which, in turn, creates a disguised unemployment. Ethiopia may stand number one in Africa (perhaps in the world) to witness the power of land degradation deriving people out of their homes. In 1984/85, more than half a million people were forced to leave their homes mainly in the highly eroded northern regions to the south and southwestern parts, which are less degraded so far. Plots have been abandoned and given up to grazing owing to the persistent erosion. The consequence is use of marginal lands on steep slopes or relatively unsuitable soils. New plots tend to be in remote areas, so more time has to be spent for travelling. Burning of dung as a result of depletion of forest resources reduces Ethiopia’s crop production while decline in the humus content of the soil causes a further fall in crop production of about one percent. The consequence is obvious: shortage of food and malnutrition. Where there is no forest resource at all, one cannot simply talk about the economic cost of getting fuel wood because there is no possibility to get it even if money is available. Over much of northern Ethiopia most of the land is absolutely treeless, so much so that in some rural areas only stones are used for building houses, and cow dung for fuel. Conflicts between different pastoralist communities have occurred frequently in history and continue up to date. They can have serious consequences too but are covered even less by the press.

Keywords:  Ecosystem degradation, drivers/causes of degradation, Ethiopia, Agricultural expansion, soil /land degradation, deforestation, population growth.