Genetic diversity of <Emphasis Type="Italic">Guizotia abyssinica</Emphasis> (L. f.) Cass. (Asteraceae) from Ethiopia as revealed by random amplified polymorphic DNA (RAPD)

Genetic diversity of 70 populations of niger (Guizotia abyssinica) representing all its growing regions in Ethiopia was investigated using random amplified polymorphic DNA (RAPD) to reveal the extent of its populations genetic diversity. Ninety-seven percent of the loci studied was revealed to be polymorphic for the whole data set. The within population diversity estimated by Shannon diversity index and Nei gene diversity estimates was revealed to be 0.395 and 0.158, respectively. The extent of genetic variation of populations from major niger producing regions was significantly lower than that of populations from other regions; however, it is distributed regardless of altitude of growth. Genetic differentiation between populations was estimated with Shannon index as G^′ _ST (0.432), Nei’s G _ST (0.242) and AMOVA based F _ST (0.350) and appears to be equivalent to the average values calculated from various RAPD based studies on outcrossing species. Higher proportion of the variation detected by AMOVA resided within populations (64.58%) relative to the amount of variation among populations (35.42%). UPGMA cluster analysis showed that most of the populations were clustered according to their region of origin. However, some populations were genetically distant from the majority and seem to have unique genetic properties. It is concluded that the crop has a wide genetic basis that may be used for the improvement of the species through conventional breeding and/or marker assisted selection. Collection of germplasm from areas not yet covered and/or underrepresented is the opportunity to broaden the genetic basis of genebank collection.     

Estimating the Effects of Tsetse Control on Livestock Productivity – A Case Study in Southwest Ethiopia

A tsetse control campaign was started in January 1991 using a synthetic pyrethroid cypermethrin 'pour-on' applied monthly to cattle exposed to high levels of drug-resistant trypanosomes in the Ghibe valley of southwest Ethiopia. In December 1992, a cost-recovery scheme was introduced, and thereafter farmers paid for treatment. An average of 100 village Ethiopian Highland Zebu cattle were monitored monthly from March 1986 to February 1997. Individual animals in this herd were treated with diminazene aceturate (Berenil, Hoechst, Germany) at 3.5 mg/kg when trypanosomes were detected and their packed cell volume was less than 26%. Superimposed on this systematic trypanocidal chemotherapy, control of tsetse resulted in average reductions from 1992 to 1996 of 95% and 75% in the mean relative densities of tsetse and biting flies, respectively, and of 63% in the prevalence of trypanosomal infections in cattle. Despite these reductions, there was no significant increase in the body weight of the cows, calving rate or the mean body weight of calves at 12 months of age. There was, however, an average decrease of 57% in calf mortality (including still births) by 12 months of age, an increase of 49% in the ratio of live calves under 12 months of age to cows over 36 months of age, and an increase of 8% in the body weight of adult males.     

Molecular phylogeny of genus <Emphasis Type="Italic">Guizotia</Emphasis> (Asteraceae) using DNA sequences derived from ITS

Complete sequences for the internal transcribed spacers of the 18s–26s nuclear ribosomal DNA were generated to establish phylogenetic relationships among five species of the genus Guizotia. Parsimony analysis and pairwise distance data produced a single tree with four clearly distinguished clades that accord with previously reported chromosomal data. The clades produced here have been discussed with reference to existing taxonomic treatments. It appears that Guizotia scabra ssp. scabra, G. scabra ssp. schimperi and Guizotia villosa have contributed to the origin of Guizotia abyssinica, the cultivated species of the genus. The present composition of the species of genus Guizotia and the subtribe the genus presently placed in are suggested to be redefined.     

Erratum to: Population genetics of self-incompatibility and developing self-compatible genotypes in niger (<Emphasis Type="Italic">Guizotia abyssinica</Emphasis>)

Niger (Guizotia abyssinica (L. f.) Cass. (Asteraceae) is a strictly self-incompatible crop species with a sporophytic self-incompatibility mechanism. This characteristic presents a number of difficulties in plant improvement programs. The objective of this study was to determine the number and distribution of S-alleles in Ethiopian niger populations and to identify and develop self-compatible genotypes with various associated advantages. Several aspects of self-incompatibility in niger were compared in self- and cross-pollination experiments in which seed-set was considered to be a measure of compatibility. Our results indicate the presence of a minimum of ten self-incompatibility alleles and one self-compatibility allele at the S-locus in niger. Most of these alleles behave differently in the pollen and pistil. About two-thirds of the allelic interactions in both the pollen and pistil were dominant/recessive, and one-third were codominant. The reciprocal cross-pollinations (RCPs) resulted in progeny with similar levels of compatibility within and among populations because of a wide distribution of S-alleles in the populations and, consequently, low population differentiation at the S-locus. An analysis of molecular variance (AMOVA) revealed that only 2% of the total genetic variation at the S-locus differentiates the populations. In conclusion, self-compatible genotypes from the Ethiopian niger gene pool have been identified and developed for the first time.     

Assessment of the nutritional status of indigenous scavenging chickens in Ada’a district,Ethiopia

The nutritive values of scavenging feed resource bases and effects of season and chickens age on the latter were studied in smallholder farms in Aad’a, Ethiopia. The study included 210 households and 208 chickens. The mean weight of crop contents in all age groups ranged from 26.2 to 28.2 g, while it was 29.8 g and 24.7 g in the harvesting and non-harvesting seasons, respectively. Grains represented 48–49% of the mean weight of crop contents in all age groups and it was significantly higher (P < 0.05) during the harvesting season than the non-harvesting period in both age groups. Kitchen wastes were next in abundance (26–29%) and were significantly more abundant in non-harvesting season in growers only and in hens than in growers (P < 0.001). The dry matter, crude protein, crude fiber, calcium, phosphorous and metabolizable energy levels of crop contents were 91.1–92.5%, 12.9–15.5%, 4.17–7.07%, 0.43–0.90%, 0.28–0.38% and 3404.3–3636.2 Kcal, respectively. Crude protein, calcium and phosphorus levels were below the requirements for egg production and growth. The scavenging feed resource base was critically deficient in these nutrients during the harvesting season. As these nutrients are vital for production, supplementary feeds rich in these nutrients would probably result in increased egg production and optimum growth.     

Genetic diversity analysis in Phaseolus vulgaris L. using morphological traits

Common bean (Phaseolus vulgaris) is an important export crop in Kyrgyzstan since the end of the twentieth century. Genetic diversity analysis of common bean populations is useful for breeding programs, as it helps to select genetic material to be used for further crossing. Twenty-seven common bean accessions were analyzed using 13 qualitative morphological traits. In some cases, obtained morphological data were combined with previously published results based on microsatellite markers. The similarity matrices generated from the molecular and morphological data were significantly correlated (r = 0.49, P < 0.01). Cluster analyses based on Dice’s similarity coefficient were constructed based on morphological data and the combined data set of morphology and microsatellite, and both grouped the 27 accessions according to their origin: 15 belonged to the Andean and 12 to the Mesoamerican gene pool. On average, the Andean accessions were less diverse than the Mesoamerican accessions. The average diversity based on the Shannon diversity index for the 13 qualitative morphological traits was 0.05. Overall, this study revealed that qualitative morphological markers are efficient in assigning modern cultivars to their gene pools of origin.     

Livestock keeper perceptions of four indigenous cattle breeds in tsetse infested areas of Ethiopia

Four cattle breeds indigenous to western and south-western Ethiopia - Abigar, Gurage, Horro and Sheko - were included in a study of the perceptions of smallholder cattle keepers regarding cattle management, production levels and constraints for production. A semi-structured questionnaire was used and 60 cattle keepers from each of the four areas were interviewed. Diseases were reported as the main constraint to cattle production by a majority of livestock keepers in all areas except in the Sheko area, where over-stocking was the main constraint. Among diseases, trypanosomosis was the main livestock disease according to more than half of Gurage, Horro and Sheko keepers, whereas anthrax was most important in the Abigar area. Gurage had highest age at first calving, longest calving interval and also the lowest milk production, whereas Sheko and Abigar had the most favorable characteristics both for milk production (600–700 kg) and fertility (age at first mating 3–3.5 years and above 8 calves/cow). Cattle keepers in the Sheko area reported relatively less problems with cattle diseases compared to the other areas, especially regarding trypanosomosis. Abigar showed a different disease pattern than the other breeds and may also have advantages as regards trypanotolerance.     

Land-use and land-cover dynamics in response to changes in climatic,biological and socio-political forces: the case of southwestern Ethiopia

Few studies of land-use/land-cover change provide an integrated assessment of the driving forces and consequences of that change, particularly in Africa. Our objectives were to determine how driving forces at different scales change over time, how these forces affect the dynamics and patterns of land use/land cover, and how land-use/land-cover change affects ecological properties at the landscape scale. To accomplish these objectives, we first developed a way to identify the causes and consequences of change at a landscape scale by integrating tools from ecology and the social sciences and then applied these methods to a case study in Ghibe Valley, southwestern Ethiopia. Maps of land-use/land-cover change were created from aerial photography and Landsat TM imagery for the period, 1957–1993. A method called `ecological time lines' was developed to elicit landscape-scale explanations for changes from long-term residents. Cropland expanded at twice the speed recently (1987–1993) than two decades ago (1957–1973), but also contracted rapidly between 1973–1987. Rapid land-use/land cover change was caused by the combined effects of drought and migration, changes in settlement and land tenure policy, and changes in the severity of the livestock disease, trypanosomosis, which is transmitted by the tsetse fly. The scale of the causes and consequences of land-use/land-cover change varied from local to sub-national (regional) to international and the links between causes and consequences crossed scales. At the landscape scale, each cause affected the location and pattern of land use/land cover differently. The contraction of cropland increased grass biomass and cover, woody plant cover, the frequency and extent of savanna burning, and the abundance of wildlife. With recent control of the tsetse fly, these ecological changes are being reversed. These complex patterns are discussed in the context of scaling issues and current conceptual models of land-use/land-cover change.