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Yam plant has a major role in Ethiopia particularly in densely populated areas of south, southwestern, and western parts of the country. It grows in a wide range of soils with an altitude range of 1140 to 2200 masl. This study was done to identify yam species collected from major producing areas of the country. The total of sixty yam accessions from ten different geographic origins of South and Oromiya region of Ethiopia were used. The collected samples were planted in complete randomized block design at two research sites of South Agricultural Research Institute. Forty-five qualitative morphological characterizations were used to characterize and identify Dioscorea species. Among these qualitative characters observed in the study presence and absence of spines on stems and roots, number of male and female inflorescence, stem length, twining direction, and flesh color were the major traits considered for species identification. The organoleptic properties evaluation was carried out using fifteen selected local farmers. Statistical analysis was done using Numerical Taxonomy and Multivariate Analysis System Version 2.02 NTSYpc software program and the data reduction function of SPSS for windows. Based on this study, sixty yam germplams of ten major growing areas of the country were identified into six Dioscorea species. These identified Dioscorea species were again subjected to qualitative morphological characterization and 33 morphological traits revealed variability. This implies presence of high diversity in yam (Dioscorea species) of Ethiopia. Most of the morphological variations among the yam genotypes were contributed by young petiole color, tendency of tuber to branch, and tuber flesh color. Hence, these morphological traits could be taken as useful traits for identification of yam cultivars.

Background Korarima (Aframomum corrorima) is a perennial and aromatic herb native and widely distributed in southwestern Ethiopia. It is known for its fine flavor as a spice in various Ethiopian traditional dishes. Few molecular studies have been performed on this species so far. In the present paper, the ISSR technique was employed to study the genetic diversity in populations of cultivated A. corrorima. Results Seven ISSR primers produced a total of 86 clearly scorable DNA bands. High levels of genetic diversity were detected in cultivated A. corrorima (percentage of polymorphic bands = 97.67%, gene diversity = 0.35, Shannon’s information index = 0.52). Analysis of molecular variance (AMOVA) showed that 27.47% of the variation is attributed to the variation among populations and 72.53% to the variation within populations. The Fst (0.28) value showed a significant (p

Background Korarima [Aframomum corrorima (Braun) P.C.M. Jansen] is a spice crop native to Ethiopia. Understanding the extent and partitioning of diversity within and among crop landraces and their wild relatives is among the first steps in conserving and measuring their genetic potential. The present study is aimed at characterizing the population genetic structure and relationships between cultivated and wild korarima in the southwestern part of Ethiopia. Results We analyzed a total of 195 individuals representing seven wild and fourteen cultivated populations. Eleven polymorphic simple sequence repeat (SSR) markers were used. We observed a total of 53 alleles across the eleven loci and individuals. In total, 32 alleles were detected in the cultivated populations, whereas 49 alleles were detected in the wild populations. We found higher genetic diversity in wild populations than in the cultivated counterpart. This result implies the potential of wild korarima as a possible source for novel alleles contributing to the improvement of cultivated korarima. Analysis of molecular variance (AMOVA) showed significant but low differentiation between cultivated and wild korarima populations. Similarly, neighbour-joining and STRUCTURE analyses did not group cultivated and wild populations into two distinct clusters. The lack of clear differentiation between cultivated and wild populations could be explained by historical and contemporary gene flow between the two gene pools. Conclusion The 11 SSR loci developed in this study could be employed to examine genetic diversity and population structure of korarima in other countries as well as other Aframomum species. From the five administrative zones considered in this study, the Bench-Magi and Sheka zone showed populations with high genetic diversity, and these populations could be used as a potential starting point for in-situ and ex-situ germplasm conservation and korarima improvement through breeding programs after proper agronomic evaluation. Electronic supplementary material The online version of this article (doi:10.1186/s12863-017-0540-4) contains supplementary material, which is available to authorized users.

A study was carried out between 2008 and 2011 to investigate the potential risks of gene flow and its consequences in the crop–wild–weedS. bicolorcomplex in Ethiopia to aid efforts to conserve genetic diversity. Morphological measurements and genomic DNA samples were takenin situfrom 30 wild and eight cultivated populations representing a total of 760 samples from five regions. Genetic diversity, gene flow, population structure and outcrossing rates of wild populations were computed using phenotypic measurements and/or polymorphic simple sequence repeat (SSR) markers. Moreover, morphological analyses of fitness of crop–wild hybrids were studied. High diversity was observed among the wild/weedy sorghum populations for phenotypic traits and SSRs. SSR diversity was high in both wild and cultivated populations, but the magnitude was greater in the former. Gene flow between the wild and the cultivated sorghum was observed to be higher than that within either pool. Wild sorghums exhibited variation in the multilocus outcrossing rate (range = 0.31–0.65) and fitness was not compromised in most wild × crop hybrids. The study indicated that crop-to-wild gene flow is possible in Ethiopia. Thus, genes from transgenic sorghum are expected to enter into the wild and non-transgenic cultivated populations and may spread and persist, if transgenic sorghum is deployed in Ethiopia and in other countries of Africa, which may pose risk of introduction of unwanted effects, which in turn may lead to loss of genetic diversity.

Yam (Dioscorea spp L.) is one of root and tuber crops grown in Ethiopia as source of food and income. It is cultivated mainly in south, southwest, and western part of the country. Two hundred ten yam accessions from ten different geographic origins of major growing areas of the country were used in this study. The sprouted tubers of some accessions were received from research centers where others were directly collected from farmers’ fields during early March, 2010. The collected yam genotypes were planted in complete randomized block design at two research sites (namely at Hawasa and Wonago) which are found under South Agricultural Research Institute in the end of April 2010. All important cultural practices such as staking, weeding and irrigation were done starting from planting till harvesting. Yam leaf samples with of different origin were observed separately using twenty SSR markers. A similarity matrix derived UPGMA cluster analysis based on geographical sites showed nine distinct clustering groups which indicated presence of relationship between genetic distances to that of geographical distance in most of clustering groups. These cluster grouping is supported by Analysis of Molecular Variance (AMOVA) that indicated presence of significance genetic variation of 210 yam accessions within and among ten collection sites.

Noug (Guizotia abyssinica) is a semidomesticated oil-seed crop, which is primarily cultivated in Ethiopia. Unlike its closest crop relative, sunflower, noug has small seeds, small flowering heads, many branches, many flowering heads, and indeterminate flowering, and it shatters in the field. Here, we conducted common garden studies and microsatellite analyses of genetic variation to test whether high levels of crop–wild gene flow and/or unfavorable phenotypic correlations have hindered noug domestication. With the exception of one population, analyses of microsatellite variation failed to detect substantial recent admixture between noug and its wild progenitor. Likewise, only very weak correlations were found between seed mass and the number or size of flowering heads. Thus, noug's ‘atypical’ domestication syndrome does not seem to be a consequence of recent introgression or unfavorable phenotypic correlations. Nonetheless, our data do reveal evidence of local adaptation of noug cultivars to different precipitation regimes, as well as high levels of phenotypic plasticity, which may permit reasonable yields under diverse environmental conditions. Why noug has not been fully domesticated remains a mystery, but perhaps early farmers selected for resilience to episodic drought or untended environments rather than larger seeds. Domestication may also have been slowed by noug's outcrossing mating system.

Genetic diversity assessment of genetic resources maintained at Gene-Banks has important implication for future improvement, conservation and collection activities. However, such information is not available for sesame collected by IBC, Ethiopia. Inter simple sequence repeat (ISSR) marker was used to assess the level of genetic diversity, genetic structure and genetic distance, and to indirectly estimate the level of gene flow among populations of sesame in Ethiopia. A total of 120 (82 Ethiopian and 38 exotic) sesame accessions and six ISSR primers were used. DNA was extracted using a triple CTAB extraction method from silica gel dried bulked sample of five randomly selected individual plants per accession at the stage of three to four weeks after planting. The presence of higher polymorphism was revealed among accessions collected from Ethiopia (75.85) than the exotic accessions (65.52). The average gene diversity relative to the overall population was 0.24. Samples from Welega was the most diverse, with gene diversity value of 0.26 followed by samples from Tigray (0.20) and Shewa (0.20). Samples from Gojam (0.10) and Sudan (0.12) were the least diverse. Inter-population genetic distance (D) ranged from 0.031 to 0.165 for the overall population. From the exotic accession, samples of South East Asia are distantly related to most of the Ethiopian accessions. Unweighted pair group method with arithmetic mean analysis (UPGMA) of Ethiopian sesame populations revealed two major groups and three outliers (Cultivated, Welega and Illubabore). Key words: Bulk sampling, gene flow, genetic differentiation, genetic distance, inter simple sequence repeat (ISSR), genetic diversity and sesame landrace accessions.

Since the immediate wild relatives ofSorghum bicolor(L.) Moench are indigenous to Ethiopia, studying their population biology is timely for undertaking conservation measures. A study was conducted to investigate the occurrence of population bottlenecks and to estimate the long-term effective population size (Ne) in wild relatives of sorghum. For this, 40 samples of wild sorghum were collected from two remotely located populations that were allopatric to the cultivated sorghum. The presence of bottlenecks was investigated using heterozygosity excess/deficiency, mode shift and allelic diversity based on nine polymorphic simple sequence repeat (SSR) loci. We also estimated theNeof the studied populations using two different methods employing SSR mutation models. The expected heterozygosity was found to be 0.41 and 0.71 and allelic richness was 3.0 and 4.9, in Awash and Gibe populations, respectively. Neither the heterozygosity excess nor the mode-shift methods detected signatures of bottlenecks in the studied populations. The effective size of the two wild sorghum populations studied also showed no risk of population reduction in these regions of Ethiopia. Therefore, these allopatric wild sorghum populations can survive by occupying patches by the roadsides and fences, areas within abandoned farm lands, forests, etc., which shows that their wild characteristics of adaptation have been adequate for them to survive from extinction despite extensive deforestation of their habitat for modern agriculture and frequent grazing by livestock. However, this does not guarantee the survival of these species for the future andex situconservation measures or policies could help maintain their diversity.

Forests of SW Ethiopia constitute the native habitat of Coffea arabica and also the place where domestication of Arabica coffee started. Selection from wild populations has led to numerous landraces (farmer’s varieties) and cultivars. Inter-simple sequence repeats (ISSRs) were generated from a representative set of forest coffee populations and landraces across Ethiopia. For the broad diversity assessment, nine di- and tri-nucleotide ISSR primers were applied, as chosen from a total of 102 primers tested initially. Tetranucleotide ISSR primers differed in amplifying fingerprints that could hardly be analysed due to excessive variation. Tree building analysis (NJ, UPGMA) of 84 polymorphic loci amplified for 125 C. arabica individuals provided evidence for several groups of related genotypes occurring in certain geographical areas of Ethiopia and underscored the existence of wild coffee distinct from landraces. Landraces seem to have originated in different geographical areas of Ethiopia in a stepwise domestication process. While the overall geographical signal in the dataset was weak, analysis in a Bayesian framework using the admixture model with geographical priors in STRUCTURE recovered some genetic clustering. Based on Shannon’s diversity index, populations from Yayu (0.47) and Bonga (0.46) showed highest diversity, followed by individuals from Berhane Kontir (0.41). A likely scenario for the differentiation of C. arabica after an allopolyploidization event is that the hierarchical-geographical patterning of wild Coffea genotypes expected from stepwise range extension was obscured by recent or ancient gene flow. The diversity and geographical distribution of autochthonous C. arabica genotypes indicates the need for a multi-site in situ conservation approach.

Natural hybridization between wild/weedy and crop species often results in rare hybrids, which can be more weedy and difficult to control. Moreover, the advent of transgenic crop plants raises questions of biosafety risk assessment on the consequences of rare hybrids with possible fitness enhancing genes on the environment. This study aimed at measuring the fitness components of wild–crop sorghum hybrids for various juvenile survival and adult morphological and fertility characters as part of the risk assessment of transgenic sorghum in Africa where the crop was believed to have first domesticated and serves as the major staple. Out of a pool of hybrids made in 2010 from 23 wild sorghum accessions and two released cultivated sorghum varieties using hand emasculation techniques, seven were selected for the field study of their fitness components in 2011. The study confirmed that crop–wild hybrids of sorghum are fertile. Two approaches were followed (relative fitness and mid-parent heterosis) which showed that most of the hybrids were as fit as their wild parents, and in some cases they showed mid-parent heterosis for the measured traits. The results of this study highlighted a potential risk that hybrids carrying crop genes (including herbicide resistance transgenes) could pose because they could be more weedy than their wild/weedy parents if transgenic sorghum is deployed in regions where the wild and cultivated sorghum populations coexist, such as in Ethiopia and in other parts of Africa.

Because transgenic sorghum (Sorghum bicolor L.) is being developed for Africa, we investigated the potential for transgenes to spread to conspecific wild/weedy sorghum populations in Ethiopia, which is considered the centre of origin of cultivated sorghum. In the current study, the extent of outcrossing, and uniparental and biparental inbreeding were investigated in seven wild/weedy sorghum populations collected at elevations ranging from 631 to 1709 m. Based on allele frequency data of 1120 progenies and 140 maternal plants from five polymorphic microsatellite markers, outcrossing rates were estimated using standard procedures. The average multilocus outcrossing rate was 0.51, with a range of 0.31-0.65 among populations, and the family outcrossing rate was in the extreme range of 0 to 100%. The highest outcrossing (t(m) = 0.65) was recorded in a weedy population that was intermixed with an improved crop variety in Abuare (Wello region). It was also observed that the inbreeding coefficient of the progenies (F(p)) tend to be more than the inbreeding coefficient of both their maternal parents (F(m)) and the level of inbreeding expected at equilibrium (F(eq)), which is a characteristic of predominantly outbreeding species. Biparental inbreeding was evident in all populations and averaged 0.24 (range = 0.10-0.33). The high outcrossing rates of wild/weedy sorghum populations in Ethiopia indicate a high potential for crop genes (including transgenes) to spread within the wild pool. Therefore, effective risk management strategies may be needed if the introgression of transgenes or other crop genes from improved cultivars into wild or weedy populations is deemed to be undesirable.

Extensive studies of genetic diversity and population structure important for conservation of wild sorghum are yet lacking in Ethiopia, the centre of origin for cultivated sorghum. To assess both genetic diversity and the probability of gene flow between wild and cultivated types, collections of wildSorghum bicolorwere made from regions in Ethiopia where wild and cultivated sorghum coexist. Morphological data were recordedin situfor both quantitative and qualitative characters from 30 populations in five diverse geographical regions and eight agroecologies. High phenotypic diversity was observed among the wild and weedy sorghum populations. The overall standardized Shannon–Weaver diversity index (H′), computed from the frequencies of all qualitative traits, ranged from 0.47 to 0.98 with an average value of 0.76. Moreover, warm semi-arid lowland (SA2) agroecologies, which contain Tigray populations, supported the highest diversity for these traits. Subspeciesverticilliflorumanddrummondii(the two major subspecies of wildS. bicolor) were observed in diverse habitats throughout northern and central Ethiopia. In some areas, weedy types showed domestication traits including the absence of awns and reduced seed shattering. The existence of morphologically intermediate forms indicates that gene flow between cultivated and wild forms has likely occurred. Deployment of transgenic crop sorghum, therefore, would pose a distinct risk for transgene movement into wild Ethiopian populations.

Parsimony-based phylogenetic analyses of the genus Guizotia were undertaken based on DNA sequence data from the following chloroplast DNA (cpDNA) regions: trnT-trnL, trnL-trnF, trnY-rpoB, trnC-petN, psbM-trnD and rps16-trnQ intergenic spacers, trnL, rps16 and matK-5′trnK introns and matK gene. Out of the 26 primers used in this study, 14 were newly designed. The study was conducted to determine (1) the closest relative of Guizotia abyssinica, (2) the taxonomic status of some Guizotia taxa and (3) the subtribal placement of Guizotia in the tribe Heliantheae. The analyses of the sequence data showed that G. abyssinica, G. scabra ssp. scabra, G. scabra ssp. schimperi and G. villosa are phylogenetically closely related. However, G. scabra ssp. schimperi appeared as the most closely related taxon to G. abyssinica. Based on this phylogenetic analysis, we suggest that the two subspecies of G. scabra are better treated as separate species. The analysis also clearly demonstrated that “Chelelu” and “Ketcha” are distinct Guizotia species. The trnT-trnL and trnL-trnF intergenic spacer-based phylogenetic analysis of various subtribes of the tribe Heliantheae strongly supports the placement of the genus Guizotia within the subtribe Milleriinae.

MYH9 has been proposed as a major genetic risk locus for a spectrum of nondiabetic end stage kidney disease (ESKD). We use recently released sequences from the 1000 Genomes Project to identify two western African-specific missense mutations (S342G and I384M) in the neighboring APOL1 gene, and demonstrate that these are more strongly associated with ESKD than previously reported MYH9 variants. The APOL1 gene product, apolipoprotein L-1, has been studied for its roles in trypanosomal lysis, autophagic cell death, lipid metabolism, as well as vascular and other biological activities. We also show that the distribution of these newly identified APOL1 risk variants in African populations is consistent with the pattern of African ancestry ESKD risk previously attributed to MYH9. Mapping by admixture linkage disequilibrium (MALD) localized an interval on chromosome 22, in a region that includes the MYH9 gene, which was shown to contain African ancestry risk variants associated with certain forms of ESKD (Kao et al. 2008; Kopp et al. 2008). MYH9 encodes nonmuscle myosin heavy chain IIa, a major cytoskeletal nanomotor protein expressed in many cell types, including podocyte cells of the renal glomerulus. Moreover, 39 different coding region mutations in MYH9 have been identified in patients with a group of rare syndromes, collectively termed the Giant Platelet Syndromes, with clear autosomal dominant inheritance, and various clinical manifestations, sometimes also including glomerular pathology and chronic kidney disease (Kopp 2010; Sekine et al. 2010). Accordingly, MYH9 was further explored in these studies as the leading candidate gene responsible for the MALD signal. Dense mapping of MYH9 identified individual single nucleotide polymorphisms (SNPs) and sets of such SNPs grouped as haplotypes that were found to be highly associated with a large and important group of ESKD risk phenotypes, which as a consequence were designated as MYH9-associated nephropathies (Bostrom and Freedman 2010). These included HIV-associated nephropathy (HIVAN), primary nonmonogenic forms of focal segmental glomerulosclerosis, and hypertension affiliated chronic kidney disease not attributed to other etiologies (Bostrom and Freedman 2010). The MYH9 SNP and haplotype associations observed with these forms of ESKD yielded the largest odds ratios (OR) reported to date for the association of common variants with common disease risk (Winkler et al. 2010). Two specific MYH9 variants (rs5750250 of S-haplotype and rs11912763 of F-haplotype) were designated as most strongly predictive on the basis of Receiver Operating Characteristic analysis (Nelson et al. 2010). These MYH9 association studies were then also extended to earlier stage and related kidney disease phenotypes and to population groups with varying degrees of recent African ancestry admixture (Behar et al. 2010; Freedman et al. 2009a, b; Nelson et al. 2010), and led to the expectation of finding a functional African ancestry causative variant within MYH9. However, despite intensive efforts including re-sequencing of the MYH9 gene no suggested functional mutation has been identified (Nelson et al. 2010; Winkler et al. 2010). This led us to re-examine the interval surrounding MYH9 and to the detection of novel missense mutations with predicted functional effects in the neighboring APOL1 gene, which are significantly more associated with ESKD than all previously reported SNPs in MYH9. Electronic supplementary material The online version of this article (doi:10.1007/s00439-010-0861-0) contains supplementary material, which is available to authorized users.

Complete sequences of transcribed spacers and introns from the trnT trnF region of chloroplast DNA (cp DNA) were generated from Musaceae species to establish the phylogenetic relationships among 3 species of Ensete including the economically important Ensete ventricosum (Welw.) Cheesman and 13 species of Musa. Parsimony analysis and pair wise distance data produced a single tree, with Ensete and Musa as clearly distinguished clades. Six Musa and three Ensete clades were generated. The topology of these clades did not change when the data were split into spacers and introns, although the split resulted in poor bootstrap support. Removing a hotspot from the entire data set improved clade support. The clades produced are discussed with reference to existing taxonomic and phylogenetic treatments. In contrast to previous suggestions, most of the Rhodochlamys species that we investigated clustered together with strong support establishing their distinctiveness from the Musa species studied. Ensete glaucum (Roxb.) Cheesman and Musa beccartii Simmonds appear to represent ancestral forms of Ensete and Musa, respectively for the presently studied species, and both genera have a common ancestor that is yet to be established. Our data also show that E. ventricosum cannot be reduced to E. glaucum, nor can E. gilleti (De Wild.) Cheesman be reduced to E. ventricosum, as some authorities have suggested. Ensete gilleti or a species very close to it appears to be the ancestral species of E. ventricosum.

Seventeen populations of niger (Guizotia abyssinica), representing all regions in Ethiopia where this crop is grown, were investigated using the amplified fragment length polymorphism (AFLP) technique, in order to determine the extent and distribution of its genetic diversity. A total of 539 AFLP loci were scored using seven primer combinations applied to 170 individual plants. Of these, 90% were polymorphic and all the individuals investigated were genetically unique. Despite the fact that most of the variation was within populations, populations were differentiated at a significant level (analysis of molecular variance;P

Amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) were employed to examine the genetic relationship between Guizotia taxa, to suggest the taxonomic status of some of these taxa, and to identify their diagnostic markers. Results from AFLPs and RAPDs share some features in common, both revealing G. scabra ssp. schimperi as the most closely related taxon to G. abyssinica, and indicating that G. arborescens and G. zavattarii are the most divergent taxa. Most of the diagnostic markers revealed in this study were specific to G. arborescens and G. zavattarii. Our analysis suggests that G. scabra ssp. scabra, G. scabra ssp. schimperi, Chelelu and Ketcha are separate species. In this study, AFLP was found to be superior to RAPD in detecting genetic variation, in internal consistency of the data and in the fitness of its clusters to genetic similarity data. AFLPs revealed genetic relationship between Guizotia taxa that is more inline with the cytogenetic and hybridization studies than that revealed by RAPDs.

Amplified fragment length polymorphism (AFLP) and random amplified polymorphic DNA (RAPD) markers were used to provide estimates of the comparative genetic variation within and among populations of various Guizotia taxa with the goal of conserving and utilizing their genetic diversity. The percentage of polymorphic loci (PS) ranged from 28.5% � 90% (AFLP) and 85.6% � 99.6% (RAPD). The overall gene diversity estimate ( /H T ) has shown slight variation among taxa ranging from 0.32 � 0.37 (AFLP) and from 0.22 to 0.28 (RAPD). The within population diversity of ‘‘Chelelu’’ and ‘‘Ketcha’’ was found to be unexpectedly high. Both parameters used to estimate population differentiation (GST and FST ) revealed the highest population differentiation in G. zavattarii followed by G. arborescens. Genetic variation among populations within a taxon was highly significant for all the five taxa as revealed by AMOVA (PB0.0001). The need for immediate conservation activities for G. arborescens and G. zavattarii, and factors that contribute to the existing genetic variability and population genetic structures are discussed.

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.

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.

An extraction solution that is optimal for protoplast release in Eragrostis tef (Zucc.) Trotter and Sorghum bicolor (L.) Moench consists of 1% Cellulysin, 0.5 % Macerozyme and 2 % Cellulase Onozuka, 1 mM CaCl2, 5 mM 2, (n-morpholino) ethane sulfonic acid, and 0.4 M mannitol. A culture medium consisting of two parts of Gamborg et al. medium, three parts of Murashige and Skoog medium, 1 % Schenk and Hildebrandt powder vitamin, 1 mg/l matin, 10 mM glutamine, 10 mg/l of 2,4-dichlorophenoxyacetic acid, and 10 mg/l naphthaleneacetic acid, was optimal for the survival and division of a small fraction of cultured protoplasts and protoplast fusion products. Electroporation and heat shock treatments stimulated cell wall formation and cell division in both sorghum and tef. Electrical parameters and conditions for fusing tef and sorgum were determined. Field pulse conditions for eventual electrogene transfer in tef and sorghum consisted of 700 and 400 V/cm, respectively, at 20°C and 40μs field pulse duration.

In vitro somatic embryogenesis and plant regeneration from root and leaf explants and from seeds were studied using eight genotypes of Eragrostis tef at various concentrations (1–10 mg/l) of 3,6-dichloromethoxybenzoic acid (3,6-D) and 2,4-dichloromethoxybenzoicacid (2,4-D). Optimal conditions for callus growth, embryogenesis and plant regeneration were evaluated. The callus biomass and the ability to regenerate plants were found to be functions of type of explant and hormone concentration. The callus fresh weight from leaf was higher than that from root, and different genotypes differed in their callus fresh weight. Unlike leaf induced callus, the root induced callus showed no significant differences between genotypes and treatments. The fresh weight of callus from seeds of most genotypes studied was similar. The number of direct regenerants from callus maintained on callus induction medium varied among the genotypes studied. On the whole, the number of regenerants from leaf callus was higher than that from root callus at all tested hormone concentrations. 1 and 2.5 mg/l of 3, 6-D gave the highest numbers of regenerants from calli transferred to embryogenesis medium. The various tef genotypes differed in their capacity to regenerate plants. Establishment of cell suspension cultures from root and leaf explants was also accomplished.

Albumin, globulin, and prolamin fractions were extracted from seeds of tef (Eragrostis tef (Zucc.) Trotter) and separated using several SDS-PAGE procedures and 1-D isoelectric focusing. This showed that all fractions were highly polymorphic, with differences in the prolarnin fractions allowing the 37 cultivars and lines to be classified into seven groups, each containing between one and fourteen lines. The results also indicate that there is potential to exploit the polymorphism in albumins and globulins in order to identify genotypes with enhanced nutritional quality.

Summary A total of 415 sorghum (Sorghum bicolor (L.) Moench) accessions representing different regions of Ethiopia, Eritrea and a group of introduced lines were evaluated for 15 quantitative characters to determine the extent and geographical pattern of morphological variation. The extent of variation was highly pronounced for agronomically important characters for sorghum. These characters included plant height, days for 50% flowering, peduncle exsertion, panicle length and width, number and length of primary branches per panicle and thousand seed weight. Significant regional variation was also observed for most of the characters. The results implied that environmental factors such as altitude, rainfall, temperature and growing period are important in regional variation. Mean for plant height and for days for 50% flowering showed clinal variation along the gradients of rainfall pattern and growing period in Ethiopia. Moreover, there were significant positive correlation coefficients between most of the characters. This included the correlation between agronomic characters of primary interest in sorghum breeding such as plant height and days for 50% flowering and also between various characters and the altitude of the collection sites. The implications of the results in plant breeding, germplasm collection and conservation as well as the probable sources of the wide range of variation are discussed.

The non-coding chloroplast DNA sequences of the trnL (UAA) intron and the trnL-trnF (GAA) intergeneric spacer (IGS), the coding sequences of nuclear 18S rDNA, and the transcription factor Vp1 of the cereal tef (Eragrostis tef (Zucc.) Trotter) were studied. No intraspecific variation was found among the 6 studied tef varieties. However, the study displayed that Eragrostis tef has a number of unique traits compared to other grasses. Phylogenetic analysis of the chloroplast DNA gave three grass clades, joining Eragrostis with sorghum and maize in one. In the analysis of the 18S rDNA sequences, the three grass species were joined in a monophyletic trichotomy in the cladogram, in which maize is the most divergent, rice the least and tef intermediate. The Vp1 is highly conserved. The Vp1 phylogeny showed that the tef Vp1-sequence is the hitherto most divergent Vp1-sequence reported from a grass.

Fifty grass pea land race populations of Ethiopia that were selected based on administrative regions and different altitude classes were used in this study to determine variability in morphological characters, Oxalyl Diamino Propanoic acid(ODAP) – a causative agent of lathyrism, and protein contents and their associations. Highly significant differences were observed among the populations for most of the morphological characters. Populations collected from Gondar region and the higher altitude group (>2550 m) showed the highest mean and coefficient of variation indicating the presence of high genetic diversity in this region and altitude group. ODAP analysis from single plants showed significant variation both within a population and between populations. Four individual plants with low ODAP contents ranging from 0.149% to 0.182% (range within safe level) were identified in populations collected from different regions, indicating the diversity and variation of this trait with in one population and between regions. These low ODAP lines are considered important for further breeding. The association of ODAP with grain yield, biomass, plant height and seed size was negative, suggesting that the selection of tall and late maturing varieties with large seed size and high grain yield potential will enable the development of varieties with low ODAP content.

Fifty grass pea (Lathyrus sativus L.) populations collected from different administrative regions and altitude classes in Ethiopia, were evaluated for variations of five morphological traits. Shannon-Weaver diversity index was calculated for traits, populations and altitude classes. Monomorphism was recorded in flower color (blue) for most of the populations. Olive seed colour was dominantly distributed in all regions with mean frequency of 50% while black seed colour is rare with mean frequency of 4% in Ethiopia. Much variability was observed within populations. High diversity values for pattern of testa colour and leaflet size were recorded in populations of highland origin (>2550 m.a.s.l.). Shannon's diversity index is highest in Gondar (H′ = 0.65) followed by Tigray region (H′ = 0.64) even though there was no significant variation in H′ values between regions. These regions with high diversity are recommended for immediate in situ and ex situ conservation.

Fourty two yam (Dioscorea species) sprouted tubers were collected from six different major growing regions of Ethiopia and planted at Hawasa Agricultural Research Center. The Dioscorea species considered in this study were D. bulbifera, D. abyssinica, D. cayenensis, D. rotundata, D. praehensilis, and D. alata. Five Proximate compositions (moisture, ash, crude fat, crude protein and crude fibre) and four minerals content (calcium, phosphorous, zinc and iron) were determined from 100g yam tubers at Ethiopian Health and Nutrition Research Insititute (EHNRI). High variability was observed among and within yam species due to their proximate composition and mineral content. The range of protein, moisture, iron, fat, fibre, ash, zinc, calcium and phosphorous content for all the fresh yam tubers observed in the study were between (3.13% - 6.29%),(4.67% -13.57%), (17.21mg/100g. - 90.85mg/100g), (0.26% - 7.86%), (1.82% - 6.36%), (1.68% - 4.41%), (0.38 mg/100g - 8.33 mg/100g), (6.3 mg/100g - 121.26 mg/100g) and (8.72 mg/100g. - 56.12 mg/100g) respectively. The correlation study indicated that presence of significance association between nutritional content to some yam agronomic traits.

Thirty-four sorghum (S. bicolor (L.) Moench) landraces consisting of 1020 individual plants (30 plants of each landrace) collected from five agroecological sites (ecosites) in North Shewa and South Welo regions of Ethiopia (Bati 8, Fontenina 5, Haik 2, Layignaw ataye 17 and Merewa Adere 2) were classified on the basis of 4 classifying variables: administrational zones; Woredas (smallest administrative unit), ecosite of origin and altitude. Morphological variation for the fourteen qualitative characters that showed two or more phenotypic classes were estimated using the Shanon–Weaver diversity index (H′). Phenotypic variation was found between and within each classifying variables. The value of H′ for all landraces varied from 0.32 to 0.98 with an overall mean of 0.77±0.04. One-way analysis of variance (ANOVA) showed significant differences between characters within all classifying variables and this contributed to the largest portion of the total variance. Cluster analysis based on ordinal variables grouped the landraces into five clusters. A higher proportion of landraces sharing similar altitude classes and similar ecosites were grouped together. Panicle compactness and shape as well as stalk juiciness were the predominant characters in grouping the landraces into their respective clusters. Panicle compactness and shape also contributed relatively more to altitudinal and ecological differentiation. This differential distribution of landraces with panicle types with respect to compactness and shape revealed the adaptive significance of panicle compactness and shape that reflected the patterns of distribution of different races in north Shewa and south Welo. χ2 test of all characters did not show significant differences between the frequencies of observed and expected characters.

A total of 1050 sorghum (Sorghum bicolor) and tef (Eragrostis tef) fields distributed in six study sites within north Shewa and south Welo (Central Highlands of Ethiopia) were systematically surveyed to examine the status of integration of edible oil crops into the cereal-based farming system. Farmers' criteria for, and perception on, integration between edible oil crops and the major cereals at field level as well as integration between the cereal grains and the oilseeds in food making at home were studied and analyzed based on formal semi-structured interview and informal discussion with local expert farmers as key informants. Farmers' traditional space optimization technique has been instrumental in rightly fitting edible oil crops (as intercrops and border crops) into the cereal-based system. Six species of edible oil crops are integrated (70.3%) in various proportions in fields of sorghum and tef. At least one oil crop was significantly intercropped and/or border cropped in sorghum fields. Noog (Guizotia abyssinica) and sesame (Sesamum indicum) were the most important edible oil crops of the study area having strong integration with sorghum both at field and home level. On average, noog was more frequently intercropped with sorghum (8.3%) than with tef (4.5%), while it was more frequently border cropped with tef (32.4%) than with sorghum (19%). Sorghum was more frequently inter/border cropped with sesame (39/2%) than with tef (10.1/0.5%). The stronger the integration of a given oilseed with sorghum-based foods, the higher the companionship between sorghum fields and the oil crop in the landscape. This cultural practice by farmers has positive contributions to on-farm conservation of oil crops along with tef and specific sorghum landraces. The central theme of this paper therefore converges on the issue of on-farm in-situ agrobiodiversity conservation that was shaped by successive ancestral generations and passed on to the present.

For hares (Lepus spp., Leporidae, Lagomorpha, Mammalia) from Ethiopia no conclusive molecular phylogenetic data are available. To provide a first molecular phylogenetic model for the Abyssinian Hare (Lepus habessinicus), the Ethiopian Hare (L. fagani), and the Ethiopian Highland Hare (L. starcki) and their evolutionary relationships to hares from Africa, Eurasia, and North America, we phylogenetically analysed mitochondrial ATPase subunit 6 (ATP6; n = 153 / 416bp) and nuclear transferrin (TF; n = 155 / 434bp) sequences of phenotypically determined individuals. For the hares from Ethiopia, genotype composition at twelve microsatellite loci (n = 107) was used to explore both interspecific gene pool separation and levels of current hybridization, as has been observed in some other Lepus species. For phylogenetic analyses ATP6 and TF sequences of Lepus species from South and North Africa (L. capensis, L. saxatilis), the Anatolian peninsula and Europe (L. europaeus, L. timidus) were also produced and additional TF sequences of 18 Lepus species retrieved from GenBank were included as well. Median joining networks, neighbour joining, maximum likelihood analyses, as well as Bayesian inference resulted in similar models of evolution of the three species from Ethiopia for the ATP6 and TF sequences, respectively. The Ethiopian species are, however, not monophyletic, with signatures of contemporary uni- and bidirectional mitochondrial introgression and/ or shared ancestral polymorphism. Lepus habessinicus carries mtDNA distinct from South African L. capensis and North African L. capensis sensu lato; that finding is not in line with earlier suggestions of its conspecificity with L. capensis. Lepus starcki has mtDNA distinct from L. capensis and L. europaeus, which is not in line with earlier suggestions to include it either in L. capensis or L. europaeus. Lepus fagani shares mitochondrial haplotypes with the other two species from Ethiopia, despite its distinct phenotypic and microsatellite differences; moreover, it is not represented by a species-specific mitochondrial haplogroup, suggesting considerable mitochondrial capture by the other species from Ethiopia or species from other parts of Africa. Both mitochondrial and nuclear sequences indicate close phylogenetic relationships among all three Lepus species from Ethiopia, with L. fagani being surprisingly tightly connected to L. habessinicus. TF sequences suggest close evolutionary relationships between the three Ethiopian species and Cape hares from South and North Africa; they further suggest that hares from Ethiopia hold a position ancestral to many Eurasian and North American species.

A total of 415 sorghum (Sorghum bicolor (L.) Moench) accessions representing different regions of Ethiopia, Eritrea and a group of introduced lines were evaluated for 15 quantitative characters to determine the extent and geographical pattern of morphological variation. The extent of variation was highly pronounced for agronomically important characters for sorghum. These characters included plant height, days for 50% flowering, peduncle exsertion, panicle length and width, number and length of primary branches per panicle and thousand seed weight. Significant regional variation was also observed for most of the characters. The results implied that environmental factors such as altitude, rainfall, temperature and growing period are important in regional variation. Mean for plant height and for days for 50% flowering showed clinal variation along the gradients of rainfall pattern and growing period in Ethiopia. Moreover, there were significant positive correlation coefficients between most of the characters. This included the correlation between agronomic characters of primary interest in sorghum breeding such as plant height and days for 50% flowering and also between various characters and the altitude of the collection sites. The implications of the results in plant breeding, germplasm collection and conservation as well as the probable sources of the wide range of variation are discussed.

The extent and patterns of distribution of genetic variation among 80 sorghum (Sorghum bicolor (L.) Moench) germplasm accessions from Ethiopia and Eritrea were investigated using RAPD with 20 oligonucleotide primers. The primers generated a total of 147 polymorphic bands across the 80 accessions with a mean of 7.35 bands per primer. Estimation of the extent of variation by the Shannon-Weaver diversity index revealed an intermediate level of overall variation (H = 53), although the levels varied among regions of origin of the accessions. Partitioning of the total variation revealed considerable variation (77%) within the region of origin of the accessions and the remainder (23%) among regions of origin. Similarly, a large portion (94%) of the total variation was found within the adaptation zones compared to among the adaptation zones (6%). The results suggest a weak differentiation of the sorghum material both on regional and agro-ecological bases, which could be ascribed to the high rate of outcrossing in cultivated sorghum and its free natural hybridization with its wild and weedy relatives, as well as to seed movement by humans. The average genetic dissimilarity was found to be 36% among the 80 accessions and 13% among the 15 regions of origin. Cluster analysis failed to group accessions of the same region or the same adaptation zone, which further confirmed the weak differentiation of the material studied. The clustering pattern of the regions of origin was broadly concordant with previous clustering patterns obtained using morphological characters, in which regions with broad agro-climatic conditions were grouped together.

Multivariate methods, including principal component, cluster and discriminant analyses, were used to assess the patterns of morphological variation and to group 415 sorghum accessions for 15 quantitative characters. The first five principal components explained 79% of the total variation with plant height and days to 50% flowering being the most important characters in the first principal component. Cluster analysis grouped the accessions into ten clusters. A greater proportion of accessions of similar adaptation zones and accessions from regions of origin with similar agro-climatic conditions were grouped together. Moreover, discrimination of accessions was more pronounced when discriminant analysis was based on zone of adaptation rather than regions of origin. Based on the observed patterns of variation, it is concluded that the morphological variation in the material studied is structured by environmental factors. The implications of the results for plant breeding and germplasm conservation programmes are

We present an EST library, chloroplast genome sequence, and nuclear microsatellite markers that were developed for the semi-domesticated oilseed crop noug (Guizotia abyssinica )f rom Ethiopia. The EST library consists of 25 711 Sanger reads, assembled into 17 538 contigs and singletons, of which 4781 were functionally annotated using the Arabidopsis Information Resource (TAIR). The age distribution of duplicated genes in the EST library shows evidence of two paleopolyploidizations—a pattern that noug shares with several other species in the Heliantheae tribe (Compositae family). From the EST library, we selected 43 microsatellites and then designed and tested primers for their amplification. The number of microsatellite alleles varied between 2 and 10 (average 4.67), and the average observed and expected heterozygosities were 0.49 and 0.54, respectively. The chloroplast genome was sequenced de novo using Illumina’s sequencing technology and completed with traditional Sanger sequencing. No large re-arrangements were found between the noug and sunflower chloroplast genomes, but 1.4% of sites have indels and 1.8% show sequence divergence between the two species. We identified 34 tRNAs, 4 rRNA sequences, and 80 coding sequences, including one region (trnH-psbA) with 15% sequence divergence between noug and sunflower that may be particularly useful for phylogeographic studies in noug and its wild relatives.

Comparative sequencing of >7 kb of highly variable chloroplast genome regions (atpB–rbcL, trnS–trnG, rpl22–rps19, and rps19–rpl2 spacers; introns in atpF, trnG, trnK, and rpl16) with microsatellites known from other angiosperms was carried out in Coffea . Samples comprised 8 diploid species of Coffea, 5 individuals of tetraploid C. arabica representing geographically distant wild populations from Ethiopia, 2 commercial cultivars of C. arabica, and Psilanthus leroyi and Ixora coccinea as outgroups. Phylogeny reconstruction using maximum parsimony and Bayesian inference resulted in congruent topologies with high support for C. arabica and C. eugenioides being sisters. Partitioned analyses showed that all regions except the atpB–rbcL spacer resolved this sister-group, although this was often unsupported. The large sequence data set further shows that chloroplast genomes of C. arabica and C. eugenioides each possess apomorphies, indicating that not C. eugenioides but an ancestor or close relative of C. eugenioides is the maternal parent of C. arabica. Seven variable chloroplast microsatellites were characterized in Coffea. Most microsatellites are poly(A/T) stretches, whereas one in the trnS–trnG spacer has an (AT)n motif. Most strikingly, all individuals of C. arabica possess identical sequences, suggesting a single chloroplast haplotype. This can be explained by a recent origin of C. arabica in a unique allopolyploidization event, or by severe bottleneck effects in the evolutionary history of the species. Reconstruction of the evolution of microstructural mutations shows much higher levels of homoplasy in microsatellite loci than in other parts of spacers and introns. Microsatellites are inferred to evolve by insertion and deletion of 1 to 3 motif copies in one step.

There are seven species of genus Kniphofia in Ethiopian flora. K. foliosa, K. hildebrandtii, K. insignis, K. isoetifolia , and K. schimperi are endemic. Kniphofia pumila and K. thomsonii are widespread from West Africa to Eastern and Central Africa. In this study the genetic diversity and the relationships between five endemic and one widespread Kniphofia species in Ethiopia was conducted based on isoenzymes systems. The electrophoretic analyses of four enzymes systems in the species from ten experimental sites in ten locations revealed seven putative loci, of which PGM-1, PGM-2, AAT-2 and GPI-2 were polymorphic. The species have displayed higher genetic diversity parameters than other endemic plants. The over all mean inbreeding coefficient (F) was positive indicating slight deficiency in the number of heterozygotes. The total genetic diversity varies from 0.5 in K. schimperi to 1.11 in K. isoetifolia indicating very low diversification between the populations with in a species. At the generic level HT ranges from 0.034 to 0.470 with a mean of 0.247. The genetic variation among the species (G ST ) is 6.6%. Over all mean of genetic distance (0.011) and genetic similarity (0.938) indicated high similarity among the populations. Despite morphological variation particularly in floral morphology and inflorescence architecture, the over all mean of unbiased genetic identity of the species (0.989) is much higher than described for congeneric species (I = 0.64). The results, therefore, indicate that the Ethiopian Kniphofia species share a fairly recent common ancestor, but have differentiated in floral and inflorescence character through rapid evolution. This hypothesis needs, however, further testing. Key words/phrases : Endemism, genetic diversity, isoenzyme, kniphofia, inbreeding coefficient SINET: Ethiopian Journal of Science Vol. 27 (2) 2004:143–152

Variability of grass pea landrace populations for isozymes, Oxalyl Diamino Propanoic acid ODAP) and protein contents were investigated following standard procedures to detect genetic variation. The result indicated that phenotypic polymorphism was observed for the three enzymes, the highest being for esterase. The degree of differentiation (FST) of the individual loci ranged from 0.031 (for ACP-3) to 0.784 (for AAT-2). The highest polymorphism was detected in populations collected from Gondar region indicating the need for priority germplasm collection and site selection for in situ conservation in this region. The ODAP and protein analyses also revealed presence of variability among the populations. Fortunately, four entries with low ODAP contents ranging from 0.14% to 0.18% were identified in populations collected from different regions indicating the variation of this trait within population and between regions. These lines with low ODAP content are obviously considered important for further breeding program. Key words/phrases : Ethiopia, grass pea , isozyme, Lathyrus sativus , ODAP ET: Ethiopian Journal of Science Vol. 27 (2) 2004: 153–160

The amount and distribution of genetic variation was investigated in 48 sorghum landrace accessions, representing 13 regions of origin and three adaptation zones (lowland, intermediate and highland elevation) in Ethiopia and Eritrea. Assaying 11 enzymes systems, 23 putative loci were scored for a total of 27 alleles. Nineteen loci were monomorphic and fixed for the same allele, while the remaining 4 loci, each with 2 alleles, were polymorphic across the 48 accessions. The results show significant differences in allele frequencies among the accessions, regions of origin and the adaptation zones. However, all measures of genetic variation used show that the accessions maintained much lower levels of variation than the corresponding mean values for self-pollinating crop plants, confirming previous conclusions that sorghum is depauperated in allozymic variation. The total gene diversity was 0.25, which partitioned 59% within and 41% among accessions. The latter was largely due to variation among accessions within the adaptation zones (38%), while only 3% was due to variation among accessions between the adaptation zones. Similarly, most of the total gene diversity was found within the regions of origin (80%) and within the adaptation zones (97%). Both the dendrogram constructed from NEI's unbiased genetic distance and the plot of the first two principal components distinguished three groups of regions. The level of gene flow was low among accessions, regions of origin and among accessions within adaptation zones, but high among adaptation zones. The results are discussed with emphasis on genetic resources conservation and utilization.

The study was conducted on 50 landrace populations of grass pea at Adet Research Center, Ethiopia, using randomised complete Block design in three replications to determine morphological variability and character associations. Evaluations were made on plant and yield characters from eight plants tagged randomly from each plot. The data were subjected to Analysis of Variance (anova), heritability, correlation and cluster analyses. Higher mean and cv values were recorded for most of the agronomic traits for populations collected from Gondar region and the higher altitude group (>2500 m) indicating the presence of high genetic diversity in this region and altitude group. Phenotypic coefficient of variation (pcv) was slightly higher than genotypic coefficient of variation (gcv) for all the characters studied signifying that genotypic factors exerted reasonable effect in estimating the variation. The wide difference between pcv (22.4%) and gcv (13.0%) for seed yield per plant indicated the complexity of this trait and the important role of other factors such as environment in influencing yield potential in addition to the genetic factors. The strong positive association of pods per plant, 100 seed weight and primary branches per plant with seed yield indicated the possibility of selecting lines for yield improvement based on these characters at the very early stage of the grass pea breeding program. Key words/phrases: Correlation grass pea, heritability, Lathyrus sativus, variation SINET: Ethiopian Journal of Science Vol.25(2) 2002: 191-204

The failure of faba bean production in some regions of Semien Shewa necessitated a research for a possible explanation and solution to reverse the problem. Two regions with a failure in pulse production of faba bean for five to ten years i.e.'yield-depleted' Molale and Mehal Meda, and two regions that are still capable of producing faba bean i.e. 'yield-sustained' Ankober and Keyt were selected. Comparative assessments of their nutritional factors, rhizobial type, rhizobial density, and inoculation and fertilizer treatments with respect to their soil types were undertaken. The soil analyses showed that 'yield-depleted' areas were generally characterized by a medium to high concentration of nitrogen (0.1—0.2%), a low content of phosphorus (3—6 ppm) and potassium, a high concentration of calcium and magnesium, and a lower population density of rhizobia (10 1—10 2 g-1 soil). The results also showed that shoot length, shoot dry matter, and nodule fresh weight were significantly affected (p=0.01) by soil type and different inoculation and fertilizer treatments. Although growth parameters, in general, were improved by different treatments, shoot dry matter and nitrogen contents were not significantly affected in 'yield-sustained' regions as compared to 'yield-depleted' ones. The results also showed that the comparative symbiotic effectiveness of the indigenous strains and the type exotic strain (reference strain) Tal 1397N was not different. It did not also show significant difference on the above mentioned growth parameters with different treatments. This indicates that the indigenous strains are equally effective in nitrogen accumulation provided that the problems of other limiting nutritional factors can be alleviated in the soil. This suggests that combined inoculation and fertilizer treatments can improve growth and reverse production of pulses in 'yield depleted' regions of Semien Shewa. SINET: Ethiopian Journal of Science Volume 24, No. 2 (December 2001), pp. 197-211 Key words/phrases: Faba bean, fertilizer and inoculation treatments, growth-related parameters, indigenous and exotic rhizobia, Semien Shewa

Biochemical studies of 1 1 cultivars of the Ethiopian cereal tef, Eragrostis tef (Zucc.) Trotter, and of 14 accessions of wild Eragrostis species were made by chromatography of leaf phenolics and electrophoresis of seed proteins. The data from both studies were analysed by appropriate numerical taxonomie methods and compared. Great variation was found in E. tef, and different cultivars showed similarities to several different wild Eragrostis species, suggesting the possibility of many species, particularly E. pilosa but also E. aethiopica and E. barrelieri and possibly also E. curvula and E. cilianensis, being involved in the evolution of tef. The classification of E. diplachnoides in a distinct genus, Diandrochloa de Winter, is supported.

The idea that all modern humans share a recent (within the last 150,000 years) African origin has been proposed and supported on the basis of three observations. Most genetic loci examined to date have (1) shown greater diversity in African populations than in others, (2) placed the first branch between African and all non-African populations in phylogenetic trees, and (3) indicated recent dates for either the molecular coalescence (with the exception of some autosomal and X-chromosomal loci) or for the time of separation between African and non-African populations. We analyze variation at 10 Y chromosome microsatellite loci that were typed in 506 males representing 49 populations and every inhabited continent and find significantly greater Y chromosome diversity in Africa than elsewhere, find the first branch in phylogenetic trees of the continental populations to fall between African and all non-African populations, and date this branching with the (δμ)2 distance measure to 5800–17,400 or 12,800–36,800 years BP depending on the mutation rate used. The magnitude of the excess Y chromosome diversity in African populations appears to result from a greater antiquity of African populations rather than a greater long-term effective population size. These observations are most consistent with a recent African origin for all modern humans.