Patterns of morphological diversity in tetraploid wheat (Triticum turgidum L.) landraces from Ethiopia

Thirty‐four tetraploid (2n = 4x = 28) wheat (Triticum turgidum L.) landrace populations collected from four regions in Ethiopia, and consisting of 4099 entries were characterized for glume colour, glume pubescence, beak awn, seed colour and spike density. The main objective was to analyse the diversity and distribution of these traits on the basis of administrative regions and altitudinal gradients. The Shannon‐Weaver Diversity Index (H') was used to estimate the magnitude of diversity. With the exception of spike density, all characters were polymorphic in all regions and most altitude groups. However, clinal patterns were observed in only a few cases. At the population level, the mean H’ varied from completely monomorphic (H’ = 0.00) to highly polymorphic (H’ = 0.80 ± 0.07). The highest diversity was found in regions with relatively better climatic conditions and in optimal altitude ranges. On country basis, seed colour (H’ = 0.98) and spike density (H’ = 0.43) displayed the highest and the lowest diversity indices, respectively. Spike density was the only character that exhibited significant differences (P<0.01) both “between regions”; and “between altitude groups”;. Across characters, most of the variance was due to the lowest hierarchy, the “within‐population”; component. The “between region”; and “between altitude group”; variances were significant, but spike density alone was responsible for the differences. The overall mean H’ for Ethiopia was 0.77 + 0.09 and did not seem to have reduced appreciably within the past 25 years or so, when compared to previous estimates.     

Genetic diversity in Ethiopian barley in relation to altitude

Summary A representative sample of the Ethiopian barley collection, maintained at the Ethiopian Plant Genetic Resources Centre (PGRC/E), was studied for its phenotypic diversity for some agronomic characters, i.e. kernel row number, spike density, spikelets per spike, caryopsis type, kernel colour, thousand grain weight, days to maturity and plant height. The diversity was estimated by using the Shannon-Weaver diversity index (H) for each of the characters to examine overall genetic divergence between accessions on the basis of administrative regions, ecogeographical zones as well as altitudinal ranges within Ethiopia. Most of the variation was due to differences among characters and only a relatively small fraction due to differences between regions. However, almost all characters are considerably influenced by altitude within the regions. The mean diversity index for all characters increases with altitude, reaches a maximum between 2,400 and 2,800 m, and decreases beyond that altitude.     

Pattern analysis of the diversity of morphological plant attributes and herbage yield in a world collection of white clover (trifolium repens L.) germplasm characterised in a summer moisture stress environment of Australia

Information on the variation available for different plant attributes has enabled germplasm collections to be effectively utilised in plant breeding. A world sourced collection of white clover germplasm has been developed at the White Clover Resource Centre at Glen Innes, New South Wales. This collection of 439 accessions was characterised under field conditions as a preliminary study of the genotypic variation for morphological attributes; stolon density, stolon branching, number of nodes, number of rooted nodes, stolon thickness, internode length, leaf length, plant height and plant spread, together with seasonal herbage yield. Characterisation was conducted on different batches of germplasm (subsets of accessions taken from the complete collection) over a period of five years. Inclusion of two check cultivars, Haifa and Huia, in each batch enabled adjustment of the characterisation data for year effects and attribute-by-year interaction effects. The component of variance for seasonal herbage yield among batches was large relative to that for accessions. Accession-by-experiment and accession-by-season interactions for herbage yield were not detected. Accession mean repeatability for herbage yield across seasons was intermediate (0.453). The components of genotypic variance among accessions for all attributes, except plant height, were larger than their respective standard errors. The estimates of accession mean repeatability for the attributes ranged from low (0.277 for plant height) to intermediate (0.544 for internode length).Multivariate techniques of clustering and ordination were used to investigate the diversity present among the accessions in the collection. Both cluster analysis and principal component analysis suggested that seven groups of accessions existed. It was also proposed from the pattern analysis results that accessions from a group characterised by large leaves, tall plants and thick stolons could be crossed with accessions from a group that had above average stolon density and stolon branching. This material could produce breeding populations to be used in recurrent selection for the development of white clover cultivars for dryland summer moisture stress environments in Australia. The germplasm collection was also found to be deficient in genotypes with high stolon density, high number of branches, high number of rooted nodes and large leaves. This warrants addition of new germplasm accessions possessing these characteristics to the present germplasm collection.     

Exploiting the diversity of barley landraces in Ethiopia

The paper describes a methodology to incorporate the collection of barley landraces available in the Plant Genetic Resources Centre of Ethiopia (PGRC/E), as well as future collections, in the Ethiopian barley breeding program. Six hundred pure lines extracted from thirty Ethiopian barley landraces were evaluated and selected, along with the original populations, between 1989 and 1993. Three lines were identified which significantly outyielded the local landrace in some of the testing sites and had a higher average yield across sites and seasons. The yield of these lines was similar to the best improved variety also developed from a landrace population. Despite the relatively small number of landrace-lines (600) in the original population, the exploitation of the diversity existing within Ethiopian barley germplasm has produced in only five years promising lines for yield at low input conditions and for disease and insect resistance. Some lines had a yield potential comparable with the best breeding lines produced earlier, and one is under multiplication for release.     

Patterns of morphological and allozyme variation in sorghum landraces of Northwestern Morocco

Patterns of variation in inflorescence and spikelet morphology and in allozyme markers were studied within and among six fields of sorghum sampled from different areas in Northwestern Morocco. Substantial variation for both types of markers is found within fields. Significant differentiation among fields occurs for both types of traits, with 63% of morphological variation and 20% of allozyme variation expressed among fields. Discrepancies between allozyme studies based on germplasm accessions conserved ex situ and this and other studies involving in situ sampling underline the need to use appropriate sampling schemes for assessing the patterns of genetic variation of local landraces.     

Genetic diversity analysis and character associations in black cumin (Nigella sativa L.) based on agro-morphological and phytochemical traits

Black cumin (Nigella sativa L.) is one of the important medicinal plants that used in food and pharmaceutical industries. In the present study, 32 Iran endemic black cumin genotypes were evaluated through randomized complete block design with three replications in 2016 and 2017 growing seasons to determine the extent of genetic diversity and character associations for agro-morphological and phytochemical traits. Results showed the significant differences between genotypes for all traits studied. Clustering analysis using agro-morphological and phytochemical traits grouped genotypes into the two distinct groups. The values of percentage of essential oil and fatty oil content varied from 0.65 to 0.1.36% and 25.30% to 35.02% between genotypes, respectively. The highest seed yield and fatty oil yield obtained for Arak genotype. GC and GC/MS analyses of essential oil and fatty oil compositions of the Arak genotype revealed that p-cymene and linoleic acid were main components, respectively. Stepwise regression analysis revealed that shoot dry mass, days to ripening and seed length were the most important traits associated with seed yield, fatty oil yield and essential oil yield. Hence, these traits can be considered as important indicators for early selection for seed yield and quality in black cumin breeding programs.     

Self-incompatibility reactions in wild species of the genusBeta and their relation to taxonomical classification and geographical origin

Summary The expression of self-incompatibility (SI) rejection patterns in 29 accessions of wildBeta species was studied at the anatomical level. Three different SI-related pollen tube rejection patterns were observed: (1) The pollen germinate from many pores and the pollen tubes are very short, often with swollen tips. (2) The pollen germinate and grow along the stigmatic papillae, where the self-incompatibility response takes place at the basis of the stigmatic papillae. (3) The pollen germinate and the pollen tubes grow with a distinct direction towards the style; the self-incompatibility response is observed at the border between the stigma and the style. In general the patterns observed inB. vulgaris L. subsp.vulgaris sensu lato seem to be in accordance with an ongoing microevolutionary process that has given rise to the largemaritima complex (viz.B. trojana Pamuk?uoğlu,B. atriplicifolia Rouy, andB. maritima (L.) Arcangeli), in which it seems that the variation is related to geographical origin. The data support the idea that the endemicB. vulgaris subsp.adanensis (Pamuk?uoğlu) Ford-Lloyd & Williams forms a distinct, self-compatible group separated from themaritima complex and also thatB. macrocarpa Gussone should be retained as a separate self-compatible species. For the sectionCorollinae Ulbrich the rejection patterns are in accordance with a division into two subsections (viz.,Lomatogonae andTrigynae) previously suggested on the basis of phenotypical and molecular data. The results fromProcumbentes Ulbrich are interpreted as evidence forB. procumbens Smith andB. webbiana Moquin being more related to each other than toB. patellaris Moquin, reflecting also a similar taxonomic relationship.     

Analysis of genetic diversity of soybean germplasm from five different origins using RAPD markers

The pattern of genetic diversity among 92 genotypes of soybean from 5 different origins/sources (Pakistan, the USA, Asian Vegetable Research Development Centre (AVRDC), Japan and North Korea) was analyzed using randomly amplified polymorphic DNA markers. Out of 20 random primers 6 tested, 10 were polymorphic among genotypes and they yielded 107 markers, with an average of 10.7 markers per primer. The proportion of polymorphic bands within genotypes ranged from 0.47 to 0.71 with an average of 0.59. Pakistani and US genotypes exhibited the highest number of polymorphic bands (95%), while North Korean genotypes revealed the lowest (60%). The mean band frequency of the primers among genotypes was 0.57 with a range of 0.08–0.99. The Shannon’s index and Nei’s genetic diversity index revealed that primer OPF-06 showed maximum genetic diversity among the genotypes. Dendrogram constructed using Unweighted Pair Group Mean Average (UPGMA) method divided the genotypes into 5 main groups consisting of 13 clusters. The results of cluster analysis indicated that the genetic diversity between Pakistani and US or AVRDC genotypes is much larger than that between Pakistani and North Korean or Japanese genotypes. The Pakistani genotypes had distinct bands from plant introductions. Therefore, the Pakistani genotypes may be useful to soybean breeders.     

Expedition to the south-western Hissar Mountains (Southern Uzbekistan) for collecting plant genetic resources in 1995

A joint exploring mission has been carried out by staff members of the Institute of Botany of the Uzbek Academy of Sciences, Takent and the Institut für Pflanzengenetik und Kulturpflanzenforschung, Gatersleben, in July/August 1995 to study plant genetic resources in a remote mountainous area of south-western Hissar, Uzbekistan. Subsistence farmers of the Tupalang basin are still growing a great number of landraces and local varieties, which could be investigated for the first time in that area. In total 238 accessions, mainly of cereals, vegetables, pulses, spices and medicinal plants, were collected. Of special interest has been indigenous material of wheat, barley, turnip, chickpea, pea, lentil, small-seeded linseed as well as some wild spices and medicinal plants.     

Genetic variation of five species of Trifolium L. from south-west Turkey

Following a legume collection mission to south-west Turkey in 1996, five species of Trifolium were analysed for genetic variation within and between species in eleven morphological and flowering characters. The five species included two outcrossing species, T. michelianum and T. resupinatum, and three inbreeding species, T. clypeatum, T. glomeratum and T. tomentosum. The genetic diversity found was related to climate and edaphic factors. All five species showed significant amounts of genetic differentiation between sites and the species could be separated morphologically by principal components analysis and cluster analysis. The most significant source of genetic variation was found to be related to geographical distribution with those species which were widely distributed across south-west Turkey exhibiting much greater amounts of genetic variation between sites, than those which had a narrow distribution. The breeding system was found to be less important, but only the morphology of the outbreeding species showed any environmental clines in relation to climate. A multiple regression analysis was computed to estimate the effect of growing season on the days to flowering of each of the species.     

Isozyme diversity and analysis of the mating system of the wild rice Oryza latifolia Desv. in Costa Rica

Oryza latifolia is the most abundant and widespread wild relative of rice in the lowlands of Costa Rica. It also has the most diverse morphology. However, little is known about the genetic diversity and mating system of this allotetraploid species. Genetic analyses of nine populations from different life zones from the Pacific and Atlantic slopes were performed using six isozyme loci. Differences in genetic variability were observed among populations, of which Palo Verde and Santa Rosa were the most diverse. Most Atlantic populations clustered together, and a similar result was obtained with the Pacific populations. High levels of interpopulation diversity were observed while most populations were monomorphic for at least one genotype, suggesting little genetic flow within populations. Even in polymorphic populations no variation was observed within progeny groups, combined with Hardy-Weinberg disequilibria in most populations, commonly observed in autogamous species or in species with clonal reproduction. However, the high frequency of heterozygous-like patterns may suggest that the reproductive system of O. latifolia might be more complex. Future research may explain the genetic patterns as well as the reproductive biology of this species. The knowledge of the genetic diversity and mating system of O. latifolia could contribute to the implementation of genetic resource conservation strategies and gene flow analyses, as well as of breeding programs for rice improvement.     

Phenotypic diversity of Ethiopian grass pea (Lathyrus sativus L.) in relation to geographical regions and altitudinal range

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.     

Conserving the genetic resources of crop wild relatives in European Protected Areas

European native plant diversity is currently suffering erosion and extinction and thus, it is crucial to improve conservation strategies to maintain this essential resource. If unchecked, this genetic erosion and species extinction will cause unnecessary and irreversible harm to the economy and social well being of Europe. Much plant biodiversity is undoubtedly found in the existing 9654 European protected areas that cover 1,066,358 km², but clearly targeted and active conservation of priority plant species is required within these protected areas. To help ensure more efficient long-term sustainable conservation, a novel approach to the in situ conservation of European plants, notably crop wild relatives, is suggested. The purpose of this approach is to know what plant genetic resources (PGR) we have, where they are located and to assess whether the current network of protected areas includes a representative sample of European PGR diversity. The generation of in situ conservation and management plans for PGR populations in existing protected areas can significantly improve the present conservation status. Additionally, the identification of gaps of certain PGR in current protected areas can provide the basis for the designation of new complementary PGR in situ reserves.     

The pattern of genetic diversity in faba bean collections from Ethiopia and Afghanistan

Summary The pattern of genetic diversity in 106 faba bean accessions from Ethiopia and Afghanistan was analysed. Eight quantitative characters were observed. Differences among origins were highly significant for plant height and yield characters. Principal component analysis and cluster analysis were performed in order to ascertain phenotypic similarities between accessions, which could be useful for sampling in subsequent studies. A core of 21 accessions based on clusters which are assumed to represent a great diversity was defined.     

Multivariate analysis of morphological variation in sorghum (Sorghum bicolor (L.) Moench) germplasm from Ethiopia and Eritrea

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 arediscussed.     

Ecological correlates of RAPD DNA diversity of wild barley, Hordeum spontaneum, in the Fertile Crescent

Genetic variability in RAPDs (Randomly Amplified Polymorphic DNA) was studied in 104 genotypes of wild barley, Hordeum spontaneum from 21 populations sampled in Israel, Turkey and Iran, seven population from each country. The band (= loci) frequencies were calculated for each population and correlated with ecogeographical variables. In general, high RAPD genetic diversity indices were associated with stressful environments, either with hot or cold steppes and deserts. Interpopulational genetic distances showed no association with the geographic distance between the populations' provenance. Significant Spearman rank correlations between RAPD band frequencies and ecogeographical parameters of provenance occured. Frequencies of RAPD bands were significantly correlated with the principal component factors of allozymes. The correlation data indirectly suggest that natural selection appears to be the major determinant of both RAPD and allozyme diversities both being correlated with environmental stress.     

农牧交错区地形土壤因子与植物群落关系研究——以丰宁小坝子为例

对河北丰宁小坝子地区沙地植被恢复过程中植物与土壤环境性质进行了研究,选取15个指标,分别代表植被群落、地形因子和土壤性质。利用多元统计方法,对选取的指标进行了主成分分析和典范相关分析。结果表明沙漠化地区在植被恢复初期的植物多样性较低,土壤环境因子与物种多样性存在相关性,植被、地形和土壤因子相互影响:植被特征影响土壤理化性质的动态变化,反过来地形和土壤性质影响植被的分布和数量以及群落的结构。多元统计结果显示,地形、土壤养分与水分表现出较大的因子贡献率。不同因子指标集团的典范相关分析表明,坡位影响植被盖度,物种丰富度与土壤理化性质关系密切。     

Distribution and diversity of wildlife in northern Kenya in relation to livestock and permanent water points

Arid rangelands host a variety of drought-tolerant wildlife species, many of them requiring conservation efforts for the survival of their populations. The development of drinking water sources for people and livestock forms one of the main development interventions in these rangelands. However, the impact of availability of permanent drinking water on wildlife remains unknown. In this study we analyzed the distribution of wildlife and livestock in northern Kenya in relation to distance to permanent water. Livestock were concentrated in areas close to permanent water, while wildlife were frequently farther away from water; their distributions were inversely correlated. In addition, wildlife assemblages were more diverse farther from water. These results suggest that livestock and human activities related to water points negatively affect the distribution of wildlife.