Cryptic speciation in Lens culinaris

Summary Three crossability groups have been identified in the wild progenitor of lentil, Lens culinaris ssp. orientalis. The common one which is predominant in this taxon and in the cultigen, the unique one, which at present is known only from three populations in southern Turkey and northern Syria and the intermediate one, known from four populations in that general region. Crosses between members of the common and unique groups yield aborted seeds which can be rescued by embryo culture. Members of the intermediate group are cross-compatible with both other groups. Crossability potential seems to be controlled by a few major genes and minor genes of quantitative nature. One population of the unique group is characterized by novel karyotype and chromosome rearrangements and is reproductively isolated from any other population of Lens culinaris. The implication of the three crossability groups and the novel chromosome rearrangement for lentil taxonomy are briefly discussed.     

小麦-长穗偃麦草矮秆种质系的鉴定及遗传分析

矮源是进行小麦矮化育种的基础。本研究对2个小偃麦矮秆种质系31505-1和31505-2进行了分子鉴定和遗传分析。结果表明,31505-1和31505-2是2个不同的矮秆小偃麦易位系,31505-1中易位的偃麦草染色体片段位于2D染色体;对矮秆小偃麦种质系与不同株高材料杂交后代的株高和节间长度进行了分析,发现2个种质系的后代致矮率可达16%~23%,其株高的降低主要由节间长度的变化引起的,其中倒2节间与株高的变化相关性最高。本研究对拓宽小麦矮秆种质资源基础具有一定意义。     

植物形态建成基因:遗传操作提高作物产量的靶标

本文主要论述作物矮化基因和分蘖相关基因的研究进展 ,以及这些基因作为遗传操作的分子靶标在增加粮食产量方面的重要应用价值。     

Geographical, altitude and agro-ecological differentiation of isozyme and hordein genotypes of landrace barleys from Ethiopia: implications to germplasm conservation

An analysis of the variability of genes encoding six isozyme systems (15 loci) and two storage proteins (2 loci) in landrace barley from Ethiopia is reported. The materials consisted of populations collected from sites as low as 1650 and as high as 3750 meters, covering a wide range of agro-ecological conditions and geographical areas. Of the 17 loci 7 were polymorphic and 10 monomorphic when the 95% criterion of polymorphism was applied. Despite the disproportionate monomorphic loci, polymorphism was detected in all populations when this criterion is used. The populations were found to possess fairly low mean number of alleles per locus (A = 1.5), low mean value of expected heterozygosity (H = 0.134) and a fairly high mean percentage of polymorphic loci (P = 35.3%). The mean F_ST= 0.474 for the populations is typical of inbreeding species. The result indicated that allelic richness is concentrated in altitude class 3 (2500–3000 m) followed by altitude class 1 (<2000 m). Altitude class 2 (2000–2500) holds an intermediate place though it is the highest in terms of expected heterozygosity (H = 0.245). Higher genetic diversity is concentrated in some geographical regions such as Shewa, Arsi, Bale compared to others (Welo, Gamu Gofa, Gojam). Genetic differentiation among the agro-ecological zones was more profound than both among the altitudes and among regions. Correlation analysis between phenotypic diversity (Shannon-Weaver diversity index) and expected heterozygosity (H) for isozyme/hordein loci revealed non significant associations except with respect to agro-ecological zones. In general, it was detected that sites in highland areas in central and northern regions may be more desirable for in situ conservation than sites in peripheral regions in terms of isozyme/hordein diversity and current rate of varietal replacement.     

Interspecific relationship and genetic diversity in wild beets in section Corollinae genus Beta: Isozyme and RAPD analyses

Interspecific relationship among wild beets in section Corollinae was analyzed. Isozyme allele composition supports the concept of three basic species consisting of two diploid species, Beta lomatogona and Beta macrorhiza and the tetraploid species, Beta corolliflora. The polyploid and apomictic species referred to as Beta trigyna and Beta intermedia were found as hybrids. Based on isozyme and RAPD results, B. corolliflora was also found more related to B. macrorhiza than to B. lomatogona. From the phylogenetic trees constructed from isozyme data, B. corolliflora and B. macrorhiza seem to be the end members of the evolutionary line. Analysis of genetic diversity showed that B. corolliflora was more polymorphic and heterozygous than B. lomatogona and B. macrorhiza. Differences between B. macrorhiza accessions from Turkey and Dagestan were found.     

东乡野生稻原位圃遗传多样性的微卫星标记分析

遗传多样性的分析是收集与利用种质资源的重要前提。利用微卫星标记对113份东乡野生稻(Oryza rufipogon Griff.)(简称"东野")进行多样性分析,24对SSR引物共得到114个等位基因,平均每对引物得到4.75个,表明东野具有丰富的遗传多样性。聚类分析表明,东野群体内来自同一居群的部分材料遗传距离较近,3个居群中有2个居群最小遗传距离为0,1个居群最小遗传距离为0.018,但也有些材料间的遗传距离很大,最大达0.851。东野3个居群居群内的平均遗传距离为0.171~0.435,居群间的平均遗传距离为0.432~0.652,表明东野群体内的遗传变异以居群间为主,因此必须对东野原生地的现有居群实行有力的保护。     

Genetic diversity in grasspea (Lathyrus sativus L.)

Genetic diversity was investigated in 348 accessions and subaccessions of grasspea (Lathyrus sativus L.) from 10 geographical regions. Polymorphism for 20 isozymes of 13 enzyme systems was studied to estimate the genetic diversity. The Near East and North Africa regions included the most variability for these isozyme systems, suggesting that the center of diversity (center of origin) for grasspea is in this general area. The lowest variability was found in accessions and subaccessions from South America, followed by those from Sudan–Ethiopia. Diversity was measured for individual loci over regions and EST-1 and SKDH had the highest genetic diversity. The closest genetic diversity was observed for LAP-2, followed by AAT-1 and PGM. The closest genetic distance existed between populations from the Near East and North Africa. Populations from South Asia and Sudan–Ethiopia, though geographically widely separated, exhibited a closer genetic distance from each other than from other regions.     

Genetic diversity in European accessions of the Barley Core Collection as detected by isozyme electrophoresis

Genetic diversity in 79 European accessions of the Barley Core Collections was surveyed using isozyme electrophoresis. A total of 26 alleles were observed at the ten isozyme loci. All loci were polymorphic except Pgd-1 which was monomorphic. The comparison of the results with those of previous studies indicates that most of the alleles occurring in the European Barley are also observed in this set of the European Barley Core Collections. Only five alleles (Est-1 Al; Est-5 Ag, Te; Pgi-1 C and Ndh-2 B) were absent. Nine of 26 alleles were rare alleles, which were detected only in one or two accessions. Moreover, most of rare alleles were detected in 6-rowed winter barley. It is very important to include rare alleles for maximising the genetic variations in core collections. In the set of European Barley Core Collection, 6-rowed barley contained larger diversity than 2-rowed barley; winter type contained larger diversity than spring type. The cluster analysis separated 79 accessions into three major groups. Group I is more complex and comprised 2-rowed spring, 2-rowed winter and 6-rowed winter barley. In this group, 18 accessions in the cluster A and 14 accessions in the cluster B possessed identical genotypes as judged from the ten isozyme data. Principal coordinate analysis could not clearly separate the spring cultivars from the winter barley lines, as well as not separate 2-rowed from 6-rowed barley.     

Genetic diversity in wild cereals: regional and local studies and their bearing on conservation ex situ and in situ

The current alarming global crisis and extinction of biodiversity affect negatively the planet's biosphere. Conservation of biodiversity is one attempt to alleviate the pending extinction of the biosphere by humans. Genetic diversity, the basis of evolution by natural selection, is gravely threatened in the progenitors of cultivated plants and its exploration, evaluation, conservation in situ and ex situ is imperative to guarantee sustainable development. This is illustrated by the population genetics and ecology of two important progenitors of cereals wild, wheat and barley. The wild cereals are rich in adaptive genetic diversity in the Fertile Crescent, primarily in Israel, which is their center of origin and diversity. The 40–55% intrapopulation diversity level in the wild cereals contrasts sharply with the average of 80% in outbreeders. Genetic diversity in wild wheat and barley is structured, particularly in wild emmer wheat, as an 'archipelago' ecological and genetic structure. These include central, semi-isolated and ecologically peripheral and marginal isolated populations, where specific alleles and allele combinations predominate as coadapted blocks of genes, adaptive to diverse ecological stresses. These involve both physical (climatic and edaphic) and biotic (pathogens and parasites) stresses at macro- and microgeographical scales. Complementary in situ and ex situ conservation is imperative across the geographic range of these species, to safeguard their immensely important genetic resources for crop improvement.     

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.     

植物铝抗性基因及抗铝毒基因工程研究进展

酸性土壤占世界可耕作土壤的30％,而铝毒是酸性土壤中植物生长和作物生产的主要限制因素.近年来,在植物中鉴定了一系列抗铝基因,如有机酸通道蛋白基因(ALMT1和MATE),ABC通道蛋白基因(STAR1和STAR2)和转录因子基因(STOP1和ART1).通过基因工程手段在植物中过表达有机酸通道蛋白基因、有机酸代谢酶基因和其他铝胁迫响应基因均获得了很大的进展.本文综述了植物抗铝基因的克隆与鉴定,以及通过遗传操作提高植物的抗铝能力.     

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.     

Genetic variability of Coffea arabica L. accessions from Ethiopia evaluated with RAPDs

The genetic diversity of 50 wild and semi-wild accessions of the Coffea arabica L. germplasm collection, gathered by the FAO and ORSTOM missions to Ethiopia, and maintained in Colombia by CENICAFE, was evaluated with RAPD markers. The evaluation was carried out in two phases: In phase one, the polymorphism of 8 Ethiopian accessions of different geographic origin, plus the cultivated variety 'Caturra' was assessed with the RAPD technique with forty-two 10-mer oligonucleotides. In phase two, 51 accessions were assessed with a set of 5 polymorphic primers that reproduced, with a correlation of 95%, the groups generated by the 24 polymorphic primers found in phase one. Principal Coordinate Analysis of molecular data revealed that a closely related group consisting of 86% of the Ethiopian C. arabica accessions evaluated are significantly different from the Caturra variety and could be used in a genetic breeding initiative to increase the variability of cultivated varieties. The results also indicate that a larger polymorphism is present in the Colombian replica of FAO Ethiopian coffee germplasm collection than previously reported.     

Genetic relationships within Vigna unguiculata (L.) Walp. based on isozyme analyses

Summary Isozyme analyses of genetic diversity in Vigna unguiculata were performed to determine genetic relationships and level of genetic diversity between wild and cultivated cowpea. Thirty-four cultivated accessions of V. unguiculata, 56 wild accessions of V. unguiculata, and six accessions representing five related wild Vigna species were analyzed. Ten enzyme systems were polymorphic within Vigna unguiculata: AAT, ACO, G6PDH, DIAP, LAP, MUE, ME MDH, PRX, and SOD. Fourteen of 24 putative loci (58%) were polymorphic within wild V. unguiculata, but only one locus (4%) was polymorphic within cultivated cowpea; when five related Vigna species were examined, 21 of the 24 bands of activity showed polymorphisms (88%) adding 33 alleles to the 48 identified within V. unguiculata. In one F₂ population of 68 plants (UCDVg 36 × UCDVg 21) a loose linkage was indicated between Diap-2 and G6pd-1 (² = 15.39; p = 0.004) with an estimated distance of 36.0 cM ± 5.02 (recombination (r) = 0.31). Also in another F₂ population of 38 plants (CB 88 × UCDVg 21) a loose linkage was indicated between Lap-1 and Prx (\gC² = 9.62; p = 0.047) with an estimated distance of 39.8 cM ± 7.0 (r = 0.33). Total genetic diversity (H_T) was 0.085 over all of the accessions including the one classified as V. nervosa. Within accession diversity (H_s) approached zero and between accession diversity (D_si) was responsible for all of the genetic diversity present. Therefore the coefficient of gene differentiation (G_ST = D_STII_T) approached 1. Absolute gene differentiation (D_m) was 0.087. Two of the nine segregations in this study were skewed. In general, results of this study concurred with the taxonomic classification within V. unguiculata and provided a strong indication that a severe genetic bottleneck occurred during the domestication process of cowpea.Abbreviations AAT aspartate amino-transferase - ACO aconitase - ALD aldolase - AUS Australia - BDI Burundi - BWA Botswana - CHN China - CMR Cameroon - DIAP diaphorase - DZA Algeria - ETH Ethiopia - G6PDH glucose-6-phosphate dehydrogenase - GDH glutamate dehydrogenase - GHA Ghana - GUY Guyana - IDH isocitrate dehydrogenase - IND India - KEN Kenya - LAO Laos - LAP leucine aminopeptidase - MDH malate dehydrogenase - ME malic enzyme - MEX Mexico - MOZ Mozambique - MUE methylumelliferyl-esterase - MWI Malawi - MYS Malaysia - NER Niger - NGA Nigeria - PRX peroxidase - RBSC ribulose-bisphosphate carboxylase - SEN Senegal - SLE Sierra Leone - SOD superoxide dismutase - TGO Togo - TZA Tanzania - USA United States of America - XDH xanthine dehydrogenase - ZAF South Africa - ZAR Zaire - ZIM Zimbabwe - ZMB Zambia     

Genetic erosion of sorghum (Sorghum bicolor (L.) Moench) in the centre of diversity, Ethiopia

The Ethiopian region is characterised by a wide range of agro-climatic conditions, which accounted for the enormous resources of agro-biodiversity that exist in the country. The most important of these resources is the immense genetic diversity of the various crop plants in the country. Of these, one of the most on farm genetically diverse crops is sorghum. Since the advent of formal breeding in particular after green revolution, genetic diversity of most crops has been threatened worldwide. In order to assess on farm genetic erosion (GE), various research methodologies were employed. These were focused group interviews with 360 farmers, on farm monitoring and participation with 120 farmers, key informant interviews with 60 farmers and development agents, and semi-structured interviews with 250 farmers. Besides, diversity fairs were done with over 1200 farmers. Notwithstanding the complexity of assessing GE, it was assessed by various methods; namely, by temporal method (comparing 1960 and 2000 collections), area method, and semi-structured interview method at individual, community or wereda level and causes of varietal loss from other various perspectives. Farmers perceived GE as the reduced importance of the variety as indicated by lower proportion in the varietal portfolio. The five most important factors for varietal loss at individual farmers’ level were reduced benefit from the varieties, drought, Khat expansion, reduced land size and introduction of other food crops respectively. GE was not affected by wealth groups and ecological regions. Farmers do not make simple replacement as a strategic mechanism for genetic resources management. GE at regional level was quantified by temporal and spatial method. There was a complementation not rivalry between farmer varieties (FVs) and improved varieties (IVs). The whole process of GE is explained by three models, namely: Bioecogeographic enhanced genetic erosion model, Farmer induced genetic erosion model and Farmer-cum-bioecogeographic genetic erosion model. As aforementioned, sorghum genetic erosion behaviour is completely different from other food crops such as tetraploid wheat. The prediction in the late seventies that complete erosion of FVs by IVs by the end of the eighties, the principle of GE that competition between IVs and FVs, favours the former and results in the replacement of the latter is not valid in the context of sorghum in Ethiopia. Hence, maintenance of the on farm genetic diversity of sorghum is a reality but GE is rhetoric.     

橘小实蝇不育雄虫与野生雄虫间遗传分化

对橘小实蝇不育雄虫和福建7个不同地区的野生雄虫共37个个体的线粒体细胞色素氧化酶I（mtDNA COI）基因进行了部分序列测定。在获得的650bp序列中,共有72个变异位点、32个单倍型,其中共享单倍型3种;对所有单倍型聚类分析发现,单倍型在系统树中的分布散乱,没有显示出明显的地理分布族群;结合遗传变异指数（Fst）和净遗传距离（Da）分析认为橘小实蝇不育雄虫与野生虫源间、不同来源的野生虫源间已存有一定程度的遗传分化,但分化程度较低。研究认为应用昆虫不育技术防治橘小实蝇,在饲养过程中需针对不同防治区引进野生虫源复壮,以确保不育雄虫和野生虫源相匹配,提高防治效果。     

Local Organizations Involved in the Conservation of Crop Genetic Resources: Conditions for their Emergence and Success in Ethiopia and Kenya

Local organizations comprising of farmers, local formal and informal institutions, and public conservators can potentially be relevant options to confront the challenges of conserving indigenous crop varieties in developing countries. Although property rights and market failure problems experienced in crop genetic resources (CGRs) are different from other natural resources such as forests, wildlife, etc., such local organizations, and contractual arrangements within them, can be very instrumental in enhancing on-farm conservation. However, empirical investigations of such local organizations in order to determine the dimensions of their feasibility have been scarce. Against this background, this paper analyzes interactions of stakeholders in these local organizations and then explores the conditions for their emergence and success. The paper discusses field cases of on-farm conservation of traditional cereals and pulses from Ethiopia and indigenous vegetables from Kenya. It points out that local organizations conserving CGRs can be classified into different categories of contractual arrangements depending on certain driving factors that influence interactions of stakeholders and devolvement of decision-making authority. The paper further argues that these driving factors, which include accessibility to markets, presence of collective action or self-organizational capacity and provision of relevant CGRs conservation policies, form some of the key conditions determining the success of the case study organizations. The paper concludes by outlining policy implications on the structuring of such local organizations and the importance of certain factors in facilitating their emergence and success.     

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.     

Comparative analysis of seed morphometric and allozyme data among four populations of neem (Azadirachta indica)

The objectives of this study were to determine the patterns of variability and to compare genetic distance between seed morphometric and allozyme data of neem (Azadirachta indica). Phenotypic variation from open pollinated seed materials at 12 isozyme loci was examined using starch gel electrophoresis for four populations from Thailand, Bangladesh and Kenya. All four populations exhibited high levels of variation for seed parameters and isozymes. UPGMA cluster analysis of Nei's genetic distance when based on isozymes revealed two genetic groups. The population from Kenya showed a close genetic relationship with the Bangladeshi populations. The population from Thailand exhibited a distant relationship with the other three populations. This result suggests that the Kenyan population was introduced from the Indian subcontinent. In contrast, cluster analysis of seed morphometric data indicated three different groups of populations. The population from Kenya showed a distant relationship with all other populations. The study demonstrates that allozyme data may not correspond with morphometric traits when measuring genetic distance. It is suggested that this controversy may depend on environmental influence on morphometric traits, possibly also on the enzyme patterns.     

桂林地区蜈蚣蕨群体遗传多样性及与南宁地区群体的对比分析

采用等位酶电泳技术,研究了桂林地区的桂林市、雁山镇、永福县的野生蜈蚣蕨群体的遗传多样性,并与南宁地区群体进行比较。所测定的酶系统包括：氨基肽酶（AMP）、还原型辅酶Ⅰ心肌黄酶（DIA）、异柠檬酸脱氧酶（IDH）、苹果酸脱氨酶（MDH）、6-磷酸葡萄糖酸脱氢酶（PGD）、磷酸葡萄糖异构酶（PGI）、磷酸葡萄糖变位酶（PGM）和莽草酸脱氧酶（SKD共8个酶系统,15个酶位点。分析结果表明：桂林地区蜈蚣蕨群体内遗传多样性水平中等偏上,每个位点的等位基因平均为1．7,多态位点百分数为60％,平均期望杂合度为0．251,略高于南宁地区。