Morphological characterization of seeds of three Australian wild Citrus species (Rutaceae): Citrus australasica F. Muell., C. inodora F.M. Bailey and C. garrawayi F.M. Bailey

The comparative morphology of the seeds of three Australian Citrus species, C. australasica C. inodora and C. garrawayi, was studied. Their seed characteristics were broadly similar to those of the cultivated species of the genus, when observed under light and scanning electron microscopy. Citrus garrawayi differed in seed shape (rounded to triangular) and seed coat morphology (i.e., thicker with longer epidermal protrusions) from C. australasica and C. inodora (rounded surface with flat underside in shape). The well-developed minute epidermal protrusions on the seed coat of C. garrawayi were more similar to those in the cultivated species, C. × sinensis and C. × aurantium. In contrast, the surface topography of C. australasica and C. inodora seeds was more like that of the cultivated species, C. × aurantifolia and C. × limon. Seed morphology, especially surface topography, was found to be a useful tool for taxonomic identification in Australian wild citrus.     

Analysis of Genetic Diversity in the Brassica napus L. Gene Pool Using SSR Markers

Genetic diversity throughout the rapeseed (Brassica napus ssp. napus) primary gene pool was examined by obtaining detailed molecular genetic information at simple sequence repeat (SSR) loci for a broad range of winter and spring oilseed, fodder and leaf rape gene bank accessions. The plant material investigated was selected from a preliminary B. napus core collection developed from European gene bank material, and was intended to cover as broadly as possible the diversity present in the species, excluding swedes (B. napus ssp. napobrassica (L.) Hanelt). A set of 96 genotypes was characterised using publicly available mapped SSR markers spread over the B. napus genome. Allelic information from 30 SSR primer combinations amplifying 220 alleles at 51 polymorphic loci provided unique genetic fingerprints for all genotypes. UPGMA clustering enabled identification of four general groups with increasing genetic diversity as follows (1) spring oilseed and fodder; (2) winter oilseed; (3) winter fodder; (4) vegetable genotypes. The most extreme allelic variation was observed in a spring kale from the United Kingdom and a Japanese spring vegetable genotype, and two winter rape accessions from Korea and Japan, respectively. Unexpectedly the next most distinct genotypes were two old winter oilseed varieties from Germany and Ukraine, respectively. A number of other accessions were also found to be genetically distinct from the other material of the same type. The molecular genetic information gained enables the identification of untapped genetic variability for rapeseed breeding and is potentially interesting with respect to increasing heterosis in oilseed rape hybrids.     

Time of seed collection and germination in rocket, Erucavesicaria (L.) Cav. (Brassicaceae)

The increasing importance of rocket Erucaspp. as a leaf and oil crop, and especially as a Fourth Generationvegetable, calls for a better understanding of several basic aspectsof its biology. Knowledge on seed germination behaviour is necessaryto optimize the management of the plant in the field and inseedbanks. Seed germination of several samples of rocket was assayedin the laboratory under different incubation conditions. Germinationin the two studied populations was fairly high, ranging from68% to 96%. However, remarkable variation was foundwithin one of them according to the date of collection of the sample,ranging from 78–96% for those collected in summer(LG1 and LG2) to 21–29% for that collected inautumn (LG3). Neither time of storage nor GA₃treatments had any significant effect on this low percentage, whichcould only be significantly improved with scarification, up to47% by dry heat and up to 66% by immersion in liquidnitrogen. Dormancy and low seed viability probably originating fromeffects of environmental factors during seed formation and maturationseem to play a role in the low germination percentage of sampleLG3.     

Genetic diversity of the African hexaploid species Solanum scabrum Mill. and Solanum nigrum L. (Solanaceae)

Two hexaploid species of Solanum sect. Solanum are present in Africa: Solanum scabrum and S. nigrum. Solanum scabrum is a widely cultivated species and is used as a leafy vegetable, as a source of medicine and as a source of ink dye. In previous studies a wide range of morphological diversity has been reported in this species and in some studies subspecies have been proposed. Subspecies are also recognized in S. nigrum. However, it has not been established whether or not the morphological differences are reflected at the genomic level. The present study applies AFLPs to study the genetic diversity in S. scabrum and its relationship to geographical provenance, morphological differences and the possible existence of subspecies within S. scabrum and S. nigrum. The data obtained were analyzed with cluster analysis (using UPGMA and NJ). The results indicate that the genetic variation within S. scabrum was higher within accessions than between accessions. Accessions did not cluster according to their geographical provenance, indicating that accessions from different geographical areas were not significantly different genetically. The clustering reflected neither morphological differences nor domestication status (cultivated or wild). The morphological differences exhibited by S. scabrum could be due to selection by farmers for different plant types. The AFLP derived clustering pattern did not segregate the subspecies recognized in S. scabrum and S. nigrum into separate subclusters.     

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.     

Plantations of Convallaria majalis L. as a threat to the natural stands of the species: Genetic variability of the cultivated plants and natural populations

The level of polymorphism, genetic variability and relatedness of Convallaria majalis-populations (species native in Poland, under partial legal protection) obtained from three Polish regions and from commercial producers (Polish and Dutch) were studied. In addition the differences between the cultivated plants and those occurring in natural stands were analyzed. Each region was represented by at least 20 populations among which half were collected in natural stands and half from cultivation sites (botanical gardens, private gardens and cemeteries), and compared with samples obtained directly from commercial producers. Seven primer pairs used for AFLP profiling amplified 466 scoreable DNA fragments that were used for multidimensional scaling and clustering. The above analyses make it possible to clearly distinguish among individuals and revealed groups of populations according to their geographic origin. Samples from populations collected in natural stands and cultivated in the same region did not differ from each other significantly.These results suggested that cultivated plants were probably obtained directly from the natural stand and the influence of plant cultures on natural populations was rather small.     

Genetic diversity, conservation, and utilization of Theobroma cacao L.: genetic resources in the Dominican Republic

Cacao (Theobroma cacao L.) is a significant agricultural commodity in the Dominican Republic, which ranks 11th in the world for cacao exports. To estimate genetic diversity, determine genetic identity, and identify any labeling errors, 14 SSR markers were employed to fingerprint 955 trees among cacao germplasm accessions and local farmer selections (LFS). Comparisons of homonymous plants across plots revealed a significant misidentification rate estimated to be 40.9 % for germplasm accessions and 17.4 % for LFS. The 14 SSRs amplified a total of 117 alleles with a mean allelic richness of 8.36 alleles per locus and average polymorphism information content (PIC) value of 0.67 for the germplasm collection. Similar levels of variation were detected among the LFS where a total of 113 alleles were amplified with a mean of 8.07 alleles per locus and PIC of 0.57. The observed heterozygosity (H_obs) was 0.67 for the germplasm collection and 0.60 for LFS. Based on population structure analysis 43.9 % of the germplasm accessions and 72.1 % of the LFS are predominantly of the Amelonado ancestry. Among these Amelonado, 51.7 % for the germplasm collection and 50.6 % for LFS corresponded to Trinitario hybrid lineage. Criollo ancestry was found in 7.6 and 9.5 % of the germplasm accessions and LFS, respectively. The Contamana, Nacional, and Iquitos backgrounds were also observed in both populations, but the Curaray background was only detected in the germplasm accessions. No Purús or Guiana ancestry was found in either of the populations. Overall, significant genetic diversity, which could be exploited in the Dominican Republic breeding and selection programs, was identified among the germplasm accessions and LFS.     

From genetic diversity and structure to conservation: Genetic signature of recent population declines in three mouse lemur species (Microcebus spp.)

The exceptional biodiversity of Madagascar is threatened by anthropogenic landscape changes that took place during the 2000 years of human colonization. This study focuses on the influence of geographic distance and forest fragmentation on genetic diversity and population differentiation of three rare, nocturnal, arboreal lemur species in northwestern Madagascar. Historic declines in population sizes as a consequence of forest fragmentation are quantified and dated. Eighteen sites were visited, and a total of 205 Microcebus ravelobensis, 45 M. bongolavensis and 78 M. danfossi were genotyped with eight microsatellite loci. Genetic differentiation among the sites, as measured by F_ST, ranged from 0.01 to 0.19. These values were significant in almost all cases and indicated genetic structure in the samples. Isolation-by-distance was detected in one species and a STRUCTURE analysis indicated that fragmentation further promoted genetic differentiation. Bayesian methods revealed that populations from all three species underwent a major demographic collapse of around two orders of magnitude. This decrease probably began after the arrival of humans, most likely within the last 500 years. This result suggests that anthropogenic changes may have been limited during the first 1500 years of human colonization in all three ranges. Two of the study species (M. danfossi, M. bongolavensis) lack effectively protected areas in their ranges. Consequently, quick conservation actions are now needed in order to secure the remaining genetic diversity of these species.     

水稻籽粒碳氮代谢与品质性状间遗传相关性的研究

研究分析水稻籽粒C、N代谢与稻米主要品质性状间遗传相关性结果表明,水稻籽粒C、N代谢与稻米主要品质性状间有一定遗传相关性,提高可溶性糖含量,则糖氮比显著提高,糙米长、千粒重和直链淀粉含量显著降低;提高全N含量可能显著提高糙米厚和直链淀粉含量,而糖氮比、糙米长和千粒重随之显著降低;随糖氮比的提高,糙米厚、千粒重和直链淀粉含量将显著降低。种子、细胞质和母体植株3套遗传体系同时对成对性状的遗传相关性起作用,且各遗传体系在不同成对性状间的作用效果各异,可溶性糖含量与糙米宽、可溶性糖含量与糙米厚、全N含量与糙米长、全N含量与糙米厚等成对性状间遗传相关性主要受种子直接效应的控制;而可溶性糖含量与糙米长宽比、可溶性糖含量与千粒重、可溶性糖含量与直链淀粉含量、全N含量与糙米宽、全N含量与糙米长宽比、糖氮比与糙米宽、糖氮比与糙米厚等成对性状则以母体植株效应为主。     

Microbial diversity in soil: ecological theories, the contribution of molecular techniques and the impact of transgenic plants and transgenic microorganisms

This review mainly discusses three related topics: the application of ecological theories to soil, the measurement of microbial diversity by molecular techniques and the impact of transgenic plants and microorganisms on genetic diversity of soil. These topics were debated at the Meeting on Soil Emergency held in Erice (Trapani, Italy) in 2001 for the celebration of the 50th anniversary of the Italian Society of Soil Science. Ecological theories have been developed by studying aboveground ecosystems but have neglected the belowground systems, despite the importance of the latter to the global nutrient cycling and to the presence of life on the Earth. Microbial diversity within the soil is crucial to many functions but it has been difficult in the past to determine the major components. Traditional methods of analysis are useful but with the use of molecular methods it is now possible to detect both culturable and unculturable microbial species. Despite these advances, the link between microbial diversity and soil functions is still a major challenge. Generally studies on genetically modified bacteria have not addressed directly the issue of microbial diversity, being mainly focused on their persistence in the environment, colonization ability in the rhizosphere, and survival. Concerns have been raised that transgenic plants might affect microbial communities in addition to environmental factors related to agricultural practice, season, field site and year. Transgenic plant DNA originating from senescent or degraded plant material or pollen has been shown to persist in soil. Horizontal transfer of transgenic plant DNA to bacteria has been shown by the restoration of deleted antibiotic resistance genes under laboratory in filter transformations, in sterile soil or in planta. However, the transformation frequencies under field conditions are supposed to be very low. It is important to underline that the public debate about antibiotic resistant genes in transgenic plants should not divert the attention from the real causes of bacterial resistance to antibiotics, such as the continued abuse and overuse of antibiotics prescribed by physicians and in animal husbandry.     

Genetic diversity in the Olive tree (Olea europaea L. subsp. europaea) cultivated in Portugal revealed by RAPD and ISSR markers

To assess the genetic diversity of the most important olive cultivars used in Portugal, a base collection was established with two hundred and one accessions of eleven cultivars from the different agro-ecological-regions (AER) of olive oil production. Inter-cultivar diversity was evaluated using seven RAPD primers producing fifty-nine polymorphic markers that enable cultivar distinction. Discriminant analysis according to fruit use and AER revealed a genetic structure associated with local selection both for fruit exploitation and agro-ecological adaptation. Intra-cultivar diversity of the ancient cultivar Galega was also investigated. Three RAPD and five ISSR primers produced ninety-three polymorphic markers upon seventy-seven accessions from five AERs. Total accession discrimination was achieved. UPGMA clustering and discriminant analysis revealed that the genetic diversity was predominantly structured according to accessions origin. The within and among AER variation revealed by AMOVA supported this genetic structure and showed a high proportion of intra-AER variability. These evidences suggest that Galega is composed by a mixture of different genotypes adapted to local conditions, indicating that this cultivar is in an early stage of domestication and should be treated as a landrace instead of a uniform cultivar. The assessment of Galega genetic diversity within each of the five AERs indicated the highest significant level (H_g = 6.23 at p< 0.001) in Ribatejo-Santarém. This finding associated with the distinctiveness of Galega in relation to other Portuguese cultivars and with the recent insights of olive tree domestication allowed us to hypothesize that Ribatejo-Santarém was the ecological region of origin and dispersion of this ancient cultivar.     

连作对再植枸杞根际细菌群落多样性和群落结构的影响研究

受枸杞道地产区土地资源等因素限制,连作障碍已成为影响枸杞产业发展的重要原因之一,导致严重的经济损失.研究连作条件下枸杞农田土壤生态系统微生物群落的演替规律对枸杞产业的可持续发展具有重要的理论意义.以宁夏银川市南梁农场连作多年的枸杞地为研究对象,利用Illumina MiSeq测序技术分析了连作对再植枸杞根际/非根际细菌群落的影响.结果表明,连作地显著抑制再植枸杞苗地径的增加,且其土壤pH较对照样地显著降低(p<0.05).测序结果证实,与对照样地相比,连作地再植枸杞根际土壤细菌物种数显著降低(p<0.05),细菌群落α多样性下降(p>0.05).主坐标分析表明,连作和对照样地间枸杞非根际细菌群落结构无明显差异,但连作显著改变再植枸杞根际细菌的群落结构.对细菌群落丰度的统计分析发现,连作地枸杞根际浮霉菌门、非根际假单胞菌门的相对丰度较对照样地显著降低(p<0.05).此外,冗余分析结果表明:枸杞园土壤pH和有效磷含量是影响枸杞非根际土壤细菌群落结构变化的主要因素,分别解释了41.8%和35.4%的群落结构变化(p<0.05),其他土壤因子无统计学意义,但土壤理化因子对再植枸杞根际细菌群落结构变化的影响均未达显著水平.这些结果证实连作能够显著抑制再植枸杞生长、影响再植枸杞根际细菌群落结构和多样性,干扰枸杞与土壤细菌群落间的互作关系.这些研究结果将为解析枸杞连作障碍机制提供理论基础.     

荫蔽栽培与亏缺灌溉对干热区小粒咖啡生长和冠层结构的影响

干热区小粒咖啡水、光管理粗放,高效生产受到限制。通过大田试验,采用完全组合设计,设3个灌水水平[充分灌水(FI)、轻度亏缺灌水(DIL)和重度亏缺灌水(DIS)]和4个荫蔽栽培模式[无荫蔽(S0):单作咖啡;轻度荫蔽(SL):4行咖啡间作1行香蕉;中度荫蔽(SM):3行咖啡间作1行香蕉;重度荫蔽(SS):2行咖啡间作1行香蕉],研究香蕉荫蔽栽培下亏缺灌溉对干热区小粒咖啡生长和冠层结构的影响。结果表明:与FI相比,其余灌水处理的株高增量和新梢长度分别减少13.62%～23.94%和8.82%～13.96%,总定点因子增加9.55%～34.97%。与S0相比,其余荫蔽处理的株高增量、茎粗增量、冠幅增量、新梢长度和叶面积指数分别增加18.33%～33.65%、6.43%～15.47%、5.38%～12.60%、8.82%～24.69%和5.18%～22.85%,冠层开度、林隙分数、平均叶倾角、总定点因子和透光率分别减少4.42%～15.50%、4.85%～16.49%、5.50%～15.07%、13.78%～41.44%和10.36%～31.78%。相关分析表明,冠层开度、林隙分数、平均叶倾角、直接定点因子、间接定点因子、总定点因子、冠下直接辐射、冠下间接辐射、透光率和消光系数相互之间均呈显著正相关,且分别与冠层叶面积指数呈显著负相关。聚类分析表明,当类间距离为5时,可将12个处理分为3类, FISS、DILSS和FISM处理为第1类, FISL、DILSL、DILSM、DISSS、FIS0和DISSM处理为第2类, DILS0、DISSL和DISS0处理为第3类。其中第1类的生长状况最佳,可作为干热区小粒咖啡灌水处理和香蕉荫蔽栽培模式的优选组合。该结果可为干热区小粒咖啡水光管理提供理论指导。     

Microsatellite variability within and among local landrace populations of tea, Camellia sinensis (L.) O. Kuntze, in Kyoto, Japan

Genetic variability within and among eight landrace populations of tea (Camellia sinensis (L.) O. Kuntze) located in southern Kyoto, Japan, was surveyed with six microsatellite markers. The average number of alleles per locus was 3.83 to 4.67 for landrace populations, whereas the corresponding value among modern cultivars and breeding lines was 6.63. Expected heterozygosity values averaged over loci within landrace populations ranged from 0.498 to 0.723. A similar level of variation, 0.682, was observed for cultivars and breeding lines. High fixation index values (0.177–0.417) for each population are consistent with biparental inbreeding within the population. Genetic differentiation among local populations was extremely low with F _ST = 0.062, although AMOVA revealed significant differentiation among landrace populations. We propose that these populations share a common ancestral gene pool and that some degree of artificial selection within each population has been performed by local farmers. Neighbor-joining analysis revealed that genetic relationships among populations reflect geographical location of populations. This might result from more frequent genetic exchange by nearby farmers.     

Decline of an isolated timber rattlesnake (Crotalus horridus) population: Interactions between climate change, disease, and loss of genetic diversity

Extinction of populations from anthropogenic forces rarely has a single cause. Instead, population declines result from a variety of factors, including habitat loss, inbreeding depression, disease, and climate change. These impacts often have synergistic effects that can lead to rapid decline in isolated populations, but case studies documenting such processes are rare. Here, we describe the recent decline of the last known population of timber rattlesnakes (Crotalus horridus) in the state of New Hampshire. We used polymorphic nuclear DNA markers to compare genetic diversity of this population to other populations in the region that are not isolated. We also compare results from ongoing field monitoring of these populations. Genetic analyses reveal that the New Hampshire population lacks genetic diversity and exhibits signs of a recent bottleneck. New Hampshire snakes also exhibited high levels of morphological abnormalities (unique piebald coloration, amelanistic tongues) indicative of inbreeding depression. Furthermore, after a year with exceptionally high summer rainfall, a skin infection of unknown etiology caused significant mortality in the New Hampshire population, whereas other surveyed non-inbred populations were unaffected. This case study demonstrates how different anthropogenic impacts on natural environments can interact in unexpected ways to drive threatened populations toward extinction.     

Genetic diversity and differentiation of <Emphasis Type="Italic">Camellia sinensis</Emphasis> L. (cultivated tea) and its wild relatives in Yunnan province of China,revealed by morphology,biochemistry and allozyme studies

We evaluated morphological, isozyme and biochemical diversity of a total of 87 accessions in the genus Camellia [Camellia sinensis var. sinensis (10), C. talinensis (7), C. sinensis var. dehungensis (3), C. crassicolumna (3) and C. sinensis var. assamica (64)]. Great variation of morphological characters was apparent within each taxa. Across the five taxa, all leaf and most flower quantitative characters showed significant differences while all fruit quantitative characters measured did not differ significantly, and, seven (i.e., life form, bud color, petal texture, pubescence on ovary, style number, stamen location and locule per fruit) of the 33 qualitative characters yield significant differences. As a whole, caffeine content had the highest variation with CV of 22.7%, water extract solid showed the least variation (13.4%) and content of polyphenols (20.0%) and free amino acids (18.8%) showed intermediate variations. Camellia taliensis and C. sinensis var. assamica had significantly higher content of polyphenols and water extract solid than in the other three taxa, while no significant differences were detected for the content of caffeine and free amino acids. For allozyme study, 14 loci presented good resolution, among which, nine loci (64%) were polymorphic in each taxon (AAT-3, FUM-1, 6PDG-1, G6PDH-1, G3PDH-1, ME-1, PGM-1, PGM-2 and SKD-1). The percentage of polymorphic loci (P) for each taxon was 21.4–50.0%. Mean heterozygosity per locus (H _e ) varied 0.114–0.218. F _ST value indicated that only 4.6% of the variations could be ascribable to genetic differences among taxa. Genetic relationships among the five taxa revealed by allozymes, were also exposed by the result of clustering of the morphological and biochemical characters.     

Genetic diversity in cucumber (Cucumis sativus L.): I. A reevaluation of the U.S. germplasm collection

Genetic variation within the U.S. cucumber collection (Cucumis sativus var. sativus L. and var. hardwickii (Royle) Alef.) was assessed by examing the variation at 21 polymorphic isozyme loci and comparing the results of this investigation with a similar previous analysis of 14 loci. About 29% (15 of 51) of the enzyme systems examined in an initial survey were polymorphic. Seven loci (Ak-2, Ak-3, Fdp-1, Fdp-2, Mpi-1, Pep-gl and Skdh) which were not previously used to estimate genetic diversity, were assessed. On average, 1.4 loci were polymorphic per enzyme system and 2.2 alleles were present per polymorphic locus. The frequency of polymorphisms was relatively low for Fdp-1(2) (0.01), Mpi-1(1) (0.03), and Skdh(1) (0.02). Principal component and cluster analyses of allelic variation at polymorphic loci separated a diverse array of 757 cucumber accessions from the U.S. National Plant Germplasm Systesm's (NPGS) collection into distinct groups by country (45 nations examined). All accessions of C. s. var. sativus were isozymically distinct from C. s. var. hardwickii, which were themselves dissimilar from each other. Data suggest that C. s. var. hardwickii is not a feral derivative of extant C. s. var. sativus populations. The allelic profile of C. s. var. sativus accessions originating from Burma, Thailand, Indonesia, Hong Kong, Zimbabwe and Ethiopia were distinct from the other accessions examined. Allelic fixation has occurred at Pgd-2 in accessions from Burma, and at Ak-2 in accessions from Zimbabwe and Ethiopia. Some of the countries examined that were in close geographic proximity (e.g., Thailand, Indonesia and Hong Kong) contained accessions with similar isozyme profiles. Accessions are fixed for certain alleles [e.g., Gr(1) (100%), Fdp-1(1) (100%) and Mpi-2(2) (50%) for accessions from Thailand, Indonesia and Hong Kong]. Grouping countries by continent or sub-continent (i.e., North and South American, China, Eastern Europe, Western Europe) and by numbers of accessions examined (i.e., India/Burma, Iran, Japan, Turkey, and remaining accessions) was used to identify accessions with unique allozymic profiles [PIs 209064 (USA), 257486 (China), 188749 (Egypt), 285607 (Poland), 369717 (Yugoslavia), 357844 (Poland), 255936 (Netherlands), 183127 (India), 200818 (Burma), 200815 (Burma), 137836 (Iran), 227013 (Iran), 227235 (Iran), 451976 (Japan), 181752 (Syria), 181874 (Syria), 169383 (Turkey), 171613 (Turkey)].     

AFLP fingerprinting of Anchusa (Boraginaceae) in the Corso-Sardinian system: Genetic diversity, population differentiation and conservation priorities in an insular endemic group threatened with extinction

Although several plants endemic to Corsica and Sardinia are included in various redlists, no attempts have been made to analyse their genetic diversity with molecular techniques. Genus Anchusa occurs with seven taxa in either mountain or coastal habitats of the two islands, but the very restricted range and low population size pose these endemisms in a very precarious conservation status. Highly variable markers (AFLP) were therefore used to analyse the patterns and levels of genetic diversity in a sample of 11 populations from the entire range of the group.Results indicate the separation between a mountain genic pool including Anchusa formosa, Anchusa capellii and Anchusa montelinasana, and four groups of coastal accessions. In spite of small size, mountain taxa show low interpopulation differentiation (F_st = 0.02) and relatively high intrapopulation genetic variation (0.365), while coastal accessions showed on average a stronger differentiation (mean F_st = 0.20) and a lower diversity (0.281), possibly due to higher rates of inbreeding. The particularly low levels of variation found in A. sardoa, A. littorea and A. crispa ssp. maritima from the Coghinas bay are likely due to a historical decrease of populations and to bottleneck events caused by loss of habitat and natural stochastic factors on sand dune ecosystems. While habitat maintenance and regulation of grazing by domestic herbivores should be sufficient to ensure the persistence of the mountain endemics, additional actions of in situ and ex situ conservation are needed for the critically endangered coastal species A. sardoa and A. littorea. A. crispa showed a relatively high variation, especially on Corsica. No correlation between population size and genetic variation was found in the latter species, highlighting the importance of the small patches for its conservation. Also, the genetic separation between subspecies crispa and maritima stresses the need of keeping them distinct in redlists and conservation actions on Sardinia.