Papers

Authors: Bissessur, P., et al.

Publication Year: 2019

Authors: Allen, E., et al.

Publication Year: 2019

Authors: Magos Brehm, J., et al.

Publication Year: 2019

Authors: Holness, S., et al.

Publication Year: 2019

Authors: Wainwright, W., et al.

Publication Year: 2018

Authors: Sharma, T.V.R.S., et al.

Publication Year: 2018

Authors: Al-Hajaj, N., et al.

Publication Year: 2018

Authors: Rubio Teso, M.L., et. al.

Publication Year: 2018

Authors: Labokas, J., et al.

Publication Year: 2018

Authors: Norton, S.L., et al.

Publication Year: 2017

Authors: Jin, X., et al.

Publication Year: 2018

Authors: Kumar, S., et al.

Publication Year: 2018

Authors: Talip, M., et al.

Publication Year: 2018

Authors: Dudnikov, A.J.

Publication Year: 2018

Authors: Okoshi, M., et al.

Publication Year: 2018

Authors: Mousavi-Derazmahalleh, M., et al.

Publication Year: 2018

Authors: Zair, W., et al.

Publication Year: 2018

Authors: Kakizaki, A., et al.

Publication Year: 2017

Authors: Kassa, A., et al.

Publication Year: 2017

Authors: van Treuren, R., et al.

Publication Year: 2017

Authors: Kraft, K.H., et al.

Publication Year: 2013

Authors: Volk, G.M., et al.

Publication Year: 2017

Authors: Singh, R.K., et al.

Publication Year: 2017

Authors: Bellon, M.R., et al.

Publication Year: 2017

Authors: Aboukhalid, K., et al.

Publication Year: 2017

Authors: Amer, W.M., et al.

Publication Year: 2013

Authors: Aguirre-Liguori, J.A., et al.

Publication Year: 2017

Authors: Taylor, A., et al.

Publication Year: 2017

Authors: Frese, L., et al.

Publication Year: 2017

Authors: Avni, R., et al.

Publication Year: 2017

Authors: Gorim, L.Y. and Vandenberg, A.

Publication Year: 2017

Authors: Rodríguez-Arévalo, I., et al.

Publication Year: 2017

Authors: Leal-Bertioli, S.C.M., et al.

Publication Year: 2017

Authors: Avni, R., et al.

Publication Year: 2017

Authors: Loskutov, I.G., et al.

Publication Year: 2017

Authors: Ohta, A., et al.

Publication Year: 2017

Authors: Wang, H., et al.

Publication Year: 2017

Authors: Aguirre-Gutiérrez, J., et al.

Publication Year: 2017

Authors: Bethke, P.C., et al.

Publication Year: 2017

Authors: Wang, Y., et al.

Publication Year: 2017

Authors: Morillo, E., et al.

Publication Year: 2017

Authors: Wiersma, T., et al.

Publication Year: 2017

Authors: Lala, S., et al.

Publication Year: 2017

Authors: Thomas, E., et al.

Publication Year: 2017

Authors: Fischer, E., et al.

Publication Year: 2017

Authors: Taylor, N.G., et al.

Publication Year: 2017

Authors: Naredo, M.E.B., et al.

Publication Year: 2017

Authors: Beghe, D., et al.

Publication Year: 2017

Authors: Munoz, N., et al.

Publication Year: 2017

Authors: Chin, J.H., et al.

Publication Year: 2017

Authors: Boucheffa, S., et al.

Publication Year: 2017

Authors: Cadima Fuentes, X., et al.

Publication Year: 2017

Authors: Rakha, M., et al.

Publication Year: 2017

Authors: Celeste, S.M., et al.

Publication Year: 2017

Authors: Loskutov, I.G., et al.

Publication Year: 2017

Authors: Cunniff, J., et al.

Publication Year: 2017

Authors: Chávez-Pesqueira, M., et al.

Publication Year: 2016

Authors: Bamberg, J., et al.

Publication Year: 2016

Authors: Pandey, A., et al.

Publication Year: 2008

Authors: Clark, L.V., et al.

Publication Year: 2016

Corporate Author: Decroocq, S., et al.

Publication Year: 2016

Authors: Aryakia, E., et al.

Publication Year: 2016

Authors: Che, Y., et al.

Publication Year: 2016

Authors: Thormann, I., et al.

Publication Year: 2016

Authors: Barazani, O., et al.

Publication Year: 2008

Authors: Maxted, N., et al.

Publication Year: 2008

Authors: Kosterin, O.E.

Publication Year: 2016

Authors: Thormann, I., et al.

Publication Year: 2016

Authors: Mihoub, I., et al.

Publication Year: 2016

Authors: Jena, K.K., et al.

Publication Year: 2016

Authors: Oliveira, H., et al.

Publication Year: 2016

Authors: Nosenko, T., et al.

Publication Year: 2016

Authors: Silva, N.C.dA., et al.

Publication Year: 2015

Authors: Syfert, M.M., et al.

Publication Year: 2016

Authors: Bertioli, D.J., et al.

Publication Year: 2016

Authors: Bomfim, N. and Nassar, N.M.A.

Publication Year: 2014

Authors: Dossett, M. and Finn, C.E.

Publication Year: 2016

Authors: Zhang, D., et al.

Publication Year: 2016

Authors: Castañeda-Álvarez, N.P., et al.

Publication Year: 2016

Authors: da Silva, M.J., et al.

Publication Year: 2016

Authors: Pan, C., et al.

Publication Year: 2015

Authors: Wilson, W.D., et al.

Publication Year: 2016

Potatoes are grown as a staple food in a number of countries around the world. Potatoes production is fourth at the worldwide level and provides carbohydrates and other nutrients in several developing countries. In South America a large diversity of wild and cultivated potato genotypes have been identified, from which several species have been described in Colombia. The last known collections of wild potato germplasm in Colombia were performed up to 1992, and we know little of wild potato distribution since that time. Several factors may threaten these populations, and we performed field surveys of the Colombian populations, as well as a literature review, studies of herbarium specimens from eight Colombian herbaria and databases from reference collections available on the internet. Based in these data we performed field trips in several Colombian regions where wild and cultivated species were reported previously. We identified Solanum andreanum Baker, S. colombianum Dunal and S. flahaultii Bitter, populations according to the taxonomic concepts of Spooner and Fajardo; or S. andreanum, S. colombianum, S. flahaultii, S. moscopanum Hawkes and S. tuquerrense Hawkes, according to the taxonomy of Hawkes. We observed habitat loss or disturbance that may partially explain the apparent decrease or eventual disappearance of some species at specific sites.

Authors: Velez, J.M., et al.

Publication Year: 2016

Information on plant adaptation can be very useful in agrobiodiversity studies. Ecogeographical land characterization (ELC) maps constitute a new tool in this direction with great potential. To assess the usefulness of this approach, an ELC map of Spain was created through multivariate methods. Its performance to characterize plant habitat preferences was compared with existing ecological regions and land cover maps. Collecting sites and seed weight from eight plant species were used to test the ELC map. Categories from each map were assigned to accessions using collecting sites. Chi-square tests were applied to test if category frequency distributions for each species followed a distribution proportional to the relative frequency of categories in each map. The tests found significant differences in the eight species studied. Thus, Bonferroni confidence intervals (BCI) classified categories from maps in preferred, neutral or avoided habitats. Seed weight was used as a proxy for plant adaptation. Comparison between observed and expected ranking of BCI and quartile classes in terms of seed weight means, and GLM and post-hoc tests carried out to test the effect of these classes upon seed weight showed consistently better results for the ELC map. Species results and applications of ecogeographic maps in plant genetic resources conservation are discussed.

Authors: Parra-Quijano, M. et al.

Publication Year: 2012

An efficient germplasm collecting method was evaluated using six Lupinus species and the Spanish Lupinus collection as a study case. This method includes the application of geographic information systems, ecogeographical land characterization maps, species distribution models and gap analysis to identify prioritized collecting sites. To evaluate the efficiency of this collecting method, field collecting expeditions were carried out focusing on prioritized sites and the results of these collections were analyzed. Prioritized sites were identified using spatial and ecogeographical gaps, and potential species richness maps. The spatial gaps corresponded to populations non-included in the collection but recorded by other information sources while ecogeographical gaps corresponded to spatial gaps that were located in ecogeographical categories (obtained from the ecogeographical map) that were scarcely represented in the collection. A potential Lupinus species richness map was obtained by adding the information of single maps of Lupinus species distribution models. Subsequently, prioritized sites were obtained in ecogeographical gaps with high potential species richness values. Collecting expeditions were made in Spain in 2006, 2007 and 2008. Results showed that using the efficient germplasm collecting methodology was highly positive not only from a quantitative viewpoint (between 7.8 and 11% increase) but also in qualitative terms, focusing collection efforts in ecogeographical categories with low or null representation in the Spanish Lupinus collection (41% of the new accessions). Phenotypic differences related to adaptation to environment were observed in the field between the populations that grow in low or null represented categories and those that grow in highly represented categories.

Authors: Parra-Quijano, M. et al.

Publication Year: 2012

Aim: Gap analysis is a well-established conservation technique that identifies areas in which selected elements of biodiversity are represented and through comparison with existing in situ protected area networks identifies habitats or ecosystems that need additional protection. We aim to demonstrate that gap analysis may be extended to encompass both in situ and ex situ genetic diversity conservation strategies. Location: Global, with exemplar case study from sub-Saharan Africa. Methods: An extended methodology of gap analysis is proposed that involves the following steps: (1) circumscription of target taxon and target area; (2) assessment of natural diversity through a review of intrinsic taxonomic, genetic and ecogeographical diversity combined with threat assessment; (3) assessment of current complementary in situ and ex situ conservation strategies; and (4) reformulation of the conservation strategy through analysis of the differences between the pattern of natural, intrinsic diversity and the elements of that diversity already effectively represented by existing in situ and ex situ conservation actions. Results: To illustrate the gap analysis approach proposed, the methodology was applied to the conservation of African Vigna species (cowpea Vigna unguiculata (L.) Walp. and its wild relatives) and indicated: (1) genetic reserves should be established at the southern tip of Lake Tanganyika, the coastal area of Sierra Leone and between Lake Victoria and the other Great Lakes, and (2) 14 taxa and several countries should be targeted for further seed collection. Main conclusions: The robust nature of the extended methodology for gap analysis has been demonstrated and indicates that its scope as an effective conservation tool may be expanded to fully address the need for a more comprehensive and complementary conservation strategy that encompasses both in situ and ex situ applications. However, it should be stressed that the methodology is applicable for any form of biodiversity (wild or cultivated), where the conservation of genetic diversity is the prime goal.

Authors: Maxted, N. et al.

Publication Year: 2008

Crop wild relatives (CWR) play a key role in providing genetic diversity for crop adaptation and improvement and their in situ conservation is the most appropriate action to safeguard them, as it allows new diversity to be generated. Knowledge about contemporary evolutionary processes, adaptive responses to climate change, and trends in genetic diversity status should support the identification of target populations for in situ management and monitoring actions. Generating this knowledge requires monitoring and assessing diversity at various time points. Analyses of past trends have been particularly limited for CWR due to patchy, scarce availability of historical data and seed material, which would constitute a historical baseline for comparison with contemporary populations. Past germplasm collecting missions and their associated documentation can contribute to filling this gap. We analysed as a potential resource the Bioversity Collecting Database, which includes sample-level records for over 200,000 landrace and CWR samples mainly collected between 1975 and 1995. 27% of the samples collected are wild species, of which 73% are georeferenced. The database links original sample passport data with collecting reports and with accession numbers from the genebanks conserving the collected material, which allows the seeds collected to be tracked. This data resource was used to implement a study on temporal variation in wild barley. Wild barley (Hordeum vulgare subsp. spontaneum), originally collected in 1981 and stored in genebanks, was re-collected from historical sites in Jordan. Most original accessions from the 1981 mission were traced in genebanks and phenotypic and molecular marker data compared between the 1981 and 2012 collections.

Authors: Thormann, I. and Dulloo, M.E.

Publication Year: 2015

ABSTRACT: Habitat fragmentation is a leading threat to biodiversity, with extinction rates increasing as anthropogenic alteration of the environment increases. Crop to wild hybridisation is a threat to biodiversity resulting from native vegetation being replaced with agriculture and crops. Remnant populations of Australia's vulnerable subtropical rainforest tree Macadamia tetraphylla are potentially threatened by hybridisation with M. integrifolia orchard crops. Leaf samples were taken from ten crop-wild population sites across the distribution of M. tetraphylla in New South Wales, Australia. Microsatellite markers were used to investigate the presence of marker alleles from cultivars in wild populations, and genetic diversity within and among wild M. tetraphylla populations. Despite the small size of the wild M. tetraphylla populations, relatively high genetic diversity and low inbreeding were observed. This study found that M. integrifolia orchard trees pollinated wild M. tetraphylla trees, and that orchard seeds dispersed into wild populations, providing the first evidence of crop-wild gene flow in macadamia. Pollen flow between relatively close wild populations maintains genetic diversity, reduces inbreeding, and also enables gene flow from nearby M. integrifolia orchards. The potential for crop to wild gene flow and hybridisation risks the integrity and persistence of wild populations.

Authors: O'Conner, K. et al.

Publication Year: 2015

Crop wild relatives (CWR) are a rich source of genetic diversity for crop improvement. Combining ecogeographic and phylogenetic techniques can inform both conservation and breeding. Geographic occurrence, bioclimatic, and biophysical data were used to predict species distributions, range overlap and niche occupancy in 36 taxa closely related to sunflower (Helianthus annuus L.). Taxa lacking comprehensive ex situ conservation were identified. The predicted distributions for 36 Helianthus taxa identified substantial range overlap, range asymmetry and niche conservatism. Specific taxa (e.g., Helianthus deblis Nutt., Helianthus anomalus Blake, and Helianthus divaricatus L.) were identified as targets for traits of interest, particularly for abiotic stress tolerance, and adaptation to extreme soil properties. The combination of techniques demonstrates the potential for publicly available ecogeographic and phylogenetic data to facilitate the identification of possible sources of abiotic stress traits for plant breeding programs. Much of the primary genepool (wild H. annuus) occurs in extreme environments indicating that introgression of targeted traits may be relatively straightforward. Sister taxa in Helianthus have greater range overlap than more distantly related taxa within the genus. This adds to a growing body of literature suggesting that in plants (unlike some animal groups), geographic isolation may not be necessary for speciation.

Authors: Kantar, M. et al.

Publication Year: 2015

In light of the growing concern over the potentially devastating impacts on biodiversity and food security of climate change and the massively growing world population, taking action to conserve crop wild relatives (CWR), is no longer an option — it is a priority. Crop wild relatives are species closely related to crops, including their progenitors, many of which have the potential to contribute beneficial traits to crops, such as pest or disease resistance, yield improvement or stability. They are a critical component of plant genetic resources for food and agriculture (PGRFA), have already made major contributions to crop production and are vital for future food security; their systematic conservation in ways that ensure their continuing availability for use is therefore imperative. This is a complex, interdisciplinary, global issue that has been addressed by various national and international initiatives. Drawing on the lessons learnt from these initiatives we can now propose a global approach to CWR conservation, the key elements of which are: (1) estimating global CWR numbers, (2) assessment of the global importance of CWR diversity, (3) current conservation status, (4) threats to CWR diversity, (5) systematic approaches to CWR conservation, (6) CWR informatics, and (7) enhancing the use of CWR diversity.

Authors: Maxted, N. et al.

Publication Year: 2010

Authors: Vincent, H., et al.

Publication Year: 2013

ABSTRACT: The main objective of the“Adapting Agriculture to Climate Change” project is to collect and protect the genetic diversity of a portfolio of plants with the characteristics required for adapting the world's most important food crops to climate change. The initiative also aims to make available this diversity in a form that plant breeders can readily use to produce varieties adapted to the new climatic conditions that farmers, particularly in the developing world, are already encountering. Such adaptation is a key component of securing the world's future food production. This paper serves to inform interested researchers of this important initiative and encourage collaboration under its umbrella.

Authors: Dempewolf, H. et al.

Publication Year: 2014

Authors: Dudnikov, A.J. and Kawahara, T.

Publication Year: 2006

ABSTRACT: The use of crop wild relatives (CWRs) in breeding is likely to continue to intensify as utilization techniques improve and crop adaptation to climate change becomes more pressing. Significant gaps remain in the conservation of these genetic resources. As a first step toward a national strategy for the conservation of CWRs, we present an inventory of taxa occurring in the United States, with suggested prioritization of species based on potential value in crop improvement. We listed 4600 taxa from 985 genera and 194 plant families, including CWRs of potential value via breeding as well as wild species of direct use for food, forage, medicine, herb, ornamental, and/or environmental restoration purposes. United States CWRs are related to a broad range of important food, forage and feed, medicinal, ornamental, and industrial crops. Some potentially valuable species are threatened in the wild, including relatives of sunflower (Helianthus annuus L.), walnut (Juglans regia L.), pepo squash (Cucurbita pepo L.), wild rice (Zizania L.), raspberry (Rubus idaeus L.), and plum (Prunus salicinaLindl.), and few accessions of such taxa are currently conserved ex situ. We prioritize 821 taxa from 69 genera primarily related to major food crops, particularly the approximately 285 native taxa from 30 genera that are most closely related to such crops. Both the urgent collection for ex situ conservation and the management of such taxa in protected areas are warranted, necessitating partnerships between concerned organizations, aligned with regional and global initiatives to conserve and provide access to CWR diversity.

Authors: Khoury, K. et al.

Publication Year: 2013

Authors: Gao, L., et al.

Publication Year: 2002

ABSTRACT: IN THE early 1970s Asia’s rice farmers faced ruin. The brown planthopper, an insect up till then found mostly in Japan, began to appear across the region. It fed on young plants and transmitted grassy stunt virus, causing crops to shrivel and brown. As it swept through Asia’s paddy fields, yields crashed. By the end of the decade it had caused damage costing over $300m—more than $1 billion in today’s money.

Publication Year: 2015

ABSTRACT: This Statement summarizes the results of the third in a series of consultations between agricultural scientists (in particular those interested in the conservation and use of crop diversity in plant improvement) and climate scientists on how to adapt agriculture to climate change. The first meeting, also held at Bellagio (3-7 September 2007), looked at the Conservation and Use of Global Crop Genetic Resources in the Face of Climate Change. It identified three major challenges facing the adaptation process: collecting crop diversity before it disappears, using it to breed better adapted crops, and informing key players of the increased need for the conservation and effective use of crop genetic resources in the face of climate change.

Authors: Guarino, L. et al.

Publication Year: 2010

Authors: Jarvis, A., et al.

Publication Year: 2003

ABSTRACT: Declining rural security and pressures to reduce public-sector expenditures in the late 1990s spurred efforts to develop alternative funding models for Uganda's Kibale National Park (KNP). The Wild Coffee Project, established in 1999 with support from the U.S. Agency for International Development, the World Bank, and the Ford Foundation, sought to develop a market for wild coffee that had been harvested traditionally from areas within today's KNP. The Kibale Forest Foundation, a U.S.-based nonprofit organization, was created to legalize harvests, obtain third-party wild and organic certification, and coordinate management between KNP, the coffee industry, and local communities. Although the project was successful in legalizing, harvesting, and processing the world's first certified wild and organic coffee, efforts to gain entry into the international marketplace failed. Chief among the lessons learned from this project is that for many wild-grown products, the value of “the story”—in both human and conservation terms—is likely to far exceed actual product values. This value differential should be captured through high-value niche markets to avoid low commodity pricing and subsequent pressures to improve financial returns through over harvesting. In addition, local producers should hold significant assets in whatever brands are developed, creating a shared-equity approach that serves social responsibility goals, fosters project sustainability, and ensures a steady stream of positive stories for use in marketing to build brand value. Shared equity—in this case ownership interest in the intellectual property embodied in the brand—provides a second incentive beyond transactional profits that can only be realized if resource conservation is maintained.

Authors: Lilieholm, R. and Weatherly, P.

Publication Year: 2009

Authors: Sun, C.Q., et al.

Publication Year: 2001

ABSTRACT: Conservation of crop wild relatives (CWRs) is a complex interdisciplinary process that is being addressed by various national and international initiatives, including two Global Environment Facility projects (‘In situ Conservation of Crop Wild Relatives through Enhanced Information Management and Field Application’ and ‘Design, Testing and Evaluation of Best Practices for in situ Conservation of Economically Important Wild Species’), the European Community-funded project ‘European Crop Wild Relative Diversity Assessment and Conservation Forum (PGR Forum)’ and the European ‘In situ and On Farm Network’. The key issues that have arisen are: (1) the definition of what constitutes a CWR, (2) the need for national and regional information systems and a global system, (3) development and application of priority-determining mechanisms, (4) the incorporation of the conservation of CWRs into existing national, regional and international PGR programmes, (5) assessment of the effectiveness of conservation actions, (6) awareness of the importance of CWRs in agricultural development at local, national and international levels both for the scientific and lay communities and (7) policy development and legal framework. The above issues are illustrated by work on the conservation of a group of legumes known as grasspea chicklings, vetchlings, and horticultural ornamental peas (Lathyrus spp.) in their European and Mediterranean centre of diversity.

Authors: Heywood, V. et al.

Publication Year: 2007

ABSTRACT: Conservation priorities for Prunus africana, a tree species found across Afromontane regions, which is of great commercial interest internationally and of local value for rural communities, were defined with the aid of spatial analyses applied to a set of georeferenced molecular marker data (chloroplast and nuclear microsatellites) from 32 populations in 9 African countries. Two approaches for the selection of priority populations for conservation were used, differing in the way they optimize representation of intra-specific diversity of P. africana across a minimum number of populations. The first method (S1) was aimed at maximizing genetic diversity of the conservation units and their distinctiveness with regard to climatic conditions, the second method (S2) at optimizing representativeness of the genetic diversity found throughout the species’ range. Populations in East African countries (especially Kenya and Tanzania) were found to be of great conservation value, as suggested by previous findings. These populations are complemented by those in Madagascar and Cameroon. The combination of the two methods for prioritization led to the identification of a set of 6 priority populations. The potential distribution of P. africana was then modeled based on a dataset of 1,500 georeferenced observations. This enabled an assessment of whether the priority populations identified are exposed to threats from agricultural expansion and climate change, and whether they are located within the boundaries of protected areas. The range of the species has been affected by past climate change and the modeled distribution of P. africana indicates that the species is likely to be negatively affected in future, with an expected decrease in distribution by 2050. Based on these insights, further research at the regional and national scale is recommended, in order to strengthen P. africana conservation efforts.

Authors: Vinceti, B. et al.

Publication Year: 2003

ABSTRACT: The Gossypium hirsutum gene pool from Mexico is one of the primary sources for improvement of most of the Acala and Upland cotton growing in the world today. Mexico is also the center of diversity of the Gossypium genus with 11 of the 13 known diploid Gossypium species of the Western Hemisphere endemic to its boundaries. In 2002 and 2003, the current status of these important genetic resources was surveyed, and germplasm was collected in the western states of Mexico. Information was collected to verify current status and circumscription of the endemic Gossypium species. Sixty years after the first in-depth studies of Gossypium in Mexico, increasing human population, modernization and urbanization have severely reduced the survival of G. hirsutum landraces. Representatives of cotton landraces evidently survive only as curiosities in garden plots or dooryards, or as occasional feral plants. Populations of seven known species, G. aridum, G. barbadense, G. gossypioides, G. hirsutum, G. laxum, G. lobatum, and G. schwendimanii, and one undescribed wild diploid Gossypium taxon were located during the survey. In situ conservation of some of these species is threatened. Samples of the collected germplasm were deposited in the Cotton Collection of the US National Plant Germplasm System where they will be available to scientists worldwide for research, breeding, and education. Additionally, a Gossypium species nursery is being established by the Mexican government for the preservation, and as a working legacy, of this resource. Knowledge of the diversity and, consequently, utilization of the genetic resources in these species cannot be fully realized in situ under current conditions.

Authors: Ulloa, M. et al.

Publication Year: 2006

ABSTRACT: Vitis vinifera L. ssp. sylvestris (Gmelin) Hegi, the European Wild Grape and ancestor of cultivated grapevine varieties (V. vinifera L. ssp. vinifera) is the sole wild grapevine species existing in Europe. This important crop wild relative (CWR) species is almost extinct, and persists only in residual habitats. Since these habitats are close to vineyards, this CWR species is endangered by hybridisation with its descendant crop and naturalised rootstocks that originate from viticulture. For this reason, we addressed two questions: To what extent have the remaining South German European Wild Grape accessions escaped hybridisation and preserved genetic identity? Second, what is the potential of this CWR species as a genetic resource for breeding in relation to several grapevine diseases? Using a set of highly resolving genetic markers, we were able to exclude introgression of autochthonous sylvestris accessions by cultivated grapevine. However, we detected introgression mostly from wild American species used as rootstocks in viticulture. The autochthonous accessions can be grouped into clusters. Comparative inoculation studies with the grapevine pathogens powdery mildew (Erysiphe necator), downy mildew (Plasmopara viticola), and black rot (Guignardia bidwellii) revealed relatively high levels of resistance in some of the ssp. sylvestris accessions and represents a valuable genetic resource for resistance breeding.

Authors: Schröder, S. et al.

Publication Year: 2015

ABSTRACT: The world's wealth of plant genetic resources has much value for world food security, but these resources are under considerable threat. Crop improvement, particularly under climate change, depends on the genetic diversity of our plant genetic resources, which are arguably inadequately conserved and poorly used. There is wide recognition that the Convention on Biological diversity's 2010 targets to reduce the loss of biodiversity have not been met. biodiversity is at risk from multiple threats, including climate change, and the genetic diversity contained within plant genetic resources, particularly of species that are wild relatives of our crops, faces similar threats but is essential to our ability to respond to the new stresses in the agricultural environment resulting from climate change. It is important to consider the genetic value of these crop wild relatives, how they may be conserved, and what new technologies can be implemented to enhance their use.

Authors: Ford-Lloyd, B.V. et al.

Publication Year: 2011

ABSTRACT: Pigeonpea [Cajanus cajan (L.) Millsp.] is a versatile, stress-tolerant, and nutritious grain legume, possess- ing traits of value for enhancing the sustainability of dry sub-tropical and tropical agricultural systems. The use of crop wild relatives (CWR) in pigeonpea breeding has been successful in providing important resistance, quality, and breeding efficiency traits to the crop. Current breeding objectives for pigeonpea include increasing its tolerance to abiotic stresses, including heat, cold, drought, and waterlogging. Here we assess the potential for pigeonpea CWR to be further employed in crop improvement by compiling wild species occurrence and ex situ conservation information, producing geographic distribution models for the species, identifying gaps in the comprehensiveness of current germplasm collections, and using ecogeographic information to identify CWR populations with the potential to contribute agronomic traits of priority to breeders. The fifteen prioritized relatives of pigeonpea generally occur in South and South- east Asia to Australia, with the highest concentrations of species in southern India and northern Australia. These taxa differ considerably among themselves and in comparison to the crop in their adaptations to temperature, precipitation and edaphic conditions. We find that these wild genetic resources are broadly under-represented in ex situ conservation systems, with 80% of species assessed as high priority for fur- ther collecting, thus their availability to plant breeders is insufficient. We identify species and highlight geographic locations for further collecting in order to improve the completeness of pigeonpea CWR germ- plasm collections, with particular emphasis on potential traits for abiotic stress tolerance.

Authors: Khoury, K. et al.

Publication Year: 2015

ABSTRACT: Sophisticated computational methods have been developed to help us to identify sets of nature reserves that maximize the representation of regional diversity, but, until recently, the methods have not dealt explicitly and directly with the main goal of reserve networks, that of the long-term maintenance of biodiversity. Furthermore, the successful application of current methods requires reliable information about species distributions, which is not always available. Recent results show that data quality, as well as the choice of surrogates for biodiversity, could be critical for successful reserve design. Because of these problems and a lack of communication between scientists and managers, the impact of computational site-selection tools in applied conservation planning has been minimal.

Authors: Cabeza, M. and Moilanen, A.

Publication Year: 2001

Authors: Eldarov, M., et al.

Publication Year: 2014

ABSTRACT: Crop wild relatives of sweetpotato [Ipomoea batatas (L.) Lam., I. series Batatas] have the potential to contribute to breeding objectives for this important root crop. Uncertainty in regard to species boundaries and their phylogenetic relationships, the limited availability of germplasm with which to perform crosses, and the difficulty of introgression of genes from wild species has constrained their utilization. Here, we compile geographic occurrence data on relevant sweetpotato wild relatives and produce potential distribution models for the species. We then assess the comprehensiveness of ex situ germplasm collections, contextualize these results with research and breeding priorities, and use ecogeographic information to identify species with the potential to contribute desirable agronomic traits. The fourteen species that are considered the closest wild relatives of sweetpotato generally occur from the central United States to Argentina, with richness concentrated in Mesoamerica and in the extreme Southeastern United States. Currently designated species differ among themselves and in comparison to the crop in their adaptations to temperature, precipitation, and edaphic characteristics and most species also show considerable intraspecific variation. With 79% of species identified as high priority for further collecting, we find that these crop genetic resources are highly under-represented in ex situ conservation systems and thus their availability to breeders and researchers is inadequate. We prioritize taxa and specific geographic locations for further collecting in order to improve the completeness of germplasm collections. In concert with enhanced conservation of sweetpotato wild relatives, further taxonomic research, characterization and evaluation of germplasm, and improving the techniques to overcome barriers to introgression with wild species are needed in order to mobilize these genetic resources for crop breeding.

Authors: Khoury, K. et al.

Publication Year: 2015

ABSTRACT: Genetic diversity of crop species in sub-Sahelian Africa is still poorly documented. Among such crops, pearl millet is one of the most important staple species. In Niger, pearl millet covers more than 65% of the total cultivated area. Analyzing pearl millet genetic diversity, its origin and its dynamics is important for in situ and ex situ germplasm conservation and to increase knowledge useful for breeding programs. We developed new genetic markers and a high-throughput technique for the genetic analysis of pearl millet. Using 25 microsatellite markers, we analyzed genetic diversity in 46 wild and 421 cultivated accessions of pearl millet in Niger. We showed a significantly lower number of alleles and lower gene diversity in cultivated pearl millet accessions than in wild accessions. This result contrasts with a previous study using iso-enzyme markers showing similar genetic diversity between cultivated and wild pearl millet populations. We found a strong differentiation between the cultivated and wild groups in Niger. Analyses of introgressions between cultivated and wild accessions showed modest but statistically supported evidence of introgressions. Wild accessions in the central region of Niger showed introgressions of cultivated alleles. Accessions of cultivated pearl millet showed introgressions of wild alleles in the western, central, and eastern parts of Niger.

Authors: Mariac, C. et al.

Publication Year: 2006

Authors: Zaharieva, M., et al.

Publication Year: 2004

Authors: Cadima, X. et al.

Publication Year: 2014

ABSTRACT: Crop wild relatives have a long history of use in potato breeding, particularly for pest and disease resistance, and are expected to be increasingly used in the search for tolerance to biotic and abiotic stresses. Their current and future use in crop improvement depends on their availability in ex situ germplasm collections. As these plants are impacted in the wild by habitat destruction and climate change, actions to ensure their conservation ex situ become ever more urgent. We analyzed the state of ex situ conservation of 73 of the closest wild relatives of potato (Solanum section Petota) with the aim of establishing priorities for further collecting to fill important gaps in germplasm collections. A total of 32 species (43.8%), were assigned high priority for further collecting due to severe gaps in their ex situ collections. Such gaps are most pronounced in the geographic center of diversity of the wild relatives in Peru. A total of 20 and 18 species were assessed as medium and low priority for further collecting, respectively, with only three species determined to be sufficiently represented currently. Priorities for further collecting include: (i) species completely lacking representation in germplasm collections; (ii) other high priority taxa, with geographic emphasis on the center of species diversity; (iii) medium priority species. Such collecting efforts combined with further emphasis on improving ex situ conservation technologies and methods, performing genotypic and phenotypic characterization of wild relative diversity, monitoring wild populations in situ, and making conserved wild relatives and their associated data accessible to the global research community, represent key steps in ensuring the long-term availability of the wild genetic resources of this important crop.

Authors: Castañeda-Álvarez, N.P. et al.

Publication Year: 2015

ABSTRACT: Organic farming is based on the concept of working ‘with nature’ instead of against it; however, compared with conventional farming, organic farming reportedly has lower productivity. Ideally, the goal should be to narrow this yield gap. In this review, we specifically discuss the feasibility of new breeding techniques (NBTs) for rewilding, a process involving the reintroduction of properties from the wild relatives of crops, as a method to close the productivity gap. The most efficient methods of rewilding are based on modern biotechnology techniques, which have yet to be embraced by the organic farming movement. Thus, the question arises of whether the adoption of such methods is feasible, not only from a technological perspective, but also from conceptual, socioeconomic, ethical, and regulatory perspectives.

Authors: Andersen, M.M. et al.

Publication Year: 2015

ABSTRACT: The reasons why some plant species were selected as crops and others were abandoned during the Neolithic emergence of agriculture are poorly understood. We tested the hypothesis that the traits of Fertile Crescent crop progenitors were advantageous in the fertile, disturbed habitats surrounding early settlements and in cultivated fields. We screened functional traits related to competition and disturbance in a group of grass species that were increasingly exploited by early plant gatherers, and that were later domesticated (crop progenitors); and in a set of grass species for which there is archaeological evidence of gathering, but which were never domesticated (wild species). We hypothesised that crop progenitors would have greater seed mass, growth rate, height and yield than wild species, as these traits are indicative of greater competitive ability, and that crop progenitors would be more resilient to defoliation. Our results show that crop progenitors have larger seed mass than wild species, germinate faster and have greater seedling size. Increased seed size is weakly but positively correlated with a higher growth rate, which is primarily driven by greater biomass assimilation per unit leaf area. Crop progenitors also tend to have a taller stature, greater grain yield and higher resilience to defoliation. Collectively, the data are consistent with the hypothesis that adaptations to competition and disturbance gave crop progenitors a selective advantage in the areas surrounding early human settlements and in cultivated environments, leading to their adoption as crops through processes of unconscious selection.

Authors: Cunniff, J. et al.

Publication Year: 2014

ABSTRACT: It is essential to illuminate the evolutionary history of crop domestication in order to understand further the origin and development of modern cultivation and agronomy; however, despite being one of the most important crops, the domestication origin and bottleneck of soybean (Glycine max) are poorly understood. In the present study, microsatellites and nucleotide sequences were employed to elucidate the domestication genetics of soybean.

Authors: Guo, J. et al.

Publication Year: 2010

ABSTRACT: Micronutrient malnutrition, particularly zinc and iron deficiency, afflicts over three billion people worldwide due to low dietary intake. In the current study, wild emmer wheat (Triticum turgidum ssp. dicoccoides), the progenitor of domesticated wheat, was tested for (1) genetic diversity in grain nutrient concentrations, (2) associations among grain nutrients and their relationships with plant productivity, and (3) the association of grain nutrients with the eco-geographical origin of wild emmer accessions.

Authors: Chatzav, M. et al.

Publication Year: 2009

Authors: Watanabe, N., et al.

Publication Year: 2005

ABSTRACT: Locating and quantifying genetic variation within crop wild relatives is an ongoing activity of gene banks tasked with ex situ conservation. Without detailed information about the population genetics of a species, geography often serves as a reasonable proxy for differentiation. With this in mind, this paper examines the genetic diversity and differentiation of Beta vulgaris subsp. maritima accessions collected along a well-studied latitudinal gradient along the French Atlantic coast of France as well as Corsica, for use as representative genotypes from the Mediterranean basin. The aim of this work is to identify the scale and magnitude of differentiation and diversity in this set of accessions, using both molecular and quantitative traits. We assessed clinal variation and admixture in genetic and morphometric data along this latitudinal gradient. Results from this study revealed a complex pattern of recent gene flow and immigration on a historical biogeographic structure. Our data suggest that a presumed latitudinal cline is in reality an admixed mosaic of genotypes.

Authors: Richards, C. et al.

Publication Year: 2013

ABSTRACT: Describing genetic diversity in wild barley (Hordeum vulgare ssp. spontaneum) in geographic and environmental space in the context of current, past and potential future climates is important for conservation and for breeding the domesticated crop (Hordeum vulgare ssp. vulgare). Spatial genetic diversity in wild barley was revealed by both nuclear- (2,505 SNP, 24 nSSR) and chloroplast-derived (5 cpSSR) markers in 256 widely-sampled geo-referenced accessions. Results were compared with MaxEnt-modelled geographic distributions under current, past (Last Glacial Maximum, LGM) and mid-term future (anthropogenic scenario A2, the 2080s) climates. Comparisons suggest large-scale post-LGM range expansion in Central Asia and relatively small, but statistically significant, reductions in range-wide genetic diversity under future climate. Our analyses support the utility of ecological niche modelling for locating genetic diversity hotspots and determine priority geographic areas for wild barley conservation under anthropogenic climate change. Similar research on other cereal crop progenitors could play an important role in tailoring conservation and crop improvement strategies to support future human food security.

Authors: Russell, J. et al.

Publication Year: 2014

ABSTRACT: In this study, inter-simple sequence repeats (ISSR) ans simple sequence repeat (SSR) markers were used to investigate genetic diversity of 27 mulberry accessions including 19 cultivated accessions (six M. multicaulis, three M. alba, two M. atropurpurea, two M. bombycis, one M. australis, two M. rotundiloba, one M. alba var. pendula, one M. alba var. macrophylla, and one M. alba var. venose) and 8 wild accessions (two M. cathayana, two M. laevigata, two M. wittiorum, one M. nigra and one M. mongolica). ISSRs and SSRs were compared in terms of their informativeness and efficiency in a study of genetic diversity and relationships among 27 mulberry genotypes. SSRs presented a higher level of polymorphism and greater information content. All index values of genetic diversity both markers analyzed using Popgene 32 software indicated that within wild species had higher genetic diversity than within cultivated species. Cultivation may caused the lose of genetic diversity of mulberry compared with wild species revealed by ISSR and SSR markers. The mean genetic similarity coefficients among all mulberry genotypes ascribed by ISSR and SSR matrices were 0.7677 and 0.6131, respectively. For all markers a high similarity in dendrogram topologies was obtained although some differences were observed. Cluster analysis of ISSR and SSR using UPGMA method revealed that the wild species are genetically distant from the domesticated species studied here. The correlation coefficients of similarity were statistically significant for both marker systems used. Principal coordinates analysis (PCA) for ISSR and SSR data also supports their UPGMA clustering. These results have an important implication for mulberry germplasm characterization, improvement, molecular systematics and conservation.

Authors: Weiguo, Z. et al.

Publication Year: 2006

ABSTRACT: Identification of ecogeographic parameters associated with genetic variation would help to prioritize populations within conserved species for collection and maintenance. Previous studies comparing accessions of three Solanum species representing different breeding systems, S. fendleri A. Gray (a disomic polyploid selfer), S. jamesii Torr. (a diploid outcrosser), and S. sucrense Hawkes (a polysomic polyploid outcrosser), revealed no significant associations between genetic and ecogeographic variation. Even physical separation did not predict genetic distance. These previous studies are expanded here by investigating the relationship of genetics and geographic parameters for a fourth type of breeding system: a diploid selfer, modeled by wild S. verrucosum Schlechtd (2n = 2x = 24) from Mexico. The objective was to assess whether genetic distances between accessions are predicted by differences in geographic parameters at the natural sites of origin. Twenty-seven S. verrucosum accessions were studied using 152 RAPD markers to estimate the genetic distance between pairs of accessions. The association of genetic variation with proximity of the S. verrucosum accessions to other Mexican wild potato species (some known to be sympatric with S. verrucosum) was also analyzed. Pairwise comparisons showed that the average GD of all pairs of accessions was 12.8% (ranging from 0–29.3%). Parameters with variation significantly correlated with the average GD of S. verrucosum populations were physical separation (0.42), latitude (0.70), longitude (0.51), proximity to S. hjertingii Hawkes (0.80), S. hougasii Corr. (−0.75), and S. demissum Lindl. (−0.50). Significant effects of proximity to S. hjertingii (for example) might be caused by introgression, or the coincidence that all S. hjertingii occur in the extreme NE corner of the S. verrucosum range.

Authors: Del Rio A. H., and Bambergb, J. B.

Publication Year: 2003

ABSTRACT: Premise of the study: Wild populations of domesticated species constitute a genetic reservoir and are fundamental to the evolutionary potential of species. Wild papaya (Carica papaya) is a rare, short-lived, gap-colonizing, dioecious tree that persists in the forest by continuous dispersal. Theoretically, these life-history characteristics render wild papaya highly susceptible to habitat fragmentation, with anticipated negative effects on its gene pool. Further, species dioecy may cause founder effects to generate local biases in sex ratio, decreasing effective population size. We contrasted the genetic diversity and structure of C. papaya between wild populations from rainforest fragments and continuous forest at Los Tuxtlas, Mexico. We evaluated recent migration rates among populations as well as landscape resistance to gene flow. Finally, we calculated the sex ratio of the populations in both habitats. Populations of wild papaya in rainforest fragments showed lower genetic diversity and higher population differentiation than populations in continuous rainforest. Estimates of recent migration rates showed a higher percentage of migrants moving from the continuous forest to the forest fragments than in the opposite direction. Agricultural land and cattle pasture were found to be the most resistant matrices to gene flow. Finally, biased sex ratios were seen to affect the effective population size in both habitats.The mating system, rarity, and short life cycle of C. papaya are exacerbating the effects of rainforest fragmentation on its genetic diversity, threatening the persistence of its natural populations in the proposed place of origin as well as its genetic reservoir.

Authors: Chávez-Pesqueira, M. et al.

Publication Year: 2014

ABSTRACT: Recognized as a priority three decades ago, in situ conservation of crop wild relatives has developed theoretical and methodological focus and achieved significant on-the-ground progress in the last 10 years, most notably under the impetus of the plant genetic resources community. Literature and Internet searches and interviews with experts were undertaken as a basis for reviewing the current status and trends of this effort worldwide. Country-by-country summaries on in situ crop wild relatives conservation activities are presented, and recommendations are made for future action. Principal recommendations include ‘flagging’ of appropriate taxa as crop wild relatives in botanical and conservation databases, undertaking gap analyses to locate crop wild relatives hotspots, and enhancing cooperation between the plant genetic resources and plant conservation communities.

Authors: Meilleur, B. and Hodgkin, T.

Publication Year: 2004

ABSTRACT: Genetic diversity is the fundamental level of biological diversity. In the discussion of biological diversity in agricultural ecosystems, this level is of major importance, but often neglected. Tools for the direct measurement of genetic diversity, especially in highly diverse systems such as permanent grassland, are demanding and the relationship between genetic diversity and management practices or environmental factors is poorly understood. Genetic diversity of the common grassland species Dactylis glomerata was assessed using genetic diversity indices based on 29 SSR markers. Phenotypic diversity within and among selected populations was evaluated in a replicated field experiment based on ten phenotypic plant characters of agronomic relevance. Twenty populations of D. glomerata from permanent grassland from the Swiss Alps were included in the analysis. We investigated correlations between genetic diversity (genotypic/phenotypic) and farming system (conventional/organic), management intensity (intensive/extensive), three plant species diversity indices, five ecological and five habitat parameters at collection sites. Genetic and phenotypic variability within and among populations of D. glomerata was large. The intensive management of permanent grassland reduced genotype diversity and genetic variation of the plant character ‘flowering time’, while conventional farming systems increased the average expected heterozygosity within populations of D. glomerata. Populations from extensively managed sampling sites accommodated significantly smaller D. glomerata individuals. SSR markers and phenotypic characters proved to be valuable tools for the assessment of genetic and phenotypic diversity considering different perspectives. Management parameters were the main factors influencing genotypic diversity and phenotypic characteristics in natural populations of D. glomerata in permanent grassland.

Authors: Last, L. et al.

Publication Year: 2014

ABSTRACT: The genetic relationships between the wild and cultivated melon accessions from Northwest and Central China were dissected using 22 microsatellite markers. A total of 153 alleles, a high level of expected heterozygosity (0.669), and a low observed heterozygosity (0.156) were detected in the total panel. Differences on the allelic composition and heterozygosity levels were found between the two accession types and the wild accessions revealed a higher level of genetic diversity. The UPGMA analysis of the total panel showed that (a) most wild accessions from Northwest China were clustered independently from the cultivated accessions, and (b) the wild and cultivated accessions from Central China presented a high genetic closeness and showed a divergence from those of Northwest China. Similar positioning of the most accessions was observed with the principal coordinate analysis and STRUCTURE analysis. Pairwise FST and Nei's genetic distance quantified the genetic differentiation among the different accession types and further verified our findings. We concluded that the wild melons from Northwest China have a distinctive genetic background and could be the true wild forms, while the wild melons from Central China showed a close relationship to the local cultivars and could be a return from the cultivated melons in the same region. Our results offer an insight into the genetic resources of the main melon producing regions in China, which is essential for maximizing utilization of the traits of interest in wild melons.

Authors: Hu, J. et al.

Publication Year: 2014

Authors: Sreejith, U., et al.

Publication Year: 2003

Species prioritization is a crucial step in any development of conservation strategy, especially for crop wild relatives (CWR), since financial resources are generally limited. This study aimed at: assessing the biodiversity of crop wild relatives in Benin and identifying priority species for active conservation. Data were collected through literature review to establish an exhaustive list of CWR in Benin. Eight prioritization criteria and different prioritization systems were used. The top 50 species obtained by each of these methods were identified and twenty final top CWR were shortlisted as those occurring as priority across methods. A total of 266 plant species belonging to 65 genera and 36 families were identified. The most represented are: Cyperaceae (12.50 %), Leguminosae-Papilionoideae (11.87 %), Convolvulaceae (11.25 %), Poaceae (10.31 %), Asteraceae (7.81 %), Solanaceae (6.87 %) and Dioscoreaceae (5.31 %). Among the 20 species of highest priority for conservation, Manihot glaziovii Müll. Arg. and Piper guineense Schumach. et Thonn., appeared as the most represented species on top of the list.

Authors: Idohou, R. et al.

Publication Year: 2012

Authors: Magos Brehm, J., et al.

Publication Year: 2010

Authors: Shishido, R., et al.

Publication Year: 2006

ABSTRACT: Berberidopsis corallina Hook. f. (Berberidopsidaceae) is a threatened vine, endemic to the temperate rain forests of southern Chile. A RAPD analysis was carried out to assess the extent of genetic variation in remaining wild populations and in British cultivated plants, to assess the value of the latter for ex situ conservation. A total of 90 individuals (54 wild, 35 cultivated) were analysed, and a total of 54 polymorphic bands produced. A pairwise distance measure calculated from the RAPD data was used as input for principal coordinate analysis (PCO) and analysis of molecular variance (AMOVA). AMOVA indicated that an exceptionally high proportion of total genetic variation (54.8%) was recorded among populations; pairwise FST comparisons showed that all the populations examined were signicantly (P 5 0.002) di€erent. PCO analysis highlighted clear di€erentiation between wild populations from the north and south of the natural range, further supported by a UPGMA dendrogram based on RAPD distances. Analysis of the extent of genetic variation within ex situ populations indicated that the variation within plants cultivated within Britain is comparable to that recorded in small natural populations; however, cluster and UPGMA analyses suggested that only populations from the northern part of the natural range of the species are represented in cultivation. These results are interpreted in the context of the recent biogeographical history of the area, and their implications for the development of in situ and ex situ conservation strategies for B. corallina are discussed.

Authors: Etisham-ul-haq, M. et al.

Publication Year: 2001

ABSTRACT: Because the conservation of biodiversity occurs under time and resource constraints, it is necessary to prioritize species most deserving of attention. Natural history collections have been identified as a valuable source of information in applied conservation practice, particularly for species-rich taxa like plants. Here, online herbarium information was combined with a novel, straightforward priority setting approach to screen a large list of rare vascular plant species (n = 418) in Saskatchewan, Canada. Data was quantified to develop priority scores (for a given species) using three key criteria: (1) provincial responsibility in species survival, (2) species local population characteristics, and (3) the anthropogenic threats causing species to be rare. The use of a hierarchy of the three criteria, wherein provincial responsibility was assigned the most weight, resulted in the highest ranking for 13 species that exist only in Saskatchewan and no other Canadian province or territory. The list is a first step in identifying species deserving of conservation attention and/or further study, while the method itself was deemed to be highly relevant to conservation managers and decision makers due to its scale adaptability and fairly minimal resource requirements.

Authors: Kricsfalusy, V.V. and Trevisan, N.

Publication Year: 2013

ABSTRACT: Pulsatilla patens (L.) Mill. (Ranunculaceae) is a threatened plant which in Fennoscandia favours south-facing, warm slopes of pine-dominated esker forests. The cessation of cattle grazing, modern forestry practices, and especially efficient fire prevention have resulted in closure of undergrowth vegetation in these forests. Using generalized linear models (GLM), we studied the relationships between habitat factors (covers of field and ground layer and amount of litter) and the population structure of P. patens in 48 populations in Finland in order to identify favourable conditions for regeneration. The largest populations occurred at sites with intermediate values of both ground and field layer. The number of juvenile plants was also highest at intermediate values of ground layer. Dense moss layer and abundant litter had a negative effect on the flowering of P. patens. In conclusion, creation and maintenance of habitat heterogeneity to prevent the closure of undergrowth vegetation is of paramount importance for the successful reproduction of P. patens.

Authors: Kalliovirta, M. et al.

Publication Year: 2006

Authors: Beharav, A., et al.

Publication Year: 2014

Authors: Vikas, V.K., et al.

Publication Year: 2014

ABSTRACT: Current extinction rates of plant and animal species are estimated to be as much as 100- to 1000-fold higher than during the recent geological past, a phenomenon that conservation biologists attribute to wide-scale destruction of natural habitats (Pimm et al. 1995). As natural habitats continue to disappear, there have been increasing efforts to stockpile wild plant species in large, centralized seed banks a form of conservation that falls under the general category of ex situ conservation, or conservation outside the native habitat.

Authors: Schoen, D. J. and Brown, A.H.D.

Publication Year: 2001

Authors: Davidar, P., et al.

Publication Year: 2015

Authors: Hajjar, R. and Hodgkin, T.

Publication Year: 2007

ABSTRACT: Growing concern over the potentially devastating impacts of climate change on biodiversity and food security, considered together with the growing world population, means that taking action to conserve crop wild relative (CWR) diversity is no longer an option—it is an urgent priority. Crop wild relatives are species closely related to crops, including their progenitors, which have the potential to contribute beneficial traits for crop improvement, such as biotic and abiotic resistances, leading to improved yield and stability. Having already made major contributions to crop improvement in the 20th century,CWR are recognized as a critical resource to sustain global food security; therefore, their systematic conservation is imperative. However, extending their conservation and promoting more systematic exploitation is hindered by a lack of understanding of their current and potential value, their diversity, and practically how they might be conserved. Therefore, the aim of this paper is to (i) demonstrate the current and potential use of CWR in crop improvement, (ii) estimate how many CWR species exist and how many are a global priority for active conservation, and (iii) describe how a global network for the in situ conservation of CWR might be established that could help to underpin future food security.

Authors: Maxted, et al.

Publication Year: 2011

ABSTRACT: Dramatic changes in climatic conditions, exhibited as heat waves, water scarcity and heavy rains, continue to threaten crop quality and yield. Additionally, fungal-based plant pathogen booming is another reflection of climate change creating some potential risks for agricultural production of main staple crop species. Most of the abiotic and biotic stresses are under the control of complex traits. Moreover, a wide range of desirable quantitative characters in cultivated crops, such as disease resistance, might degenerate with time. Therefore, buffering crops against the large environmental changes is important for feeding the world’s increasing population and requires implementation of effective food security strategies. Crop biodiversity plays a key role in the improvement of stress tolerant species and enables an extensive platform for identification of novel traits by using a range of molecular tools. This offers homozygous crop models for the traits of interest, prediction models related to the stress tolerance and genetic resources for the transformation of cultivated crops. This review provides an overview for application of different crop wild relatives and demonstrates their roles on development of stress tolerant plants. It also highlights the importance of global crop conservation and alternative plant species for future plant breeding.

Authors: Yumurtaci, A.

Publication Year: 2015

ABSTRACT: We studied wild and semi-wild leafy vegetables used by the Maale and Ari ethnic communities in southern Ethiopia. Quantitative and qualitative ethnobotanical methods, including individual and focus group (n = 18) discussions, field observations, and individual interviews (n = 144), were used in three rural kebeles (lowest administrative unit). The two ethnic communities consumed 30 leafy vegetable species grouped into 22 genera and 15 families. The study participants underlined that wild and semi-wild leafy vegetables are important components in traditional dishes, more frequently during periods of food shortage. The communities showed high preference for Balanites aegyptiaca and Solanum dasyphyllum in the Maale and Ari study sites respectively. Taste, marketability and above ground edible biomass were farmers’ main selection criteria suitable for leafy vegetables cultivation. The transfer of local knowl- edge within the community on wild and semi-wild leafy vegetables is not differentiated by gender or age and thus enables knowledge continuity, although harvesting and cooking activities are considered as women’s tasks by the communities. Major threats to wild and semi-wild leafy vegetables need to be minimized and complementary in-situ and ex situ conservation strategies scaled up.

Authors: Kidane, B. et al.

Publication Year: 2015

ABSTRACT: Knowledge of mating systems is required in order to understand the genetic composition and evolutionary potential of plant populations. Outcrossing in a population may co-vary with the ecological and historical factors influencing it. However, literature on the outcrossing rate is limited in terms of wild sorghum species coverage and eco-geographic reference. This study investigated the outcrossing rates in wild sorghum populations from different ecological conditions of Kenya. Twelve wild sorghum populations were collected in four sorghum growing regions. Twenty-four individuals per population were genotyped using six polymorphic simple sequence repeat (SSR) markers to compute their indirect equilibrium estimates of outcrossing rate as well as population structure. In addition, the 12 populations were planted in a field in a randomised block design with five replications. Their progeny (250 individuals per population) were genotyped with the six SSR markers to estimate multi-locus out- crossing rates. Equilibrium estimates of outcrossing rates ranged from 7.0 to 75.0%, while multi-locus outcrossing rates (tm) ranged from 8.9 to 70.0% with a mean of 49.7%, indicating that wild sorghum exhibits a mixed mating system. The wide range of estimated outcrossing rates in wild sorghum populations indicate that environmental conditions may exist under which fitness is favoured by outcrossing and others under which selfing is more advantageous. The genetic structure of the populations studied is concordant with that expected for a species displaying mixed mating system.

Authors: Muraya, M.M. et al.

Publication Year: 2011

ABSTRACT: South Africa is endowed with wide varieties of biodiversity among which are wild vegetable species of remarkable nutritious qualities like macro and micronutrients, minerals and vitamins. However, there is still a high prevalence of malnutrition; especially micronutrients deficiencies, a phenomenon described as hidden hunger, among low or marginal income bracket of the population. The use of wild vegetables has variously been proposed as part of the major solutions to solving the problems of micronutrient malnutrition among these populations. Unfortunately, the utilisation of wild vegetables among South Africans is in the decline due to over reliance on exotic species. The Agricultural Research Council of South Africa and other stake holders have conducted studies on some aspects of these vegetables. However, there are still a lot of information gaps in certain aspects of these important indigenous resources especially in northern KwaZulu, which need some research attention. Critical among these are: Population genetics of the species in the wild, agronomic evaluation under different growing conditions and phytochemical evaluation of these important species in order to encourage the overall use of these important indigenous resources.

Authors: Lewu, F. B. and Mavengahama, S.

Publication Year: 2010

ABSTRACT: All processes that regulate of growth, differentiation and development and also stomatal movement are influenced by endogenous hormones in plants. Research related with endogenous hormones is known for cultivated chickpea (Cicer arietinum L.), while in wild chickpeas no data existed. In this study, C. bijugum K.H. Rech.; C. chorassanicum (Bge) M. Pop.; C. cuneatum Hochst. ex Rich.; C. echinospermum P.H. Davis; C. judaicum Boiss.; C. pinnatifidum Jaub. et Sp.; C. reticulatum Ladiz.; and C. yamashitae Kitamura were evaluated for variations in endogenous plant hormone concentrations; indole-3-acetic acid, zeatin, gib- berellic acid, and abscisic acid in both leaf and pod. It was concluded that there was a great variation on endogenous plant hormones among the annual wild Cicer species. The data may support selection for various attributes.

Authors: Toker, C. et al.

Publication Year: 2006

ABSTRACT: The legume pod borer, Helicoverpa armigera (Hu ̈ bn.), is one of the major constraints to chickpea production, and host plant resistance is an important component for the management of this pest. The levels of resistance in the cultivated chickpea are low to moderate, and therefore, we evaluated 17 accessions of perennial Cicer along with three cultivated chickpea genotypes for resistance to H. armigera. There was a significant reduction in both leaf feeding and larval weights when the larvae were fed on the leaves of Cicer microphyllum Benth. accessions ICC 17146, ICC 17236, ICC 17240, and ICC 17248. Relative resistance index based on leaf feeding, larval survival, and larval weight indicated that C. microphyllum accessions ICC 17146, ICC 17236, ICC 17234, ICC 17240, ICC 17243, and ICC 17248 were highly resistant to H. armigera. Under natural infestation, accessions belonging to C. microphyllum, C. canariense Santos Guerra et Lewis, and C. macracanthum M. Pop suffered a damage rating of <2.0 compared to 4.0 in C. judaicum Boiss. accession ICC 17148 (annual species) and 8.5–9.0 in the cultivated chickpeas (1 = <10% leaf area damaged, and, 9 = >80% leaf area damaged). There was considerable diversity in the accessions belonging to perennial wild species of chickpea, and these can be exploited to increase the levels and diversify the basis of resistance to H. armigera in the cultivated chickpea.

Authors: Sharma, H. C. et al.

Publication Year: 2006

ABSTRACT: Lentil anthracnose (Colletotrichum truncatum (Schwein.) Andrus et W.D. Moore is a potential threat in many lentil (Lens culinaris Medik.) production regions of North America. In the lentil germplasm maintained in Germany and North America, 16 lines were reported to have resistance to race Ct1, but none has resistance reported to race Ct0. The objective of this study was to examine accessions of wild Lens species for their resistance to races Ct1 and Ct0 of lentil anthracnose. Five hundred and seventy-four wild ac- cessions of six species and control lines were screened in two replications under both field and greenhouse conditions using a 1–9 scoring scale (1, highly resistant; 2–3, resistant; 4–5, moderately resistant; 6–7, susceptible; and 8–9, highly susceptible). Indian head and PI 320937 were resistant while Eston and Pardina were susceptible to race Ct1 as expected. However, none of the check lines were resistant to race Ct0. Among the six Lens wild species tested, accessions of Lens ervoides (Brign.) Grande had the highest level of resistance, 3–5 to race Ct1 and Ct0 followed by L. lamottei Czefr. in the field and greenhouse. Lens orientalis (Boiss.), L. odemensis L., L. nigricans (M. Bieb.) Godron and L. tomentosus L. were highly susceptible, 8–9 to race Ct0 in the greenhouse. The highest frequency of resistance, especially in L. ervoides (Brign.) Grande, was found in accessions originating from Syria and Turkey. The usefulness of these L. ervoides (Brign.) Grande accessions as sources of resistance to the more virulent race of anthracnose in a lentil breeding program is discussed.

Authors: Tullu, A. et al.

Publication Year: 2005

Authors: Prosperi, J.M., et al.

Publication Year: 2006

ABSTRACT: Myrtus communis L. (Myrtaceae), in Tunisia, is closely associated with Quercus suber L. forest which stretched continuously from the North to parts of Cap Bon and Tunisian Dorsal. The destruction of the primary oak forests associated to an over-exploitation of Myrtus for its essential oil quality had led to discontinuous populations exhibiting various levels of degradation. Using starch gel electrophoresis, we analyzed the polymorphism of nine isozymes in order to assess genetic diversity and structuring of 17 natural populations prospected in the three geographical regions and coinciding with subhumid, humid inferior and semi-arid superior bioclimates. The analysis of the level and the distribution of the genetic diversity in this species might help in its conservation. Out of the 18 loci detected for all populations and isozymes analyzed, 12 loci were polymorphic. Allelic frequencies differed according to populations and particular alleles characterized ecological groups. A high level of genetic variation within populations was observed. The mean number of alleles per polymorphic locus was Ap = 1.67, the percentage of polymorphic loci was P = 60.3% and the observed (Ho) and the expected (He) heterozygosities were respectively 0.144 and 0.215. Populations belonging to subhumid (Cap Bon) and semi-arid superior (Tunisian Dorsal) climates, located in degraded sites exhibited the highest level of inbreeding (0.425 < FIS < 0.450). A high level of differentiation (FST = 0.396) and a low gene flow (Nm = 0.337) among populations, as a result of habitat intermediate destruction, were revealed. The differentiation of populations within the same bioclimate (or geographic) group was substantial and relatively higher for semi-arid superior populations (FST = 0.262), which were more distant. The three ecological groups exhibited a high level of structuring (FST = 0.401). These differentiations might be due to geographic distances and to the variations of ecological factors between sites, including human activities and environmental factors. Nei’s (1972) genetic distances calculated between pairs of populations were globally low (0.006 < D < 0.367) with a mean of 0.15. They indicate a high level of similarity between populations. UPGMA clustering, established through Nei’s genetic distances, showed three population aggregates according to their geographic/bioclimatic appartenances. The high differentiation between populations and the low level of their genetic divergence indicated their recent isolation under anthropic pressures. The species conservation (in situ or ex situ) strategies should take into account the genetic diversity level within populations and its variation between geographic groups.

Authors: Messaoud, C. et al.

Publication Year: 2006

ABSTRACT: Cañahua (Chenopodium pallidicaule Aellen) is a poorly studied, annual subsistence crop of the high Andes of South America. Its nutritional value (high in protein and mineral content) and ability to thrive in harsh climates make it an important regional food crop throughout the Andean region. The objectives of this study were to develop genetic markers and to quantify genetic diversity within cañahua. A set of 43 wild and cultivated cañahua genotypes and two related species (Chenopodium quinoa Willd. and Chenopodium petiolare Kunth) were evaluated for polymorphism using 192 microsatellite markers derived from random genomic cañahua sequences produced by 454 pyrosequencing of cañahua genomic DNA. Another 424 microsatellite markers from C. quinoa were also evaluated for cross-species amplification and polymorphism in cañahua. A total of 34 polymorphic microsatellite marker loci were identified which detected a total of 154 alleles with an average of 4.5 alleles per marker locus and an average heterozygosity value of 0.49. A cluster analysis, based on Nei genetic distance, clearly separated from wild cañahua genotypes from the cultivated genotypes. Within the cultivated genotypes, subclades were partitioned by AMOVA analysis into six model-based clusters, including a subclade consisting sole of erect morphotypes. The isolation by distance test displayed no significant correlation between geographic collection origin and genotypic data, suggesting that cañahua populations have moved extensively, presumably via ancient food exchange strategies among native peoples of the Andean region. The molecular markers reported here are a significant resource for ongoing efforts to characterize the extensive Bolivian and Peruvian cañahua germplasm banks, including the development of core germplasm collections needed to support emerging breeding programs.

Authors: Vargas, A. et al.

Publication Year: 2010

Authors: Mallikarjuna, N., et al.

Publication Year: 2010

ABSTRACT: The subgenus Archaesolanum is a group composed of eight species with a characteristic chromosome number based on n = x = 23 and an area restricted to the South Pacific. This subgenus is an isolated group of Solanum for which extensive information about phylogenetic relationships based on molecular genetic methods is lacking. This study represents an approach to analyze genetic relationships within this group. In this context, seven species were examined using random amplified polymorphic DNA (RAPD) markers. In further analysis, the amplification products of two chloroplast regions (trnS-trnG and rbcL) were studied with polymerase chain reaction (PCR) restriction fragment length polymorphism (RFLP) method. Screening for the presence of unique mitochondrial rearrangements was also carried out using universal mitochondrial primers for the detection of fragment length polymorphisms. We identified two major groups within the subgenus; one was composed of the members of ser. Avicularia and Laciniata, while the other was formed by species belonging to ser. Similia. It is suggested that the taxonomic status of series within the Archaesolanum clade should be revised. The hybrid origin of S. laciniatum was also tested, and two hypotheses regarding its phylogeny are assumed.

Authors: Poczai, P. et al.

Publication Year: 2011

ABSTRACT: South Africa has a rich flora which exhibits among the highest species density in the world, distributed across nine biomes that support an impressive diversity of animal life. However, a variety of human actions, invasion by alien species, natural disturbances and climate change collectively impact negatively on the great diversity of both plant and animal species. In situ conservation has long been practised, primarily in nature reserves, complemented by ex situ conservation in national botanic gardens, but in vitro plant conservation is not common. In the context of animal biodiversity conservation, the Wildlife Biological Resource Centre of the National Zoological Gardens utilises cryobanking as one of its major focuses and is now poised to expand as the repository for the cryoconservation of plant germplasm, particularly for indigenous recalcitrant-seeded and poor-seeding species. However, there are particular problems associated with successful germplasm cryostorage of such tropical and subtropical plants. As we see the science and application of cryobiology and cryoconservation as cross-cutting and transdisciplinary, we have entrained formal networking among scientists offering a range of specialisations aimed at a deeper understanding of common problems and practical outcomes to facilitate both plant and animal biobanking. The endeavours are aimed at elucidating the basis of both successes and failures in our efforts to attain optimal outcomes. With focus on best practices, standard operating procedures, validation and risk management for cryopreserved and cold-stored plant and animal material, our ultimate aim is to facilitate restoration by the safe reintroduction of indigenous species.

Authors: Berjak, P et al.

Publication Year: 2010

ABSTRACT: The Tehuacán Valley in Mexico is a principal area of plant domestication in Mesoamerica. There, artificial selection is currently practised on nearly 120 native plant species with coexisting wild, silvicultural and cultivated populations, providing an excellent setting for studying ongoing mechanisms of evolution under domestication. One of these species is the columnar cactus Stenocereus pruinosus, in which we studied how artificial selection is operating through traditional management and whether it has determined morphological and genetic divergence between wild and managed populations.

Authors: Parra, F. et al.

Publication Year: 2010

Authors: Akopian, J., et al.

Publication Year: 2010

ABSTRACT: Salinity is an abiotic stress that limits both yield and the expansion of agricultural crops to new areas. In the last 20 years our basic understanding of the mechanisms underlying plant tolerance and adaptation to saline environments has greatly improved owing to active development of advanced tools in molecular, genomics, and bioinformatics analyses. However, the full potential of investigative power has not been fully exploited, because the use of halophytes as model systems in plant salt tolerance research is largely neglected. The recent introduction of halophytic Arabidopsis-Relative Model Species (ARMS) has begun to compare and relate several unique genetic resources to the well-developed Arabidopsis model. In a search for candidates to begin to understand, through genetic analyses, the biological bases of salt tolerance, 11 wild relatives of Arabidopsis thaliana were compared: Barbarea verna, Capsella bursa-pastoris, Hirschfeldia incana, Lepidium densiflorum, Malcolmia triloba, Lepidium virginicum, Descurainia pinnata, Sisymbrium officinale, Thellungiella parvula, Thellungiella salsuginea (previously T. halophila), and Thlaspi arvense. Among these species, highly salt-tolerant (L. densiflorum and L. virginicum) and moderately salt-tolerant (M. triloba and H. incana) species were identified. Only T. parvula revealed a true halophytic habitus, comparable to the better studied Thellungiella salsuginea.Major differences in growth, water transport properties, and ion accumulation are observed and discussed to describe the distinctive traits and physiological responses that can now be studied genetically in salt stress research.

Authors: Orsini, F. et al.

Publication Year: 2010

ABSTRACT: We applied proteomics analysis to generate a map of the wild relatives of wheat grain proteins. These differentially expressed proteins are potentially involved in metabolism, stress responses, and other biological activities. Using two-dimensional electrophoresis, we detected 119, 134, and 193 reproducible spots on gels loaded with protein samples extracted from the A, B, and D genomes, respectively, of the mature grain. In all, 89, 53, and 54 distinct proteins, respectively, were found among these genomes through MALDI-TOF mass spectrometry. Of these, 26% (n = 52) proteins were considered distinct. They included 18.89% (n = 17) in the A, 28.30% (n = 15) in the B, and 37.04% (n = 20) in the D genome, all functioning in disease and defense roles. For example, the ABA-inducible protein PHVA1 can be induced by drought, cold, heat, and salinity, while the basic endochitinase confers protection against chitin-containing fungal pathogens. The diverse functional categories found here suggest different biological processes, such as disease/defense, energy metabolism, protein synthesis and storage, cellular organization, signal transduction, transcription, and the facilitation of transport. Our findings demonstrate that these functional proteins have important roles in stress tolerance and the maintenance of quality in mature grains. The interacting effects of genetics and environment on differential protein production may be partially mediated by a regulatory mechanism in those grains.

Authors: Kim, K.-H. et al.

Publication Year: 2010

ABSTRACT: The establishment of priorities among species is a crucial step in any conservation strategy since financial resources are generally limited. Traditionally, priorities for conservation of plant species have been focused on endemicity, rarity and particularly on their threatened status. Crop wild relatives (CWR) and wild harvested plants (WHP) are important elements of biodiversity with actual or potential socio-economic value. In this study, eight prioritisation criteria were used along with different prioritisation systems and applied to the Portuguese CWR and WHP. The top 50 species obtained by each of these methods were identified. The final top CWR were those that occurred as a priority in most methods. Twenty CWR were identified as the highest priorities for conservation in Portugal and they include wild relatives of the crop genera Allium, Daucus, Dianthus, Epilobium, Festuca, Herniaria, Narcissus, Quercus, Plantago, Trifolium, and Vicia. Eighteen WHP were recognised as priorities for conservation and include several Narcissus and Thymus species, among others. The advantages, limitations and level of subjectivity of each of the methods used in this exercise are discussed.

Authors: Brehm, J.M. et al.

Publication Year: 2010

ABSTRACT: The increasing awareness of the effects of climate change on plant distributions in situ has made the appropriate application of ex situ techniques more crucial. These ex situ conservation techniques need to be targeted to priority species identified at risk from climate change. The present paper assesses the sensitivity of plant species to climate change in Belgium and explores the current conservation status of those species potentially vulnerable to climate change. We then checked whether these species were included in ex situ collections. The whole Belgian flora has been assessed (a total of 1,396 native plant species). We evaluated whether each of these species occurs in a “climate change-vulnerable” habitat, having therefore a higher probability to be impacted by climate change. The assessment revealed that there are at least 415 native plant species (30% of the Belgian native flora) that appear to be vulnerable to climate change during the next decades. Results also showed that about one-third of the species currently included in the red list may have their situation made potentially worse due to climate change. In addition, depending on the region, between 45 and 67% of the species that are currently not threatened in Belgium are likely to become so due to climate change. It also appeared that only 32% of these climate change-vulnerable species are currently held ex situ. We conclude that there is a need to identify gaps in existing ex situ collections as an urgent priority and ensure that species potentially vulnerable to climate change are conserved ex situ.

Authors: Godefroid, S. et al.

Publication Year: 2010

Authors: Xie, J., et al.

Publication Year: 2009

ABSTRACT: Little is known about the genetic diversity of pale flax (Linum bienne Mill.), the wild progenitor of cultivated flax (L. usitatissimum L.), and ex situ germplasm of pale flax was scarce. Effort was made to collect 34 pale flax accessions and five landrace accessions of cultivated flax in Turkey. The inter simple sequence repeat (ISSR) technique was applied to characterize this set of flax germplasm, along with one Turkish cultivar, one Russian cultivar, five winter and four dehiscent type accessions of cultivated flax. Twenty-four ISSR primer pairs detected a total of 311 DNA fragments, of which 298 bands were polymorphic across 493 flax samples (roughly 10 samples per accession). These polymorphic bands had frequencies ranging from 0.002 to 0.998 and averaging 0.38. Accession-specific ISSR variation (Fst values) ranged from 0.469 to 0.514 and averaged 0.493. There was 49.3% ISSR variation resided among these 50 accessions, 35.9% harbored among landrace, winter, dehiscent types of cultivated flax and pale flax, and 38.2% present among 34 pale flax accessions. Pale flax displayed more ISSR variation than landraces and dehiscent type, but less than winter type, of cultivated flax. Clustering 493 individual plants revealed that these assayed plants were largely grouped according to their plant types and that pale flax was genetically more close to the dehiscent type, followed by the winter type and landrace, of cultivated flax. Pale flax collected within the geographic range of 180 km displayed a significant spatial genetic autocorrelation. Genetic distances among the pale flax accessions were significantly associated with their geographic distances and elevation differences. These findings are significant for understanding flax domestication and its primary gene pool.

Authors: Uysal, H. et al.

Publication Year: 2010

ABSTRACT: In Nepal, in traditional rice farming systems many diverse landraces are grown in all of the rice agro-ecosystems from low to high altitude. Three case study sites were selected to represent the major rice agro-ecozones: Bara (100–150 m) for the low-altitude terai (plain); Kaski (700–1,206 m) for the mid-hill zone; and Jumla (2,200–3,000 m) for the high-hill zone. The diversity in rice varieties was compared in these three sites and nine survey villages in a series of surveys conducted in 1998, 1999 and 2006. The level and distribution of diversity on farm varied with the physical and socio-economic settings of the farming communities. The mid-hill site (Kaski) had the highest rice landrace diversity. This was adapted to the diverse agro-ecosystems found there and there was equal diversity in Kule khet (irrigated lands by seasonal canals) and Sim khet (marshy wet land). The next most diverse system was Nicha khet (irrigated lowlands) in Bara, the low-altitude site. The high-hill site (Jumla) had the lowest rice diversity. Across all sites many of the landraces were rarely grown and then only in small areas, reflecting the specialized uses to which they were put. At all sites the most common single landrace occupied less than half of the rice area. Resource-rich farmers were the more important custodians of on-farm rice varietal diversity across the sites. There was more rice diversity in favourable environments than in less favourable ones. This was true whether diversity was measured across sites or across rice domains within sites.

Authors: Bajracharya, J. et al.

Publication Year: 2010

Authors: Olivera, P.D., et al.

Publication Year: 2010

ABSTRACT: Historic populations of crop species outside their centers of origin and diversity, like the domestic olive (Olea europaea L.) in North America, are genetic resources for contemporary agriculture, including genotypes that could be readily evaluated for, and may be adapted to, local conditions. The primary goal of this study was to describe the diversity and structure of several significant, adjacent, contemporaneous historic olive plantings in central coastal California, USA with reference to the USDA ex situ Olea europaea germplasm, and test the hypothesis that physical and chronological proximity are predictive of genetic similarity in those trees. The groups studied using 14 SSR markers were dominated by a limited number of genotypes represented in the USDA collection, but also four unique cultivar genotypes not in that collection. Historical socioeconomic networks appear to have had an important influence on the source and kind of material planted. This is the first study of historic olive trees conserved in situ in North America and provides the basis for a larger regional study integrating genetic, historical and geographic data to describe the structure and diversity of remaining historic olive plantings in California.

Authors: Soleri, D et al.

Publication Year: 2010

ABSTRACT: Drought and salinity are the major abiotic stresses that dramatically threaten the food supply in the world. Tribe Triticeae, including wheat and barley, possesses tremendous potential for drought and salt tolerance that has been extensively and practically identified, tested, and transferred to wheat cultivars with proven expression of tolerance in experimental trials. Triticum dicoccoides and Hordeum spontaneum, the progenitors of cultivated wheat and barley, have adapted to a broad range of environments and developed rich genetic diversities for drought and salt tolerances. Drought- and salt-tolerant genes and quantitative trait loci (QTLs) have been identified in T. dicoccoides and H. spontaneum and have great potential in wheat and barley improvement. Advanced backcross QTL analysis, the introgression libraries based on wild wheat and wild barley as donors, and positional cloning of natural QTLs will play prevailing roles in elucidating the molecular control of drought and salt tolerance. Combining tolerant genes and QTLs in crop breeding programs aimed at improving tolerance to drought and salinity will be achieved within a multidisciplinary context. Wild genetic resistances to drought and salinity will be shifted in the future from field experiments to the farmer.

Authors: Nevo, E. & Guoxiong Chen

Publication Year: 2010

ABSTRACT: Daucus carota subsp. halophilus, is a wild crop relative of domestic carrot. It is an aromatic plant widely used in folk medicine due to recognized therapeutic properties of its essential oils. Experiments were carried out to evaluate the potential of in vitro propagation techniques to the conservation of this endemic and endangered taxon. The results showed that shoot tips of in vitro germinated seeds were able to proliferate in the presence of benzyladenine, with the best results being achieved using 4.4µM, both in the first and second cultures. Shoots rooted after being transferred to 1/2- Murashige and Skoog basal medium. The results indicated that the concentration of benzyladenine used during the multiplication phase did not interfere with the rate of root formation. The obtained plantlets were morphologically and anatomically identical to those obtained by seeds. Some of the in vitro produced shoots developed flowers that produced viable pollen. Plant regeneration was also achieved by somatic embryogenesis induction in cotyledons and root segments cultured in the presence of 4.5µM 2,4-dichlorophenoxyacetic acid. Somatic embryos converted into plantlets in a medium without growth regulators. Plants obtained either by shoot proliferation or somatic embryogenesis were acclimatized and are now growing at the Coimbra Botanical Garden. The first attempts to reintroduce these plants in the original habitat were successful. It can be concluded that the protocols developed are a useful approach to the conservation of this endemic species.

Authors: AT Tavares, LR Salgueiro, JM Canhoto

Publication Year: 2010

ABSTRACT: Cassava (Manihot esculenta Crantz) roots spoil 2 to 3 d after harvest because of postharvest physiological deterioration (PPD), which has remained an unsolved problem. Roots from different sources of germplasm were evaluated 5, 10, 20, and 40 d after harvest and some were found to be tolerant to PPD. Three genotypes showed zero levels of PPD even 40 d after harvest. Tolerance to PPD in roots with high carotenoid levels may be explained by their antioxidant properties. Irradiation of seeds in mutagenized populations may have silenced one of the genes involved in the expression of PPD. The tolerance to PPD found in other sources cannot be properly explained. The identification of several sources of resistance (and at least two different modes of action) suggests that now there are alternatives available for solving this problem, benefiting millions of resource-limited farmers worldwide.

Authors: Morante, N. et al.

Publication Year: 2009

ABSTRACT: Knowledge of the genetic and demographic consequences of rarity is crucial when evaluating the effects of habitat loss and fragmentation on population viability, and for creating management plans in rare plant species. Reduction in population size and in the number of populations can lead to decreased genetic diversity and increased inbreeding. Genetic diversity is often correlated with fitness and is frequently used to identify populations of greatest conservation concern, or those that may be good candidates for ex situ conservation programs. However, an association between these factors is not always clear, and crossing studies evaluating whether there is phenotypic differentiation among populations in fitness related traits can inform managers of suffering populations or good sources for ex situ materials. Crossing studies can also evaluate the potential for genetic rescue to boost fitness in suffering populations. To address these questions, we conducted two generations of controlled crosses between populations of the extremely rare and fragmented sunflower, Helianthus verticillatus. We measured achene viability, germination, survival, and pollen viability (F1 only) in 176 F1 and 159 F2 families. The populations were differentiated with respect to phenotypic fitness measures with one population having significantly lower achene viability and germination. Also, the potential for genetic rescue was observed as gene flow into the less fit population resulted in higher fitness measures in both the F1 and F2. Results are discussed with respect to the importance of combining genetic marker data with crosses and the implications for conservation in disjunct populations of rare species.

Authors: Ellis, R. & McCauley D.E.

Publication Year: 2009

ABSTRACT: Germplasm collections are valuable gene pools providing diverse genetic material that may be applied for the improvement of cultivars and advanced agronomic productivity. An assessment of genetic and genomic diversity within these collections can be used to assign lines and populations to diverse groups; to study the evolutionary history of wild relatives; to verify pedigrees and fill in the gaps in incomplete pedigree or selection history, to monitor changes in allele frequencies in cultivars or populations and to help narrow the search for new alleles at loci of interest. Towards the application of genetic diversity analysis to Brassica germplasm improvement, we are characterising genetic diversity between 28 species and wild relatives of Brassica from an international germplasm collection, using 60 Simple Sequence Repeat (SSR) molecular markers. Results on the SSR polymorphism and phylogenetic relationship among species and wild relatives of Brassica will be presented.

Authors: Redden, R. et al.

Publication Year: 2009

ABSTRACT: The levels of resistance to shoot fly, Atherigona soccata in sorghum germplasm are low to moderate and therefore, we evaluated 17 wild relatives of sorghum under field and greenhouse conditions as an alternate source of genes for resistance to this pest. Thirty-two accessions belonging to Parasorghum, Stiposorghum and Heterosorghum did not suffer any shoot fly damage under multi-choice conditions in the field, while one accession each of Heterosorghum (Sorghum laxiflorum) and Chaetosorghum (S. macrospermum) suffered very low shoot fly damage. Accessions belonging to S. exstans (TRC 243601), S. stipoideum (TRC 243399) and S. matarankense (TRC 243576) showed absolute non-preference for oviposition under no-choice conditions. Accessions belonging to Heterosorghum, Parasorghum and Stiposorghum were preferred for oviposition, but suffered low deadheart formation. Manual infestation of seedlings with shoot fly eggs did not result in deadheart formation in some of the accessions belonging to S. exstans (TRC 243601), S. stipoideum (TRC 243399), S. matarankense (TRC 243576) and S. purpureosericeum (IS 18944). Larval mortality was recorded in main stems of the Parasorghums. Within section Sorghum, accessions belonging to S. bicolor ssp. verticilliflorum were highly susceptible to shoot fly, as were those of S. halepense. However, a few accessions such as IS 18226 (race arundinaceum) and IS 14212 (S. halepense) resulted in reduced survival and fecundity. Wild relatives of sorghum exhibited very high levels of antibiosis to A. soccata, while only low levels of antibiosis have been observed in the cultivated germplasm. Therefore, wild relatives with different mechanisms of resistance can be used as a source of alternate genes to increase the levels and diversify the basis of resistance to shoot fly, A. soccata.

Authors: Kamala, V. et al.

Publication Year: 2009

ABSTRACT: The composition and structure of 300 enset gardens from 10 different locations in Sidama were examined. Average size of the gardens was 0.74 ha. The gardens are composed of mixtures of various named enset varieties and different groups recognisable on the basis of ‘sex’ (male and female) and use (cooking and processing). The gardens exhibit high diversity, with a given garden containing up to 24 varieties (mean = 8.2). However, the components are not represented equally. Typically, the gardens consisted of one or two very abundant varieties and a much larger number of less common ones. Enset gardens are dynamic because the number and composition of varieties and different types changed from garden to garden, from location to location and across time. Their composition, structure and dynamics have been influenced by human, socio-economic factors (farm size, land per capita, cropping patterns and size of livestock), temporal circumstances and landscape elements (elevation) in which they are found. The nature, characteristics, organization and functions of Sidama enset gardens are outlined and the importance of maintaining mixtures of varieties for farmers is discussed.

Authors: Tesfaye, B.

Publication Year: 2008

ABSTRACT: The development of sugar beet as an economically important field crop coincided with our increased understanding of modern genetic principles. It was developed in the late 1700s from white fodder beet; therefore, the genetic base of sugar beet is thought to be narrower than many open-pollinated crops. The wild sea beet is the progenitor of all domesticated beet and cross compatible with cultivated beet (domestic and cultivated are given subspecies level in the same species). The breeding system of sugar beet is complex and the crop is biennial, which lengthens the generation time to almost 1 year. A genetic-cytoplasmic male sterility (CMS) system is utilized for commercial hybrid production. Early breeding objectives were to improve the concentration and extractability of sucrose and little emphasis was placed on host–plant resistance to insect, nematode, and disease pests. As production areas expanded, these pests limited production, sometimes severely. The first systematic attempts to screen exotic and wild beet germplasm for disease resistance were initiated early in the 20th century. Many undesirable traits from wild beet were reportedly introgressed with the selected disease resistance and it was only in the late 1900s that the use of wild beet genetic resources became common place in public breeding programs. In North America, a pivotal development in utilizing the genetic resources available for sugar beet breeding was the formation in 1983 of the Sugarbeet Crop Germplasm Committee (CGC). Since the Sugarbeet CGC identified enhancing the commercial sugar beet germplasm pool as a high priority, there has been an aggressive evaluation of the National Plant Germplasm System (NPGS) Beta collection. This collection now has more than 2500 accessions from within the genus Beta. In 2002, it was estimated that close to 25,000 evaluation data points (descriptors × accessions evaluated) describing the collection were available in the Genetic Resources Information Network (GRIN) database. Over 3000 evaluations described levels of resistance of sugar beet and wild beet accessions to 10 major disease and insect pests of sugar beet. As soon as the evaluation data are collected, they are used to select the sources for the pre-breeding programs. There is a lag time in sugar beet of␣8–15 years between starting a germplasm development program and releasing the first germplasm, but successes of this program are available in the germplasm released to the commercial breeders. Resistance genes from wild beet for rhizomania and beet cyst nematode resistance have been commercialized.

Authors: Panella, L. et al.

Publication Year: 2007

Authors: Maxted, N.

Publication Year: 2003

Genetic resources contain the natural gene pool responsible for yield, natural pests resistance, adaptation for the environmental stresses and other desirable traits. The approaches of conservation depend on the nature of the conserved material, the objective of conservation, and the scope of conservation, mass reservoir and in vitro conservation. These approaches can be used very effectively for the conservation of the wild communities, forage plant, primitive cultivars, land races, sexual and asexual plants.

Authors: Sammour, R.H.

Publication Year: 1993