Setting conservation priorities for crop wild relatives in the Fertile Crescent

The aim of this paper is to contribute directly to the systematic, long-term conservation of crop wild relatives (CWR) in the Fertile Crescent by setting conservation priorities to secure and improve CWR conservation in situ and ex situ as a means of underpinning global food security. We established the first priority list of CWR within the Fertile Crescent following several criteria comprising production value (m × p), projected production value (m × p), production area (ha), projected production area (ha), native status, energy supply (kcal/capita/day), protein supply (g/capita/day), fat supply (g/capita/day), occurrence status, gene pool, taxon group, and threat status. An inventory of 220 priority CWR was established for the Fertile Crescent region. We followed twelve prioritisation approaches and assessed 21,080 species. About 4% of the total species (835 species) were identified as CWR that have socio-economic value for the region. These 835 CWR species were prioritised to create the CWR priority list which consisted of 220 species (1% of the total species assessed). The majority of the CWR priority list (185 species) were related to cereal, vegetable, and industrial crops and 35 of them are related to fruits and trees. The CWR priority list includes crop wild relatives of the genera Aegilops (20 species), Lactuca (11 species), Avena (11 species), Carthamus (11 species), Allium (9 species), Thinopyrum (10 species), and Triticum (3 species). We present the first inventory of 220 priority CWR for the Fertile Crescent. The inventory helps to improve in situ and ex situ conservation and the genetic diversity of CWR. Both the inventory and the methodology applied in prioritisation can be used in setting national, regional, and global conservation strategies. The recommendations will help the Fertile Crescent meet its targets in conserving CWR diversity as well as making sure that CWR genetic resources are preserved to prevent and tackle global food insecurity.     

Development of national crop wild relative conservation strategies in European countries

To generate European-wide information to contribute to the improvement of national and regional crop wild relative (CWR) conservation planning and the development of effective CWR conservation strategies, a questionnaire was sent to the members of the Wild Species Conservation in Genetic Reserves Working Group of the European Cooperative Programme for Plant Genetic Resources (ECPGR) to collate information on progress in developing and implementing national CWR conservation strategies and action plans. Responses from 30 countries were analysed and literature sources were consulted to fill some information gaps. Results showed that 13 countries were in the preparation stage of their national strategies, i.e. having no drafts prepared yet, 14 in higher stages (from the first draft prepared to the published and approved ones), and three have not yet started the planning process. Twelve countries included all categories of species autochthony (i.e., native, archaeophyte and neophyte) in their priority CWR lists. Wild relatives of human and animal food crops were selected as the highest priorities by 23 and 22 countries, respectively. Relative level of threat was identified as the most important prioritization criterion by 23 countries. Italy reported the highest number of CWR in its national checklist (10,779 taxa) and priority list (1118 taxa), whereas Ireland reported the lowest number of CWR in its checklist (171 taxa) and Portugal reported the lowest number in its priority list (20 taxa). Regarding the percentages of prioritized CWR, the strictest approach was applied in Portugal—only 20 out of 2262 CWR taxa, or < 1%, were selected as priorities for conservation action, whereas in Spain 578 out of 929 CWR taxa, or about 62% were prioritized. Eleven countries have proposed the establishment of genetic reserves, from one per country (Israel) to an extended network (Germany and the Netherlands). Only the UK had a formally established genetic reserve. The highest number of priority CWR taxa that occur in existing protected areas was reported by Spain—472 species, or 82% of the national priority list, whereas the lowest number—14 species, or 70% of the national priority list—in Portugal. Israel reported the highest number of priority CWR taxa (319 or 98%) conserved in gene banks. Among the limitations in the development of national CWR strategies highlighted by countries, was the lack of an EU agency responsible for genetic resources. The development of CWR conservation strategies is mostly within the domains of agriculture (13 countries) and environment (12 countries), although both domains are involved in eight countries. The most successful results in the development and implementation of CWR conservations strategies are achieved in the countries where multiple stakeholders, including ministries, research institutions, NGOs, local communities, protected area authorities and national PGR committees are involved. Some discussion and conclusions regarding further developments are provided.     

Development of a national crop wild relative conservation strategy for Cyprus

Growing research interest in crop wild relatives (CWR) has highlighted their value for crop improvement, particularly to mitigate the impact of climate change and contribute to global food security. As most conservation activities are implemented at national level there is a requirement for each country to develop and implement a national CWR conservation strategy. This will contribute to regional and global CWR conservation actions and so help achieve CBD Aichi Targets 13 of improved genetic conservation of socio-economically important taxa. Cyprus has historically lacked systematic CWR conservation but is rich in CWR diversity being located in the eastern Mediterranean Vavilov centre and abutting the Fertile Crescent. Therefore a more coherent approach to CWR conservation is desirable. From an initial checklist of 1,722 Cypriot CWR taxa, 178 CWR were prioritized and eco geographic data was collated and analysed using GIS techniques. The Troodos and Pafos mountains are CWR hotspots and ten priority sites containing the genetic diversity of 74.7 % of priority CWR taxa were identified. These will form the basis of a national network of in situ genetic reserves and 78 priority CWR taxa that have no accessions in the national Cyprus gene bank are highlighted for collection and ex situ storage.     

Towards the conservation of crop wild relative diversity in North Africa: checklist,prioritisation and inventory

Crop wild relatives (CWR) are wild species that are more or less genetically related to crops that can be used to introgress useful genes for improvement of productivity, resistance to biotic and abiotic stresses and quality of cultivated crops. They are important in crop improvement to achieve food security for an increasing population and to overcome the challenges caused by climate change and the new virulence of major diseases and pests. These genetic resources are increasingly threatened in their natural habitats through over-exploitation and land reclamation and degradation. Therefore, their efficient and effective conservation would be taxonomically and genetically valuable and will contribute to maintaining and promoting the sustainability of crop diversity, facilitating agricultural production and supporting the increasing demand for food, feed and natural resources. A checklist of 5780 Crop Wild Relatives (CWR) taxa from North Africa was obtained using the CWR Catalogue for Europe and the Mediterranean (PGR Forum). Of which consists 76% of the flora of North Africa. The checklist contains 5588 (~97%) native taxa and 192 introduced. Families with higher taxa richness are Fabaceae, Asteraceae, and Poaceae. These three families constitute more than 33% of the total taxa included in the checklist. About 9% (502) CWR taxa identified as a priority for conservation in North Africa using four criteria, the economic value of the crop, the relatedness degree of wild relatives to their crop, threat status using IUCN red list assessment, and finally the centre of origin and/or diversity of the crop. Of these, 112 taxa were assigned high, 268 medium and 122 low priorities for effective conservation. Those assessed as threatened using IUCN Red list and national assessment represent approximately 2% (119 taxa) of the CWR in the region. However, 21 taxa are assessed as critically endangered (CR), 53 as endangered (EN), and 45 as vulnerable (VU). Wild relatives of some globally important crops are present, with those related to wheat (Triticum aestivum L. and T. durum L.) and barley (Hordeum vulgare L.) among the highest priority crops for the North Africa region. Amongst CWR assessed as threatened, only 8 (6.7%) CWR are related to food crops, Avena agadiriana B.R. Baum. et G. Fedak (VU), A. atlantica B.R. Baum et G. Fedak (VU), A. murphyi Ladiz. (EN), Beta macrocarpa Guss. (EN), Olea europaea subsp. maroccana Guss. (VU), Rorippa hayanica Maire (VU) and Aegilops bicornis (Forssk.) Jaub. et Spach (VU). The wild relative of Safflower Carthamus glaucus M. Bieb is restricted to Egypt and Libya and assessed as rare in Egypt. The information available about the conservation and threat status of CWR in North Africa still lags behind, and more investigations are required.     

A problem of the rich: Prioritizing local plant genetic resources for ex situ conservation in Israel

A priority list of 323 plant species was created through a consultative process for ex situ conservation in the recently inaugurated Israel Plant Gene Bank (IGB). The IGB is set up to preserve plant genetic resources and the endangered genetic variability of the Israeli flora. Upon its inauguration, we consulted with the country’s leading plant breeders and botanists in an attempt to create a list of the most important plant species to be included in the initial collections. The list includes crop wild relatives (CWRs), selected according to their contribution to humans: edible plants (grains, vegetables, oil); forage plants; species with potential industrial and biotechnological applications (e.g. spices, medicinal plants, aromatic plants, fibers, dyes), and species with horticultural and forestry potential. We further ranked the species on the basis of assessed values for each of seven characteristics: distribution range in the country; abundance; rarity of the growing habitats; endemism; red number index—representing imminent threat of extinction; availability of samples in Israeli collections, and genetic relationship to cultivated crops. The sum of the assessed values for these seven characteristics was used to group the species on the list into four main prioritized-collection schemes. Statistical analysis indicated that all attributes had similar influence on the collecting prioritization scheme. In general, rare species with low abundance in their growing habitats were ranked in the highest priority group, while highly distributed species were sorted together into a lower priority group. The prioritization scheme will be used to optimize the collection in the IGB with the aim of establishing its collecting activities.     

Crop wild relatives in Andaman and Nicobar Islands,India

Andaman and Nicobar Islands, India is a geographically insulated biodiversity rich centre in tropical region. The islands are endowed with huge plant diversity comprising of 3219 species of 299 families and 1251 genera. The present study aimed to develop a systematic list of crop wild relatives (CWR) in the islands using information from available literature and also by ground survey. A total of 38 visits were made in all three districts of the islands and observed the crop wild relatives. In total, 153 wild species from 76 genera of 27 families were found to be related to crop plants. The list includes 34 endemic and 4 species of rare occurrence. These species are vital constituent of gene pool which can be explored for rare but novel traits of economic significance. Wild species were found to be abundant in Anacardiaceae, Musaceae, Fabaceae, Zingiberaceae, Myristicaceae, Orchidaceae and Cucurbitaceae. The listed CWRs have potential to create variability and diversify the genebanks. These CWRs grow well in tropical islands in spite of prevalent biotic and abiotic stresses. The information documented will be useful for germplasm exploration, pre-breeding and devising strategies for conservation.     

National inventory and prioritization of crop wild relatives in Spain

Crop wild relatives (CWR) have recently received significant attention due to their value as plant genetic resources and their contribution to world food security. We present a prioritized checklist of CWR in Spain in which the criteria of crossability with crops of economic importance, endemicity and threat status have been taken into account. First, we selected a list of genera corresponding to the most relevant crops for Spain and at the international level. These crops were classified into use categories (Food, Forage & Fodder, Ornamental, and Industrial & Other uses) depending on their main use. The wild plant species native to Spain belonging to these genera were then listed. After evaluation by national experts in plant breeding, the resulting checklist contained 929 species. Further selection based on crossability, endemicity and threat status led to the generation of the Prioritized Spanish Checklist of crop wild relatives containing 578 species. Thirty-two percent of these species belong to the Forage & Fodder use category, 28% to the Ornamental category, 24% to the Food category and 16% to the Industrial & Other uses category. Thirty-five percent of the prioritized species are endemic to Spain, and over one-fourth are classified under some category of threat according to the International Union for Conservation of Nature. Endemicity and threat status rates in the Prioritized Spanish Checklist of CWR were higher than those found in the prioritized CWR inventories of other countries. A ex situ assessment reporting number of accessions showed that 70% of the prioritized Spanish CWR have accessions preserved in genebanks.     

National inventories of crop wild relatives and wild harvested plants: case-study for Portugal

Crop wild relatives (CWR) and wild harvested plant species (WHP) constitute an important element of a nation’s plant genetic resources (PGR) available for utilisation. Although their natural populations are threatened like other wild species by habitat lost and fragmentation, little attention has generally been paid to their systematic conservation. The development of checklists and inventories is considered by the convention on biological diversity (CBD) and the global strategy for plant conservation (GSPC) as the first step in any national strategy for conservation and sustainable use of plant diversity. Methodological approaches to the development of a national inventory of wild PGR are discussed in the light of a case-study for the CWR and WHP growing in mainland Portugal. The resultant inventory comprises 2319 taxa, of which 97.5% are CWR, 21.4% are WHP and 19.0% are both CWR and WHP. Approximately 6.1% are endemic to mainland Portugal; 24.1% occur in 1 to 4 Portuguese administrative regions; 15.6% are threatened, but only 5.9% are covered by legislative protection. Taxonomic misalignments and the dispersed nature of biological literature were the major impediments to the production of the national inventory, but once the inventory was established it has proven to be a powerful tool in conservation management.     

Home gardens: an assessment of their biodiversity and potential contribution to conservation of threatened species and crop wild relatives in Benin

Despite growing literature supporting the importance of home gardens (HG) as biodiversity hotspots, knowledge of patterns of their contribution to conservation of threatened species and crop wild relatives (CWR) across climate and culture in Africa is still limited. This investigation was conducted across three climatic zones to assess the floristic diversity of home gardens and the extent to which they contribute to conservation of threatened species and CWR. Overall, 240 home gardens were sampled and their floristic diversity assessed. The ecological importance of recorded species was determined per climatic zone using the importance value index (IVI). A cluster analysis was performed to group the species according to their IVI-values and a principal component analysis helped to identify the most important species. 285 species were inventoried throughout the study area. Home garden species’ diversity globally declined from the drier to the wetter zone but was highest in the transition zone. The average number of species found per HG was 10.1 and varied weakly across zones (9.07, Guineo-Congolean zone; 10.77, Sudano-Guinean zone; and 10.53, Sudanian zone). The most important home gardens species in the Sudanian, the Sudano-Guinean and the Guineo-Congolean zones were respectively: Abelmoschus esculentus (L.) Moench and Hibiscus asper Hook.f.; Solanum lycopersicum L. and Zea mays L.; Ipomoea aquatica Forssk. and Senna occidentalis (L.) Link. They were mainly vegetables and used as food and/or medicinal plant species. Twenty CWR and twelve threatened species were recorded and were also mainly used for food and medicinal purposes. Thorough research on socioeconomic factors supporting possession of HG and choice of managed species as well as indigenous management strategies of HG and dynamic of traditional knowledge related to HG may help to deeply assess home gardens’ effectiveness in biodiversity conservation.     

Genetic diversity and species delimitation in the cultivated and wild Guinea yams (Dioscorea spp.) from Southwest Ethiopia as determined by AFLP (amplified fragment length polymorphism) markers

Yams (Dioscorea spp.) rank as the fourth most important root and tuber crop after potatoes, cassava and sweet potatoes. They are an economic crop in most of the tropics especially in West Africa, which produces over 95 % of the world output. Despite their cultural and economic importance there is taxonomic confusion regarding Guinea yams. The currently used classification scheme, which relies on vegetative and inflorescence characters, does not consistently delimit species boundaries between members of Guinea yams (D. cayenensis Lam.–D. rotundata Poir. complex), their wild relatives (D. abyssinica Kunth and D. praehensilis Benth.,) and D. sagittifolia Pax. Establishing the taxonomic identity of the germplasm and understanding the systematic relationships among crops is vital to the management of genetic resources and the utilization of accessions. In this study, amplified fragment length polymorphism (AFLP) genetic fingerprinting was used to evaluate and characterize 43 individual plants, belonging to different populations of wild and cultivated Guinea yams. The three primer combinations used in the AFLP analyses generated 158 scorable bands, with an overall polymorphism of 78 %. Ordination and cluster analyses of AFLP data failed to produce any clear species boundary between either the Guinea yam accessions or between them and their wild relatives. The average genetic similarity between the study individuals of Guinea yams and their wild relatives ranged from 60 to 100 %. The first, second and third principal coordinates axes cumulatively account for 77.45 % of the total variation. AFLP analyses also revealed a higher genetic divergence among cultivated Guinea yam accessions of the Sheko cultivars. Ordination and cluster analysis using UPGMA revealed no clear species boundaries between members of the complex. Thus, the taxonomy of these “species” needs to be revisited using other markers.     

Inventory of related wild species of priority crops in Venezuela

A prerequisite in any conservation programme of Plant Genetic Resources is estimation of diversity. The inventory of wild and naturalized relatives of priority crops in Venezuela (CWR) is based on the main Catalogues of Flora in the country, selecting taxa closely related to crops, according to the concepts of “gene pool” and “taxonomic group”. We included 47 genera, 217 species and 228 taxa belonging to 28 plant families. Among them, those with higher richness are: Fabaceae, Solanaceae, Araceae, Lauraceae, Dioscoreaceae, Poaceae, Rosaceae and Myrtaceae. Genera with a higher number of species are Xanthosoma, Persea, Dioscorea, Prunus, Psidium, Phaseolus, Solanum, Vigna, Capsicum, Manihot, Theobroma, Ipomoea and Oryza. A total of 26 endemic species are found, which belong to genera Xanthosoma, Persea, Dioscorea, Prunus and Manihot. The primary gene pool of crops include native species from genera such as Manihot, Solanum (Section Petota), Lycopersicon, Ananas, Capsicum, Dioscorea, Xanthosoma, Phaseolus, Theobroma, Ipomoea, Gossypium, Arracacia and Psidium. Genera with native species weakly related to crops are Saccharum, Persea, Ipomoea, Prunus, Vigna, Solanum (Section Melongena) and Daucus. Crop genera without native species in Venezuela are Allium, Musa, Brassica, Spinacia, Helianthus, Pisum, Lactuca, Citrus, Elaeis, Beta, Glycine and Triticum. Only a few taxa have already been evaluated according to the IUCN criteria, and Venezuelan accessions of crop wild relatives in national and international genebanks are very scarce.     

Treasuring crop wild relative diversity: analysis of success from the seed collecting phase of the ‘Adapting Agriculture to Climate Change’ project

The seed collecting phase of the ‘Adapting Agriculture to Climate Change’ project was, to the best of our knowledge, the most comprehensive crop wild relatives (CWR) collecting and conservation mission to-date and provides priceless genetic diversity for ongoing and future crop breeding efforts. The seed collecting started in 2013 and was concluded in 2019, it was carried out in 22 countries in Africa, Asia, the Americas and Europe, involving CWR taxa of 28 different crop genepools. 3002 target seed accessions of 242 taxa were collected and are currently stored long-term in the countries of collection and, in most of the cases, backed up at the Millennium Seed Bank (UK). Considering also non-target species, 3854 seed accessions were collected. For the genepools of bambara groundnut (Vigna subterranea (L.) Verdc.), barley (Hordeum L.), grass pea (Lathyrus sativus L.), sorghum (Sorghum bicolor (L.) Moench), and wheat (Triticum L.), the collecting phase was highly successful in terms of diversity of both, species and populations. Despite the overall success of the project, in our analysis we discovered several issues that were encountered in the seed collecting. In particular, comparing the initial collecting targets with the seed accessions effectively collected it emerges that: (1) some important crop genepools were characterized by a low collecting success (e.g. banana/plantain (Musa L.), potato (Solanum tuberosum L.), rice (Oryza L.), (2) genepool 1 (the most important for breeding efforts) of some crop genepools was under-collected (e.g. eggplant (Solanum L.) and sorghum), (3) some important centres of plant biodiversity (especially the Indian Subcontinent) were underrepresented in the seed collecting. This analysis can guide further collecting missions in order to fill gaps in the long-term conservation of CWR of great importance for crop improvement.

     

Managing genebanks: seed base collection examined

An idea is advanced for the composition of seed base collections. Policy planning needs to be rethought as to the inventory of base collections. Curators often concentrate on the storage of unadapted cultivated materials while neglecting select improved cultivars and crop wild relatives. The fact that germ plasm customized to the farmer's immediate needs is present in low numbers in cold chambers suggests that base collection management operates at a relative distance from a market economy intent on food production. This attitude is antithetic to food security and raises the need for expert questioning on proper gene bank management. The view put forwarded here is that three major areas should head the inventory of base collections in genebanks, viz. landraces, improved breeding materials of multiple categories, and crop wild relatives. Base collections must ultimately serve society by becoming repositories for regulating and replenishing agricultural stocks, should stochastic catastrophe strike in the farm. The relentless pace of environmental degradation means that conservation per se is the top priority for crop wild relatives.     

Strategies and priorities in field collections for ex situ conservation: the case of the Israel Plant Gene Bank

The ex situ collection of the Israel Plant Gene Bank (IGB) aims to encompass the rich local flora and its genetic diversity with an emphasis on crop wild relatives. However, to properly establish a core collection, collection efforts must be prioritized and strategized. We previously classified local plant genetic resources into four priority groups that assisted in strategizing the collection activities. The following years of intensive collection activity yielded over 4200 banked accessions. However, these do not necessarily represent the distribution range of the target species for collection (TSC) and consequently, their genetic diversity. To best cover the latter, the collecting area was divided into botanical districts and the magnitude of the collection was determined according to prioritization group, e.g., a wild relative of an agricultural crop with a vast distribution range should be represented by a larger number of banked accessions than one with a smaller range. Continuous evaluation of specific needs shapes the collection scheme of the IGB to maximize collection efforts, better represent the presumed genetic diversity of TSC, and establish its core collection.     

Ethnobotanical investigation and diversity of Gbolo (Crassocephalum rubens (Juss. ex Jacq.) S. Moore and Crassocephalum crepidioides (Benth.) S. Moore), a traditional leafy vegetable under domestication in Benin

Thirty five villages randomly selected across ethnic and agro-ecological zones of Benin were surveyed to document the indigenous knowledge associated with the domestication (bringing into cultivation), production and utilization of vegetable Gbolo (Crassocephalum spp.). The study revealed the existence of different morphotypes (1–4 per village) corresponding to two botanical species (Crassocephalum rubens (Juss. ex Jacq.) S. Moore) and (Crassocephalum crepidioides (Benth.) S. Moore) found unequally distributed throughout the country. The domestication (bringing into cultivation from the wild) of Gbolo was started in many villages and with some tribes in southern Benin, the vegetable is already being produced in sole cropping for commercial purposes. Regular consumption (49.90 % of responses) and scarcity (20.30 % of responses) were the two main reasons attributed by the interviewees for domestication of the vegetable. The cultural practices recorded were of five categories. The commonest cropping system found was mixed or inter-row cropping (92.31 % of producers) with either vegetable crops (53.85 % of producers) or non-vegetable crops (38.46 % of users). Sauce prepared with either fresh or dried leaves was the main type of preparation of Gbolo and the vegetable was reported to possess special nutritional and medicinal values. For further promotion, important researches directions are suggested.     

The original features of rice (Oryza sativa L.) genetic diversity and the importance of within-variety diversity in the highlands of Madagascar build a strong case for in situ conservation

In situ conservation of crop genetic resources is widely recommended but, as yet, no methods have been developed to rank the genetic entities to preserve and the social organisations to involve. The highlands of Madagascar have been identified as a key site for rice, Oryza sativa, genetic diversity. To define conservation strategies, we performed multidisciplinary analysis of rice genetic diversity and factors shaping its distribution in the target region. Along with the indica and japonica rice subspecies of O. sativa, we confirmed the presence of an atypical rice group with a preferential habitat of 1,250–1,750 m. Spatial distribution of genetic diversity was uneven. The most determining factor of this unevenness was the altitude authorising or not the presence of different rice cropping systems and the associated types of varieties. Village and individual farmer’s wealth also had a determining role on the amount of rice diversity they hosted. While molecular variance between villages in a given interval of altitude represented 16 % of the total variance, within-village variance represented more than 75 % of the total, and within-farm variance 70 % of within-village variance. This hierarchical distribution of molecular variance suggests that a small number of samples per scale (altitude interval, village and farm) could allow to capture most of the genetic diversity observed. However, within-variety diversity was also important making ex situ conservation strategies impractical and costly. Implications of the within-variety diversity are discussed in terms of adaptive advantages, evolutionary processes, and need for in situ conservation.     

A prioritised inventory of crop wild relatives and wild harvested plants of Tunisia

Genetic Resources and Crop Evolution - An inventory of crop wild relatives (CWR) and wild harvested plants (WHP) occurring in Tunisia, based on the integration of the last available floristic...     

Selecting in situ conservation sites for grape genetic resources in the USA

Previously, there has not been any in situ conservation sites for crop germplasm within the United States Department of Agriculture (USDA), Agricultural Research Service (ARS), National Plant Germplasm System (NPGS). Using morphologic and molecular (SSR markers) techniques, we assessed the genetic variation present in populations of rock grape (Vitis rupestris Scheele), a native American grape species, throughout its range. We identified seven in situ conservation sites for rock grape using a strategy based on morphologic and molecular data, taxonomic information, population size and integrity, and landholder commitment. In collaboration with federal and state landholding agencies, we have established the first NPGS in situ conservation sites for American wild relatives of a crop.     

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

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

Population genetic structure of in situ wild Sorghum bicolor in its Ethiopian center of origin based on SSR markers

In situ population studies of wild relatives of crops are crucial for the conservation of plant genetic resources, especially in regions with high genetic diversity and a risk of local extinction. Ethiopia is the center of origin for sorghum, yet little is known about the genetic structure of extant wild populations. Using 9 Simple Sequence Repeat loci, we characterized 19 wild populations from five regions, 8 local cultivar populations from three regions, and 10 wild sorghum accessions from several African countries. To our knowledge, this is the most comprehensive study to date of in situ wild sorghum populations in Africa. Genetic diversity corrected for sample size was significantly greater in the wild populations in situ than in local cultivars or the accessions. Approximately 41 % of the genetic variation in the wild plants was partitioned among populations, indicating a high degree of differentiation and potential value for germplasm conservation, and the average number of migrants (N_m) per generation was 0.43. Cluster analyses showed that some wild populations were grouped by geographic region, whereas others were not, presumably due to long-distance seed movement. Four wild populations from disjunct regions formed a unique cluster with an Ethiopian accession of subsp. drummondii and probably represent a weedy race. STRUCTURE and other analyses detected evidence for crop-wild hybridization, consistent with previous molecular marker studies in Kenya, Mali, and Cameroon. In summary, in situ wild sorghum populations in Ethiopia harbor substantial genetic diversity and differentiation, despite their close proximity to conspecific cultivars in this crop/wild/weedy complex.