Ex Situ Conservation Priorities for the Wild Relatives of Potato (Solanum L. Section Petota)

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.     

A global approach to crop wild relative conservation: securing the gene pool for food and agriculture

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.     

The impact of climate change on the future distribution of priority crop wild relatives in Indonesia and implications for conservation planning

The analysis of climate change impact is essential to include in conservation planning of crop wild relatives (CWR) to provide the guideline for adequate long-term protection under unpredictable future environmental conditions. These resources play an important role in sustaining the future of food security, but the evidence shows that they are threatened by climate change. The current analyses show that five taxa were predicted to have contraction of more than 30 % of their current ranges: Artocarpus sepicanus (based on RCP 4.5 in both no dispersal and unlimited dispersal scenario and RCP 8.5 in no dispersal scenario by 2050), Ficus oleifolia (RCP 4.5 5 in both no dispersal and unlimited dispersal scenario by 2080), Cocos nucifera and Dioscorea alata (RCP 8.5 in both no dispersal and unlimited dispersal scenario by 2050), and Ficus chartacea (RCP 8.5 in both no dispersal and unlimited dispersal scenario by 2050 and 2080). It shows that the climate change impact is species-specific. Representative Concentration Pathways (RCP) of greenhouse gas (GHG) emission and dispersal scenarios influence the prediction models, and the actual future distribution range of species falls in between those scenarios. Climate refugia, holdout populations, and non-analogue community assemblages were identified based on the Protected Areas (PAs) network. PAs capacity is considered an important element in implementing a conservation strategy for the priority CWR. In areas where PAs are isolated and have less possibility to build corridors to connect each other, such as in Java, unlimited dispersal scenarios are unlikely to be achieved and assisted dispersal is suggested. The holdout populations should be the priority target for the ex situ collection. Therefore, by considering the climate refugia, PAs capacity and holdout populations, the goal of keeping high genetic variations for the long-term conservation of CWR in Indonesia can be achieved.     

Gap analyses of priority wild relatives of food crop in current ex situ and in situ conservation in Indonesia

Conservation programmes are always limited by available resources. Careful planning is therefore required to increase the efficiency of conservation and gap analysis can be used for this purpose. This method was used to assess the representativeness of current ex situ and in situ conservation actions of 234 priority crop wild relatives (CWR) in Indonesia. This analysis also included species distribution modelling, the creation of an ecogeographical land characterization map, and a complementarity analysis to identify priorities area for in situ conservation and for further collecting of ex situ conservation programmes. The results show that both current ex situ and in situ conservation actions are insufficient. Sixty-six percent of priority CWRs have no recorded ex situ collections. Eighty CWRs with ex situ collections are still under-represented in the national genebanks and 65 CWRs have no presence records within the existing protected area network although 60 are predicted to exist in several protected areas according to their potential distribution models. The complementarity analysis shows that a minimum of 61 complementary grid areas (complementary based on grid cells) are required to conserve all priority taxa and 40 complementary protected areas (complementary based on existing protected areas) are required to conserve those with known populations within the existing in situ protected area network. The top ten of complementary protected areas are proposed as the initial areas for the development of CWR genetic reserves network in Indonesia. It is recommended to enhanced coordination between ex situ and in situ conservation stakeholders for sustaining the long term conservation of CWR in Indonesia. Implementation of the research recommendations will provide for the first time an effective conservation planning of Indonesia’s CWR diversity and will significantly enhance the country’s food and nutritional security.

     

Endemic wild potato (Solanum spp.) biodiversity status in Bolivia: Reasons for conservation concerns

Crop wild relatives possess important traits, therefore ex situ and in situ conservation efforts are essential to maintain sufficient options for crop improvement. Bolivia is a centre of wild relative diversity for several crops, among them potato, which is an important staple worldwide and the principal food crop in this country. Despite their relevance for plant breeding, limited knowledge exists about their in situ conservation status. We used Geographic Information Systems (GIS) and distribution modelling with the software Maxent to better understand geographic patterns of endemic wild potato diversity in Bolivia. In combination with threat layers, we assessed the conservation status of all endemic species, 21 in total. We prioritised areas for in situ conservation by using complementary reserve selection and excluded 25% of the most-threatened collection sites because costs to implement conservation measures at those locations may be too high compared to other areas. Some 70% (15 of 21 species) has a preliminary vulnerable status or worse according to IUCN red list distribution criteria. Our results show that four of these species would require special conservation attention because they were only observed in <15 locations and are highly threatened by human accessibility, fires and livestock pressure. Although highest species richness occurs in south-central Bolivia, in the departments Santa Cruz and Chuquisaca, the first priority area for in situ conservation according to our reserve selection exercise is central Bolivia, Cochabamba; this area is less threatened than the potato wild relatives’ hotspot in south-central Bolivia. Only seven of the 21 species were observed in protected areas. To improve coverage of potato wild relatives’ distribution by protected areas, we recommend starting inventories in parks and reserves with high modelled diversity. Finally, to improve ex situ conservation, we targeted areas for germplasm collection of species with <5 accessions conserved in genebanks.     

Conserving Plants in Gene Banks and Nature: Investigating Complementarity with Trifolium thompsonii Morton

A standard conservation strategy for plant genetic resources integrates in situ (on-farm or wild) and ex situ (gene or field bank) approaches. Gene bank managers collect ex situ accessions that represent a comprehensive snap shot of the genetic diversity of in situ populations at a given time and place. Although simple in theory, achieving complementary in situ and ex situ holdings is challenging. Using Trifolium thompsonii as a model insect-pollinated herbaceous perennial species, we used AFLP markers to compare genetic diversity and structure of ex situ accessions collected at two time periods (1995, 2004) from four locations, with their corresponding in situ populations sampled in 2009. Our goal was to assess the complementarity of the two approaches. We examined how gene flow, selection and genetic drift contributed to population change. Across locations, we found no difference in diversity between ex situ and in situ samples. One population showed a decline in genetic diversity over the 15 years studied. Population genetic differentiation among the four locations was significant, but weak. Association tests suggested infrequent, long distance gene flow. Selection and drift occurred, but differences due to spatial effects were three times as strong as differences attributed to temporal effects, and suggested recollection efforts could occur at intervals greater than fifteen years. An effective collecting strategy for insect pollinated herbaceous perennial species was to sample >150 plants, equalize maternal contribution, and sample along random transects with sufficient space between plants to minimize intrafamilial sampling. Quantifying genetic change between ex situ and in situ accessions allows genetic resource managers to validate ex situ collecting and maintenance protocols, develop appropriate recollection intervals, and provide an early detection mechanism for identifying problematic conditions that can be addressed to prevent further decline in vulnerable in situ populations.     

Gap analyses to support ex situ conservation of genetic diversity in Magnolia, a flagship group

Worldwide about one third of all plant species is estimated to be threatened with extinction. Plants are generally under-represented in conservation. However, the global strategy for plant conservation (GSPC) sets forth 16 targets to halt the current and continuing loss of plant diversity within a framework for actions at global, regional, national and local levels. Target 8 of the GSPC directs that at least 75 % of threatened plant species be present in ex situ collections by 2020, but this target is far from being met. By analyzing where gaps in ex situ collections and research exist relative to diversity hotspots of threatened species, it is possible to identify and prioritize action. We undertake a gap analysis of ex situ collection needs in the genus Magnolia, a relatively well-known and valuable genus. Results indicate three main areas of biodiversity (China, Vietnam and Colombia) for the endangered Magnolia taxa. The present paper provides a critical overview of recent conservation activities carried out in the genus Magnolia throughout the world, focusing on genetic diversity analyses of the species.     

Population and genetic status of a critically endangered species in Korea, Euchresta japonica (Leguminosae), and their implications for conservation

The conservation status of Euchresta japonica Hook. f. ex Regel in Korea was investigated, with an emphasis on its genetic diversity. From field surveys, we obtained the only locality record for a wild population in Korea, which contained eight individuals. Genotyping was performed using nine microsatellite markers for all 20 remaining individuals, including those in ex situ collections. Among nine microsatellite loci that amplified within this group, five showed polymorphism with low hererozygosities, and a total of 12 multilocus genotypes were detected. Wild-specific alleles were detected in two individuals, and ex situ-specific alleles were detected in six individuals. Five individuals proved to have individual-specific alleles. The Korean population was also distinguished from the previously reported Japanese population by different alleles and higher diversity. To conserve this species more effectively in Korea, we recommend the following: (1) fencing the remaining wild population; (2) no relocation of wild individuals, as nine ex situ plants are already available; (3) complete ex situ conservation of all genetic diversity via clonal propagation of wild individuals; and (4) continuous protection and monitoring of the wild population.     

Is It Still Necessary to Continue to Collect Crop Genetic Resources in the Mediterranean Area? A Case Study in Catalonia

Crop genetic resources have been extensively collected in Europe in the last century, creating large, publicly available ex situ collections. While this huge genetic diversity is often underutilized, in recent decades, several initiatives have emerged at the local level to collect germplasm cultivated on farm. Uncoordinated actors often carry out these collecting missions without considering previously collected data. To explore whether new collecting missions are likely to be worthwhile, we studied the crop genetic resources conservation network in Catalonia by analyzing the passport data and geographical distribution of germplasm stored in seed banks. Moreover, to determine whether this germplasm was representative of the diversity cultivated on farm, we performed new collecting missions in four randomly selected areas in the European Union’s Natura 2000 network and compared the results with the ex situ databases. Seed banks currently hold a large germplasm collection (2931 accessions), although most materials are conserved in private collections without regulated systems for seed regeneration and are not present as duplicates in the National Inventory. One important shortcoming of the ex situ network is that the germplasm conserved ex situ shows a low geographical coverage, representing only 35.3% of the municipalities in Catalonia. Our new missions allowed us to collect 234 accessions, mostly tomatoes (17.5%) and beans (16.2%). The ecological indicators’ richness (both at species (S) and variety (V) levels), total abundance (A), and the Shannon-Weaver diversity index calculated at species (H2, considering the different accessions of each variety as a single population) and variety levels (H3, considering the intra-varietal genetic diversity) were higher in the newly collected germplasm than in the ex situ collections, suggesting that seed banks do not accurately represent the genetic diversity still cultivated on farm. Moreover, some important landraces from each area were absent or underrepresented in the ex situ collections. Thus, it is necessary to continue to devote efforts to collecting germplasm; better organization between actors and targeting specific species/varieties can increase the efficiency of new collecting missions. As a conclusion, we propose different criteria to guide new missions and to improve the network’s conservation activities.     

Importance of <Emphasis Type="Italic">in vitro</Emphasis> technology to future conservation programmes worldwide

The latest IUCN statistics show that of over 12,000 plant species, 70% are threatened, 19% are critically endangered and 28 species are extinct in the wild. Target 8 of the Global Strategy for Plant Conservation (GSPC) highlights the importance of ex situ conservation of critically endangered plants. Long-term germplasm storage for species with recalcitrant seeds needs alternative measures. In vitro methods complement seed banking and other ex situ measures and are vital for long-term conservation. Conservation Biotechnology at RBG Kew is currently working on a number of rare and threatened recalcitrant species from biodiversity-rich areas of the world to develop good quality in vitro propagules for cryopreservation, recovery and restoration projects. The importance of successful in vitro propagation methods, transplantation technologies, cryopreservation and international networking for the integrated conservation of these species are discussed in detail.     

Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation

Inter-specific hybridization may be especially detrimental when one species is extremely rare and the other is abundant owing to the potential for genetic swamping. The Cuban crocodile (Crocodylus rhombifer) is a critically endangered island endemic largely restricted to Zapata Swamp, where it is sympatric with the widespread American crocodile (C. acutus). An on-island, C. rhombifer captive breeding program is underway with the goals of maintaining taxonomic integrity and providing a source of individuals for reintroduction, but its conservation value is limited by lack of genetic information. Here we collected mtDNA haplotypic and nuclear genotypic data from wild and captive C. rhombifer and C. acutus in Cuba to: (1) investigate the degree of inter-specific hybridization in natural (in situ) and captive (ex situ) populations; (2) quantify the extent, distribution and in situ representation of genetic variation ex situ; and (3) reconstruct founder relatedness to inform management. We found high levels of hybridization in the wild (49.1%) and captivity (16.1%), and additional evidence for a cryptic lineage of C. acutus in the Antilles. We detected marginally higher observed heterozygosity and allelic diversity ex situ relative to the wild population, with captive C. rhombifer exhibiting over twice the frequency of private alleles. Although mean relatedness was high in captivity, we identified 37 genetically important individuals that possessed individual mean kinship (MK) values lower than the population MK. Overall, these results will guide long-term conservation management of Cuban crocodiles for maintaining the genetic integrity and viability of this species of high global conservation value.     

Current status and conservation of Pistacia germplasm

The genetic erosion of Pistacia germplasm has been highlighted in many reports. In order to emphasize this and to focus more attention on this subject, national and international (especially IPGRI and IFAR) institutions have initiated projects proposing to characterize, collect and conserve Pistacia germplasm. Therefore, this paper reviews recent research concerning conventional (in situ and ex situ) and unconventional biotechnological conservation strategies applied to the preservation of Pistacia germplasm. As regards conventional conservation, the majority of germplasm collections of Pistacia species are preserved on farms (in situ) and in seed and field genebanks (ex situ), as well as in the wild, where they are vulnerable to unexpected weather conditions and/or diseases. Hence, complementary successful unconventional in vitro methods (organogenesis, somatic embryogenesis and micrografting) and slow-growth storage conditions for medium-term preservation of Pistacia are presented together with the morphological and molecular studies carried out for the characterization of its species in this review. Moreover, special attention is additionally focused on cryopreservation (dehydration- and vitrification-based one-step freezing techniques) for the long-term preservation of Pistacia species. Possible basic principles concerning the establishment of a cryobank for the successful conservation of Pistacia germplasm are also discussed.     

Projecting the effects of climate change on the distribution of maize races and their wild relatives in Mexico

Climate change is expected to be a significant threat to biodiversity, including crop diversity at centers of origin and diversification. As a way to avoid food scarcity in the future, it is important to have a better understanding of the possible impacts of climate change on crops. We evaluated these impacts on maize, one of the most important crops worldwide, and its wild relatives Tripsacum and Teocintes. Maize is the staple crop in Mexico and Mesoamerica, and there are currently about 59 described races in Mexico, which is considered its center of origin . In this study, we modeled the distribution of maize races and its wild relatives in Mexico for the present and for two time periods in the future (2030 and 2050), to identify the potentially most vulnerable taxa and geographic regions in the face of climate change. Bioclimatic distribution of crops has seldom been modeled, probably because social and cultural factors play an important role on crop suitability. Nonetheless, rainfall and temperature still represent a major influence on crop distribution pattern, particularly in rainfed crop systems under traditional agrotechnology. Such is the case of Mexican maize races and consequently, climate change impacts can be expected. Our findings generally show significant reductions of potential distribution areas by 2030 and 2050 in most cases. However, future projections of each race show contrasting responses to climatic scenarios. Several evaluated races show new potential distribution areas in the future, suggesting that proper management may favor diversity conservation. Modeled distributions of Tripsacum species and Teocintes indicate more severe impacts compared with maize races. Our projections lead to in situ and ex situ conservation recommended actions to guarantee the preservation of the genetic diversity of Mexican maize.     

Evolutionary and Biogeographic Insights on the Macaronesian Beta-Patellifolia Species (Amaranthaceae) from a Time-Scaled Molecular Phylogeny

The Western Mediterranean Region and Macaronesian Islands are one of the top biodiversity hotspots of Europe, containing a significant native genetic diversity of global value among the Crop Wild Relatives (CWR). Sugar beet is the primary crop of the genus Beta (subfamily Betoideae, Amaranthaceae) and despite the great economic importance of this genus, and of the close relative Patellifolia species, a reconstruction of their evolutionary history is still lacking. We analyzed nrDNA (ITS) and cpDNA gene (matK, trnH-psbA, trnL intron, rbcL) sequences to: (i) investigate the phylogenetic relationships within the Betoideae subfamily, and (ii) elucidate the historical biogeography of wild beet species in the Western Mediterranean Region, including the Macaronesian Islands. The results support the Betoideae as a monophyletic group (excluding the Acroglochin genus) and provide a detailed inference of relationships within this subfamily, revealing: (i) a deep genetic differentiation between Beta and Patellifolia species, which may have occurred in Late Oligocene; and (ii) the occurrence of a West-East genetic divergence within Beta, indicating that the Mediterranean species probably differentiated by the end of the Miocene. This was interpreted as a signature of species radiation induced by dramatic habitat changes during the Messinian Salinity Crisis (MSC, 5.96–5.33 Mya). Moreover, colonization events during the Pleistocene also played a role in shaping the current diversity patterns among and within the Macaronesian Islands. The origin and number of these events could not be revealed due to insufficient phylogenetic resolution, suggesting that the diversification was quite recent in these archipelagos, and unravelling potential complex biogeographic patterns with hybridization and gene flow playing an important role. Finally, three evolutionary lineages were identified corresponding to major gene pools of sugar beet wild relatives, which provide useful information for establishing in situ and ex situ conservation priorities in the hotspot area of the Macaronesian Islands.     

Conservation of medicinal plants of Western Ghats,India and its sustainable utilization through <Emphasis Type="Italic">in vitro</Emphasis> technology

Climate change, alien species, and use of land for intensive farming and development are causing severe threat to the plant genetic diversity worldwide. Hence, conservation of biodiversity is considered fundamental and also provides the livelihoods to millions of people worldwide. Medicinal plants play a key role in the treatment of a number of diseases, and they are only the source of medicine for majority of people in the developing world. The tropical regions of the world supply the bulk of current global demand for “natural medicine,” albeit with increasing threat to populations in the world and its genetic diversity. India is a major center of origin and diversity of crop and medicinal plants. India poses out 20,000 species of higher plants, one third of it being endemic and 500 species are categorized to have medicinal value. The Western Ghats is one of the major repositories of medicinal plants. It harbors around 4,000 species of higher plants of which 450 species are threatened. Currently, the number of species added to the red list category in this region is increasing, and the valuable genetic resources are being lost at a rapid rate. Demand for medicinal plants is increasing, and this leads to unscrupulous collection from the wild and adulteration of supplies. Providing high-quality planting material for sustainable use and thereby saving the genetic diversity of plants in the wild is important. During the last 25 years of intensive research, Tropical Botanic Garden and Research Institute has developed in vitro protocol for rapid regeneration and establishment of about 40 medicinally important rare and threatened plants of Western Ghats. In situ conservation alone would not be effective in safeguarding these important species. Thus, utilizing the biotechnoligical approach to complement ex situ conservation program is becoming vital. Propagating biotechnology tools in plant conservation program is a prerequisite to succeed in sustainable use and to complement the existing ex situ measures. In addition to propagation, storage of these valuable genetic resources is equally important. In vitro slow growth of 35 species and cryopreservation using embryo/meristem/seed in 20 different species of rare medicinal plants of this region is accomplished. Plants developed in vitro of ten medicinal plants, which have restricted distribution, were reintroduced in the natural habitat as well.     

The study of genetic diversity patterns of Coffea commersoniana, an endangered coffee species from Madagascar: a model for conservation of other littoral forest species

Madagascar has 59 described species of Coffea, of which 42 are listed as critically endangered, endangered, or vulnerable by the criteria of the Red List Category system of the World Conservation Union (IUCN). The littoral forest of Madagascar is a distinctive type of humid evergreen forest restricted to unconsolidated sand located within a few kilometers of the Indian Ocean, now persisting only as small fragments with ca. 10 % of its original range remaining. In an attempt to understand the genetic diversity of Madagascan coffee species, we studied ex situ and in situ populations of Coffea commersoniana, an endemic species of the littoral forests of southeastern Madagascar and soon to be impacted by mining activities in that region. The in situ populations studied showed higher genetic diversity than the ex situ population. The genetic partitioning among the two in situ populations of C. commersoniana was high enough to necessitate keeping the two populations separate for restoration purposes. Based on these findings, recommendations for conservation management (in situ and ex situ) are made.     

Genetic diversity of two endemic and endangered Plantago species

Plantago algarbiensis and Plantago almogravensis are two endangered and endemic species from Portugal. Due to the rarity and endangered nature of these species as well as the lack of molecular data, their genetic variation was evaluated using ISSR and RAPD markers. P. algarbiensis species showed higher genetic variability (73.9% of polymorphism) than P. almogravensis (61.2%). The two species revealed a high level of genetic diversity, with a Nei's genetic diversity of 0.1965 and 0.2309 and a Shannon's diversity index of 0.2975 and 0.3520, for P. almogravensis and P. algarbiensis, respectively. A low level of genetic differentiation was observed (Gst = 0.1873) among the species. However, the cluster and PCA analyses, based on genetic similarity, revealed two main, clearly separate clusters, which directly corresponded to the plants isolated from each species. In situ and ex situ measures should be applied in order to preserve both species but, based on these results, P. almogravensis population should be a priority for conservation.