Towards a practical threat assessment methodology for crop landraces

Crop landraces (LR), the traditional varieties of crops that have been maintained for millennia by repeated cycles of planting, harvesting, and selection, are genetically diverse compared to more modern varieties and provide one of the key components for crop improvement due to the ease of trait transfer within the crop species. However, LR diversity is increasingly threatened with genetic erosion and extinction by replacement with improved cultivars, lack of incentives for farmers to maintain traditional agricultural systems, and rising threats from climate change. Their active conservation is necessary to maintain this critical resource. However, as there are hundreds of thousands of LR and millions of LR populations for crops globally, active conservation is complex and resource-intensive. To assist in implementation, it is useful to be able to prioritise LR for conservation action and an obvious means of prioritisation is based on relative threat assessment. There have been several attempts to propose LR threat assessment methods, but none thus far has been widely accepted or applied. The aim of this paper is to present a novel, practical, standardised, and objective methodology for LR threat assessment derived from the widely applied IUCN Red Listing for wild species, involving the collation of time series information for LR population range, LR population trend, market, and farmer characteristics and LR context information. The collated information is compared to a set of threat criteria and an appropriate threat category is assigned to the LR when a threshold level is reached. The proposed methodology can be applied at national, regional, or global levels and any crop group.

A multi-taxon analysis of European Red Lists reveals major threats to biodiversity

Biodiversity loss is a major global challenge and minimizing extinction rates is the goal of several multilateral environmental agreements. Policy decisions require comprehensive, spatially explicit information on species' distributions and threats. We present an analysis of the conservation status of 14,669 European terrestrial, freshwater and marine species (ca. 10% of the continental fauna and flora), including all vertebrates and selected groups of invertebrates and plants. Our results reveal that 19% of European species are threatened with extinction, with higher extinction risks for plants (27%) and invertebrates (24%) compared to vertebrates (18%). These numbers exceed recent IPBES (Intergovernmental Platform on Biodiversity and Ecosystem Services) assumptions of extinction risk. Changes in agricultural practices and associated habitat loss, overharvesting, pollution and development are major threats to biodiversity. Maintaining and restoring sustainable land and water use practices is crucial to minimize future biodiversity declines.

Community-Level Incentive Mechanisms for the Conservation of Crop Wild Relatives: A Malawi Case Study

Despite being an increasingly important source of genes for crop breeding aimed at improving food security and climate change adaptation, crop wild relatives (CWRs) are globally threatened. A root cause of CWR conservation challenges is a lack of institutions and payment mechanisms by which the beneficiaries of CWR conservation services (such as breeders) could compensate those who can supply them. Given that CWR conservation generates important public good values, for the significant proportion of CWRs found outside of protected areas, there is a strong justification for the design of incentive mechanisms to support landowners whose management practices positively contribute to CWR conservation. This paper contributes to facilitating an improved understanding of the costs of in situ CWR conservation incentive mechanisms, based on a case study application of payments for agrobiodiversity conservation services across 13 community groups in three districts in Malawi. Results demonstrate a high willingness to participate in conservation activities, with average conservation tender bids per community group being a modest MWK 20,000 (USD 25) p.a. and covering 22 species of CWRs across 17 related crops. As such, there appears to be significant potential for community engagement in CWR conservation activities that is complementary to that required in protected areas and can be achieved at modest cost where appropriate incentive mechanisms can be implemented.

Maximizing the crop wild relative resources available to plant breeders for crop improvement

Crop breeders are currently facing the need to continue increasing crop production to feed the growing human population, while mitigating the negative impacts of climate change on agriculture. Taxonomic and genetic diversity, which includes taxa, genes and alleles that offer novel sources of resistance to pests, disease and abiotic factors that affect crop quality and quantity, are a key tool for crop breeders to address these challenges. Lack of access to this diversity is currently limiting crop improvement. This paper focuses on how the breeder's requirement for greater diversity may be met despite the continue challenges of growing human population, and the impacts of climate change. It is argued that gene pool diversity is largely concentrated in crop wild relatives (CWR) and their more active conservation, especially focusing on in situ conservation applications, will enable the breeding challenges to be met. Further, that the science of in situ conservation is only now coming of age but is sufficiently advanced to facilitate the establishment of integrated national, regional, and global in situ CWR conservation networks. For humankind to substantially benefit from the additional adaptive diversity made available through these collaborative networks for CWR in situ conservation for the first time, breeders need to be provided with the critical resources necessary to address the negative impacts of climate changes on food production—therefore promoting greater global food security.

Adapting Agriculture to Climate Change: A Synopsis of Coordinated National Crop Wild Relative Seed Collecting Programs across Five Continents

The Adapting Agriculture to Climate Change Project set out to improve the diversity, quantity, and accessibility of germplasm collections of crop wild relatives (CWR). Between 2013 and 2018, partners in 25 countries, heirs to the globetrotting legacy of Nikolai Vavilov, undertook seed collecting expeditions targeting CWR of 28 crops of global significance for agriculture. Here, we describe the implementation of the 25 national collecting programs and present the key results. A total of 4587 unique seed samples from at least 355 CWR taxa were collected, conserved ex situ, safety duplicated in national and international genebanks, and made available through the Multilateral System (MLS) of the International Treaty on Plant Genetic Resources for Food and Agriculture (Plant Treaty). Collections of CWR were made for all 28 targeted crops. Potato and eggplant were the most collected genepools, although the greatest number of primary genepool collections were made for rice. Overall, alfalfa, Bambara groundnut, grass pea and wheat were the genepools for which targets were best achieved. Several of the newly collected samples have already been used in pre-breeding programs to adapt crops to future challenges.

Climate change and national crop wild relative conservation planning

Climate change is likely to be one of the most important factors affecting our future food security. To mitigate negative impacts, we will require our crops to be more genetically diverse. Such diversity is available in crop wild relatives (CWRs), the wild taxa relatively closely related to crops and from which diverse traits can be transferred to the crop. Conservation of such genetic resources resides within the nation where they are found; therefore, national-level conservation recommendations are fundamental to global food security. We investigate the potential impact of climate change on CWR richness in Norway. The consequences of a 1.5 and 3.0 °C temperature rise were studied for the years 2030, 2050, 2070, 2080 and then compared to the present climate. The results indicate a pattern of shifting CWR richness from the south to the north, with increases in taxa turnover and in the numbers of threatened taxa. Recommendations for in situ and ex situ conservation actions over the short and long term for the priority CWRs in Norway are presented. The methods and recommendations developed here can be applied within other nations and at regional and global levels to improve the effectiveness of conservation actions and help ensure global food security.

Genome-wide association study of body mass index in 23 000 individuals with and without asthma

BACKGROUND

Both asthma and obesity are complex disorders that are influenced by environmental and genetic factors. Shared genetic factors between asthma and obesity have been proposed to partly explain epidemiological findings of co-morbidity between these conditions.

OBJECTIVE

To identify genetic variants that are associated with body mass index (BMI) in asthmatic children and adults, and to evaluate if there are differences between the genetics of BMI in asthmatics and healthy individuals.

METHODS

In total, 19 studies contributed with genome-wide analysis study (GWAS) data from more than 23 000 individuals with predominantly European descent, of whom 8165 are asthmatics.

RESULTS

We report associations between several DENND1B variants (P = 2.2 × 10(-7) for rs4915551) on chromosome 1q31 and BMI from a meta-analysis of GWAS data using 2691 asthmatic children (screening data). The top DENND1B single nucleotide polymorphisms(SNPs) were next evaluated in seven independent replication data sets comprising 2014 asthmatics, and rs4915551 was nominally replicated (P < 0.05) in two of the seven studies and of borderline significance in one (P = 0.059). However, strong evidence of effect heterogeneity was observed and overall, the association between rs4915551 and BMI was not significant in the total replication data set, P = 0.71. Using a random effects model, BMI was overall estimated to increase by 0.30 kg/m(2) (P = 0.01 for combined screening and replication data sets, N = 4705) per additional G allele of this DENND1BSNP. FTO was confirmed as an important gene for adult and childhood BMI regardless of asthma status.

CONCLUSIONS AND CLINICAL RELEVANCE

DENND1B was recently identified as an asthma susceptibility gene in a GWAS on children, and here, we find evidence that DENND1B variants may also be associated with BMI in asthmatic children. However, the association was overall not replicated in the independent data sets and the heterogeneous effect of DENND1B points to complex associations with the studied diseases that deserve further study.