Molecular markers were used to assess polymorphism between and within the genetic bases of coffee (i.e. Typica and Bourbon) spread from Yemen since the early 18th century that have given rise to most arabica cultivars grown world-wide. Eleven Coffea arabica accessions derived from the disseminated bases were evaluated by amplified fragment length polymorphism (AFLP) using 37 primer combinations and simple-sequence repeats (SSRs) produced by six microsatellites. Four cultivars growing in Yemen and 11 subspontaneous accessions collected in the primary centre of diversity of the species were included in the study in order to define their relationship with the accessions derived from the genetic bases of cultivars. One hundred and seven AFLP markers were used to calculate genetic distances and construct a dendrogram. The accessions derived from the disseminated bases were grouped separately, according to their genetic origin, and were distinguished from the subspontaneous accessions. The Yemen cultivars were classified with the Typica-derived accessions. Except for one AFLP marker, all AFLP and SSR markers present in the cultivated accessions were also detected in the subspontaneous accessions. Polymorphism among the subspontaneous accessions was much higher than among the cultivated accessions. It was very low within the genetic bases, confirming the historical documentation on their dissemination. The results enabled a discussion of the genetic diversity reductions that successively occurred during the dissemination of C. arabica from its primary centre of diversity.

No abstract

Mixed-charge pseudo-zwitterionic mesoporous silica nanoparticles with low-fouling and reduced cell uptake properties,

Cacao (Theobroma cacao L.) is an important economic crop in the Bolivian Amazon. Bolivian farmers both cultivate cacao, and extract fruits from wild stands in the Beni River region and in valleys of the Andes foothills. The germplasm group traditionally used is presently referred to as ''Cacao Nacional Boliviano'' (CNB). Using DNA fingerprinting technology based on microsatellite markers, we genotyped 164 Bolivian cacao accessions, including both cultivated and wild CNB accessions sampled from the Amazonian regions of La Paz and Beni, and compared their SSR profiles with 78 reference Forastero accessions from Amazonian cacao populations, including germplasm from the Ucayali region of Peru. Results of multivariate ordination and analysis of molecular variance show that CNB cacao has a unique genetic profile that is significantly different from the known cacao germplasm groups in South America. The results also show that cultivated CNB and wild CNB populations in the Beni River share a similar genetic profile, suggesting that the cultivated CNB is of indigenous origin in Bolivia. The level of genetic diversity, measured by allele richness and gene diversity in the Bolivian cacao, is moderately high, but was significantly lower than gene diversity in the other Amazonian cacao populations. Significant spatial genetic structure was detected in the wild CNB population, using analysis of autocorrelation (rc = 0.232; P \ 0.001) and Mantel tests (Rxy = 0.276; P \ 0.001). This finding is also highly valuable to support in situ conservation and sustainable use of CNB genetic diversity in Bolivia.

Coffee (Coffea spp.) is one of the world's most valuable agricultural export commodities produced by small‐scale farmers. Its germplasm, which holds useful traits for crop improvement, has traditionally been conserved in field genebanks, which presents many challenges for conservation. New techniques of in vitro and cryopreservation have been developed to improve the long‐term conservation of coffee. But a question remains as to whether these new techniques are more cost effective than field collections and more efficient at reducing genetic erosion. This study compared the costs of maintaining one of the world's largest coffee field collections with those of establishing a coffee cryo‐collection at the Centro Agronómico Tropical de Investigación y Enseñanza (CATIE) in Costa Rica. The results indicate that cryopreservation costs less (in perpetuity per accession) than conservation in field genebanks. A comparative analysis of the costs of both methods showed that the more accessions there are in cryopreservation storage, the lower the per‐accession cost. In addition to cost, the study examined the advantages of cryopreservation over field collection and showed that for species that are difficult to conserve using seeds, and that can only be conserved as live plants, cryopreservation may be the method of choice for long‐term conservation of genetic diversity.

The aim of this research was the genetic characterization of 218 accessions of Cucurbita moschata Duchesne, a squash, and its relationship with morphological characteristics of agronomic interest, which are part of the international collection conserved at Tropical Agricultural Research and Higher Education Center (CATIE), Costa Rica. The majority of the accessions came from Mexico and Central America; single genotypes from Curaao, Colombia, Peru and the Russian Federation were also included. The polymerase chain reaction (PCR) and single strand conformation polymorphism analysis (SSCP) were used for the analysis of the regions amplified with ITS1-ITS2 nuclear primers and tRNL-F chloroplast primers. Haplotypes were constructed according to band patterns in SSCP gels. Twenty-five haplotypes were found using the ITS1-ITS2 markers, and 24 haplotypes were found with the tRNL-F markers. Unique haplotypes were found with both markers. Two individuals of each tRNL-F haplotype were sequenced. The results indicated a high level of genetic diversity in CATIE squash collection. Using ITS1-ITS2 primers, it was found that the number of haplotypes was independent of the geographical source of the accession, and haplotypes were distributed randomly throughout the study area. Mexico had the highest values of total heterozygosity (HE), genetic diversity (H) and Shannon index (I) while Panama showed the lowest values. Sequences obtained from tRNL-F intergenic marker showed the highest diversity index values were present in the group of additional sequences and Mexico, and lower values were observed for Nicaragua, Guatemala and Panama. PCoA based on morphological data showed three groups and by ANOSIM (R) all group differences were significant. Results obtained in this study suggest that high diversity is a characteristic of C. moschata from Mesoamerica.

A sound understanding of crop history can provide the basis for deriving novel genetic information through admixture mapping. We confirmed this, by using characterization data from an international collection of cocoa, collected 25 years ago, and from a contemporary plantation. We focus on the trees derived from three centuries of admixture between Meso-American Criollo and South American Forastero genomes. In both cacao sets of individuals, linkage disequilibrium extended over long genetic distances along chromosome regions, as expected in populations derived from recent admixture. Based on loose genome scans, genomic regions involved in useful traits were identified. Fifteen genomic regions involved in seed and fruit weight variation were highlighted. They correspond to ten previously identified QTLs and five novel ones. Admixture mapping can help to add value to genetic resources and thus, help to encourage investment in their conservation.

Understanding the processes that affect freshwater ecosystems at the watershed level is fundamental for the conservation and management of river otters. During 2 consecutive years, we surveyed the occurrence of the Southern river otter Lontra provocax and its main prey (crustaceans) in a watershed of 9900 km 2 in the Chilean temperate forest. We modeled predator and prey distributions with a variety of statistical techniques by relating a set of environmental predictors to species occurrence records. Otter and crustaceans were associated with areas of intermediate to low human disturbance with a mosaic of riparian vegetation densities, mainly at low altitudes. The singularity of the Andean Range, with a very marked elevation gradient and oligotrophic watercourses in the higher areas, created more vulnerable conditions for otter presence because prey abundances were limited in those areas. Human impacts affected otter populations at a landscape scale through the presence of main roads, as these were mostly located in lower parts of the watershed where otters have their primary habitat. These results point to the importance of land management and protection of low-elevation areas where otters still occur to ensure the long-term viability of its freshwater populations.