Seasonally dry tropical forests are distributed across Latin America and the Caribbean and are highly threatened, with less than 10% of their original extent remaining in many countries. Using 835 inventories covering 4660 species of woody plants, we show marked floristic turnover among inventories and regions, which may be higher than in other neotropical biomes, such as savanna. Such high floristic turnover indicates that numerous conservation areas across many countries will be needed to protect the full diversity of tropical dry forests. Our results provide a scientific framework within which national decision-makers can contextualize the floristic significance of their dry forest at a regional and continental scale. N eotropical seasonally dry forest (dry forest) is a biome with a wide and fragmented distribution, found from Mexico to Argentina and throughout the Caribbean (1, 2) ( Fig. 1). It is one of the most threatened tropical forests in the world (3), with less than 10% of its original extent remaining in many countries (4).Following other authors (5, 6), we define dry forest as having a closed canopy, distinguishing it from more open, grass-rich savanna. It occurs on fertile soils where the rainfall is less thañ 1800 mm per year, with a period of 3 to 6 months receiving less than 100 mm per month (5-7), during which the vegetation is mostly deciduous. Seasonally dry areas, especially in Peru and Mexico, were home to pre-Columbian civilizations, so human interaction with dry forest has a long history (8). The climates and fertile soils of dry forest regions have led to higher human population densities and an increasing demand for energy and land, enhancing degradation (9). More recently, destruction of dry forest has been accelerated by intensive cultivation of crops, such as sugar cane, rice and soy, or by conversion to pasture for cattle.Dry forest is in a critical state because so little of it is intact, and of the remnant areas, little is protected (3). For example, only 1.2% of the total Caatinga region of dry forest in Brazil is fully protected compared with 9.9% of the Brazilian Amazon (10). Conservation actions are urgently needed to protect dry forest's unique biodiversity-many plant species and even genera are restricted to it and reflect an evolutionary history confined to this biome (1).We evaluate the floristic relationships of the disjunct areas of neotropical dry forest and highlight those that contain the highest diversity and endemism of woody plant species. We also explore woody plant species turnover across geographic space among dry forests. Our results provide a framework to allow the conservation significance of each separate major region of dry forest to be assessed at a continental scale. Our analyses are based on a subset of a data set of 1602 inventories made in dry forest and related semi-deciduous forests from Mexico and the Caribbean to Argentina and Paraguay that covers 6958 woody species, which has been compiled by the Latin American and Caribbean Seasonally Dry Tropica...

ABSTRACT. Mussels are one of the most cultivated and commercialized bivalves worldwide and in southern Chile its culture represent an important economic activity. The species identification within the Mytilus genera, by morphological features, is unreliable, so we used a polymorphism RFLP in the gene encoding the polyphenolic adhesive protein as a species-specific genetic marker to describe Mytilus species diversity in southern Chile, and evaluate possible applications in traceability, food quality and safety. Using Me 15-16 marker most mussels were M. chilensis, finding no other pure individuals; however, putative hybrids of M. chilensis x M. trossulus and M. chilensis x M. galloprovincialis were detected. There was no evidence of M. edulis. The presence of the M. trossulus allele, faraway from its distribution area, demands further analysis with different genetic markers to allow a better understanding of its origin. In addition, the correspondence between markers that distinguishes northern from southern hemisphere M. galloprovincialis, with those who discriminates between M. chilensis and M. galloprovincialis would contribute to the taxonomic status of Chilean blue mussels. In Chile, the genetic composition of Mytilus indicates that geographical origin of mussels and its traceability cannot be established merely from the identification of the species. The use of other markers would be required. Keywords: Mytilus, mussels, genetic identification, Me 15-16, PCR-RFLP, southern Chile. Composición genética de especies de

The narrow genetic base of commercial arabica resulting from intensive selection for quality during domestication and self-pollination has been well documented, raising the need for new diverse germplasm sources. Beans of 232 diverse arabica coffee accessions originating from 27 countries were harvested from the germplasm collection at CATIE, Costa Rica. Substantial variation was observed for bean morphology including 100 bean weight, bean length, width, thickness and bulk density. Non-volatiles including caffeine and trigonelline were analysed and showed larger variation in range than has previously been reported. Results of targeted analysis of 18 volatiles from 35 accessions also showed significant variation, with coefficients of variation from 140% for 4-vinylguaiacol to 62% for geraniol. There were strong correlations between some volatile compounds, suggesting that representative volatiles used in selection would save analytical costs. However, no strong correlation was found between bean morphology and the levels of non-volatile or volatile compounds, implying that it is difficult to select for low or high composition of these compounds based on bean physical characteristics. Utilizing the large variation observed for bean morphology and biochemical traits, it should be possible to select for desirable combinations of traits in arabica coffee breeding.

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Association analysis was performed at the whole genome level to identify loci affecting the caffeine and trigonelline content of Coffea arabica beans. DNA extracted from extreme phenotypes was bulked (high and low caffeine, and high and low trigonelline) based on biochemical analysis of the germplasm collection. Sequencing and mapping using the combined reference genomes of C. canephora and C. eugenioides (CC and CE) identified 1351 non-synonymous SNPs that distinguished the lowand high-caffeine bulks. Gene annotation analysis with Blast2GO revealed that these SNPs corresponding to 908 genes with 56 unique KEGG pathways and 49 unique enzymes. Based on KEGG pathway-based analysis, 40 caffeine-associated SNPs were discovered, among which nine SNPs were tightly associated with genes encoding enzymes involved in the conversion of substrates (i.e. SAM, xanthine and IMP) which participate in the caffeine biosynthesic pathways. Likewise, 1060 nonsynonymous SNPs were found to distinguish the low-and high-trigonelline bulks. They were associated with 719 genes involved in 61 unique KEGG pathways and 51 unique enzymes. The KEGG pathway-based analysis revealed 24 trigonelline-associated SNPs tightly linked to genes encoding enzymes involved in the conversion of substrates (i.e. SAM, L-tryptophan) which participate in the trigonelline biosynthesis pathways. These SNPs could be useful targets for further functional validation and subsequent application in arabica quality breeding. Keywords Caffeine. Trigonelline. Association mapping. Extreme phenotypes. TAVs Key message Forty caffeine-associated SNPs and 24 trigonellineassociated SNPs tightly linked to genes encoding enzymes involved in the conversion of substrates which participate in the caffeine and trigonelline biosynthesic pathways were Communicated by V. Decroocq