The tope shark (Galeorhinus galeus Linnaeus, 1758) is a temperate, coastal hound shark found in the Atlantic and Indo-Pacific oceans. In this study, the population structure of Galeorhinus galeus was determined across the entire Southern Hemisphere, where the species is heavily targeted by commercial fisheries, as well as locally, along the South African coastline. Analysis was conducted on a total of 185 samples using 19 microsatellite markers and a 671 bp fragment of the NADH dehydrogenase subunit 2 (ND2) gene. Across the Southern Hemisphere, three geographically distinct clades were recovered, including one from South America (Argentina, Chile), one from Africa (all the South African collections) and an Australia-New Zealand clade. Nuclear data revealed significant population subdivisions (FST = 0.192 to 0.376, p<0.05) indicating limited gene flow for tope sharks across ocean basins. Marked population connectivity was however evident across the Indian Ocean based on Bayesian clustering analysis. More locally in South Africa, F-statistics and multivariate analysis supported moderate to high gene flow across the Atlantic/Indian Ocean boundary (FST = 0.035 to 0.044, p<0.05), with exception of samples from Struisbaai and Port Elizabeth which differed significantly from the rest. Discriminant and Bayesian clustering analysis indicated admixture in all sampling populations, decreasing from west to east, corroborating possible restriction to gene flow across regional oceanographic barriers. Mitochondrial sequence data recovered seven haplotypes (h = 0.216, π = 0.001) for South Africa, with one major haplotype shared by 87% of the individuals and at least one private haplotype for each sampling location except Port Elizabeth. As with many other coastal shark species with cosmopolitan distribution, this study confirms the lack of both historical dispersal and inter-oceanic gene flow while also implicating contemporary factors such as oceanic currents and thermal fronts to drive local genetic structure of G. galeus on a smaller spatial scale.

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BACKGROUND:The recently developed Robusta coffee wilt disease resistant (CWD-r) varieties in Uganda outperform the local landraces, both in yield and resilience. However, their uptake has been slow due to limited information on their cup worth. This study profiled the cup worth of the five most commonly grown CWD-r across the Lake Victoria Crescent, Western Mid-altitude farmland and Central Wooded Savannah agro-ecologies. RESULTS: Significant correlations (P ≤ 0.05) were observed between soil nutrients and coffee bean size but this was not the case for biochemical and cup quality. The proportion of coffee beans retained on screen 15; minimum acceptable size through coffee commercial markets, ranged from 58.09% in Mukono to 92.49% in Mityana. Interestingly, the bean size of variety KR4 was hardly influenced by environmental variations, with portions of beans retained on screen 15 being relatively the same (80.30% Ibanda, 89.50% Mukono, 98.20% Mityana). Coffee cup quality for most of the varieties was scored as premium (70-79%) across three agro-ecologies, with the exception of KR4, which was scored specialty grade (≥80%). Coffee blends generated were used to make coffee products with specialty score (82.25%) and a distinctive aroma complex.CONCLUSION: In this study, blends of CWD-r resulted in superior cup scores (76-82%). These findings show that CWD-r varieties have a high cup worth with potential for wide adaptation in Uganda's Robusta coffee growing agro-ecologies. Most importantly, variety KR4 has resilience across three agro-ecologies with a consistent high bean size and superior cup quality, making it a candidate variety for the market and breeding.

Here, we report the first whole-genome assembly of a Fusarium xylarioides race pathogenic to robusta coffee in Uganda. It comprises 55,122,624 bases and 14,552 genes. Gene ontology analysis assigned 5,720 genes to biological processes, 4,545 genes to cellular components, and 6,021 genes to molecular function.

Coffea canephora has high but inadequately exploited genetic diversity. This diversity, if well exploited, can sustain coffee productivity amidst climate change effects. Drought and heat stress are major global threats to coffee productivity, quality, and tradable volumes. It is not well understood if there is a selectable variation for drought stress tolerance in Robusta coffee half-sibs as a result of watering deficit pre-exposure at the germination stage. Half-sib seeds from selected commercial clones (KR5, KR6, KR7) and a pipeline clone X1 were primed with deficit watering at two growth stages followed by recovery and later evaluated for tolerance to watering deficit stress in three different temperature environments by estimation of plant growth and wilt parameters. Overall, the KR7 family performed the best in terms of the number of individuals excelling for tolerance to deficit watering. In order of decreasing tolerance, the 10 most promising individuals for drought and heat tolerance were identified as: 14.KR7.2, 25.X1.1, 35.KR5.5, 36.KR5.6, 41.KR7.5, 46.KR6.4, 47.KR6.5, 291.X1.3, 318.X1.3, and 15.KR7.3. This is the first prospect into the potential of C. canephora half-sibs’ diversity as an unbound source of genetic variation for abiotic stress tolerance breeding.