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Northern Viet Nam displays a remarkable diversity of wild bananas (Musa L.), including the species from which the majority of cultivated bananas derive. The taxonomy and exact distribution of these wild bananas are however not well known, limiting their conservation and use. In the present study, we describe the morphology, ecology, and phytogeography of the 6 Musa species that were collected between 2016 and 2019 in northern Viet Nam: Musa acuminata Colla, M. balbisiana Colla, M. itinerans Cheesman, M. haekkinenii N.S.Ly & Haev, M. lutea R.V.Valmayor, L.D.Danh and Hakkinen and M. paracoccinea A.Z.Liu and D.Z.Li:. Of these, M. itinerans was the species with the most widespread distribution range, occurring as large mats in various habitats between 136 and 1331 m, whereas M. acuminata was found between 136 and 989 m and M. balbisiana was between 108 and 981 m. Furthermore, M. lutea, M. paracoccinea and M. haekkinenii were distributed in open areas with low competition for light, between 80 and 800 m. These latter three species have the potential to become ornamental plants, being characterized by bright and colourful upright inflorescences. The data presented here will help in providing a valuable contribution to the conservation and use of the wild bananas in northern Viet Nam.

UNLABELLED: Collection and storage of crop wild relative (CWR) germplasm is crucial for preserving species genetic diversity and crop improvement. Nevertheless, much of the genetic variation of CWRs is absent in ex situ collections and detailed passport data are often lacking. Here, we focussed on Musa balbisiana, one of the two main progenitor species of many banana cultivars. We investigated the genetic structure of M. balbisiana across its distribution range using microsatellite markers. Accessions stored at the International Musa Germplasm Transit Centre (ITC) ex situ collection were compared with plant material collected from multiple countries and home gardens from Vietnam. Genetic structure analyses revealed that accessions could be divided into three main clusters. Vietnamese and Chinese populations were assigned to a first and second cluster respectively. A third cluster consisted of ITC and home garden accessions. Samples from Papua New Guinea were allocated to the cluster with Chinese populations but were assigned to a separate fourth cluster if the number of allowed clusters was set higher. Only one ITC accession grouped with native M. balbisiana populations and one group of ITC accessions was nearly genetically identical to home garden samples. This questioned their wild status, including accessions used as reference for wild M. balbisiana. Moreover, most ITC accessions and home garden samples were genetically distinct from wild populations. Our results highlight that additional germplasm should be collected from the native distribution range, especially from Northeast India, Myanmar, China, and the Philippines and stored for ex situ conservation at the ITC. The lack of passport data for many M. balbisiana accessions also complicates the interpretation of genetic information in relation to cultivation and historical dispersal routes. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10722-022-01389-4. ispartof: GENETIC RESOURCES AND CROP EVOLUTION vol:69 issue:7 pages:2515-2534 ispartof: location:Netherlands status: published

Background and Aims Floral diversity as a result of plant–pollinator interactions can evolve by two distinct processes: shifts between pollination systems or divergent use of the same pollinator. Although both are pollinator driven, the mode, relative importance and interdependence of these different processes are rarely studied simultaneously. Here we apply a phylogenetic approach using the Balsaminaceae (including the species-rich genus Impatiens) to simultaneously quantify shifts in pollination syndromes (as inferred from the shape and colour of the perianth), as well as divergent use of the same pollinator (inferred from corolla symmetry). Methods For 282 species we coded pollination syndromes based on associations between floral traits and known pollination systems, and assessed corolla symmetry. The evolution of these traits was reconstructed using parsimony- and model-based approaches, using phylogenetic trees derived from phylogenetic analyses of nuclear ribosomal and plastid DNA sequence data. Key Results A total of 71 % of studied species have a bee pollination syndrome, 22 % a bimodal syndrome (Lepidoptera and bees), 3 % a bird pollination syndrome and 5 % a syndrome of autogamy, while 19 % of species have an asymmetrical corolla. Although floral symmetry and pollination syndromes are both evolutionarily labile, the latter shifts more frequently. Shifts in floral symmetry occurred mainly in the direction towards asymmetry, but there was considerable uncertainty in the pattern of shift direction for pollination syndrome. Shifts towards asymmetrical flowers were associated with a bee pollination syndrome. Conclusion Floral evolution in Impatiens has occurred through both pollination syndrome shifts and divergent use of the same pollinator. Although the former appears more frequent, the latter is likely to be underestimated. Shifts in floral symmetry and pollination syndromes depend on each other but also partly on the region in which these shifts take place, suggesting that the occurrence of pollinator-driven evolution may be determined by the availability of pollinator species at large geographical scales.

The ability of seeds to withstand drying is fundamental to ex situ seed conservation but drying responses are not well known for most wild species including crop wild relatives. We look at drying responses of seeds of Musa acuminata and Musa balbisiana, the two primary wild relatives of bananas and plantains, using the following four experimental approaches: (i) We equilibrated seeds to a range of relative humidity (RH) levels using non-saturated lithium chloride solutions and subsequently measured moisture content (MC) and viability. At each humidity level we tested viability using embryo rescue (ER), tetrazolium chloride staining and germination in an incubator. We found that seed viability was not reduced when seeds were dried to 4% equilibrium relative humidity (eRH; equating to 2.5% MC). (ii) We assessed viability of mature and less mature seeds using ER and germination in the soil and tested responses to drying. Findings showed that seeds must be fully mature to germinate and immature seeds had negligible viability. (iii) We dried seeds extracted from ripe/unripe fruit to 35-40% eRH at different rates and tested viability with germination tests in the soil. Seeds from unripe fruit lost viability when dried and especially when dried faster; seeds from ripe fruit only lost viability when fast dried. (iv) Finally, we dried and re-imbibed mature and less mature seeds and measured embryo shrinkage and volume change using X-ray computer tomography. Embryos of less mature seeds shrank significantly when dried to 15% eRH from 0.468 to 0.262 mm3, but embryos of mature seeds did not. Based on our results, mature seeds from ripe fruit are desiccation tolerant to moisture levels required for seed genebanking but embryos from immature seeds are mechanistically less able to withstand desiccation, especially when water potential gradients are high. ispartof: Conservation Physiology vol:10 issue:1 pages:1-16 ispartof: location:England status: Published online

Collection and storage of crop wild relative (CWR) germplasm is crucial for preserving species genetic diversity and crop improvement. Nevertheless, much of the genetic variation of CWRs is absent in ex situ collections and detailed passport data are often lacking. Here, we focussed onThe online version contains supplementary material available at 10.1007/s10722-022-01389-4.

Crop wild relatives (CWR) are an indispensable source of alleles to improve desired traits in related crops. While knowledge on the genetic diversity of CWR can facilitate breeding and conservation strategies, it has poorly been assessed. Cultivated bananas are a major part of the diet and income of hundreds of millions of people and can be considered as one of the most important fruits worldwide. Here, we assessed the genetic diversity and structure of Musa balbisiana, an important CWR of plantains, dessert and cooking bananas. Musa balbisiana has its origin in subtropical and tropical broadleaf forests of northern Indo-Burma. This includes a large part of northern Vietnam where until now, no populations have been sampled. We screened the genetic variation and structure present within and between 17 Vietnamese populations and six from China using 18 polymorphic SSR markers. Relatively high variation was found in populations from China and central Vietnam. Populations from northern Vietnam showed varying levels of genetic variation, with low variation in populations near the Red River. Low genetic variation was found in populations of southern Vietnam. Analyses of population structure revealed that populations of northern Vietnam formed a distinct genetic cluster from populations sampled in China. Together with populations of central Vietnam, populations from northern Vietnam could be subdivided into five clusters, likely caused by mountain ranges and connected river systems. We propose that populations sampled in central Vietnam and on the western side of the Hoang Lien Son mountain range in northern Vietnam belong to the native distribution area and should be prioritised for conservation. Southern range edge populations in central Vietnam had especially high genetic diversity, with a high number of unique alleles and might be connected with core populations in northern Laos and southwest China. Southern Vietnamese populations are considered imported and not native. ispartof: PLOS ONE vol:16 issue:6 ispartof: location:United States status: published

Fusarium is one of the most important fungal genera of plant pathogens that affect the cultivation of a wide range of crops. Agricultural losses caused by Fusarium oxysporum f. sp. cubense (Foc) have a direct effect on the income, subsistence and nourishment of thousands of smallholder farmers worldwide. In addition, also commercial growers are strongly affected. For Viet Nam, predictions on the impact of Foc for the future are dramatic with an estimated loss in banana production area of 8% within the next 5 years and up to 71% within the next 25 years. In the current study we applied a combined morphological - molecular approach to assess the taxonomic identity and phylogenetic position of the different Foc isolates that were collected in northern Viet Nam. In addition, we aim to estimate the proportion of the different Fusarium races that are infecting bananas in northern Viet Nam. The morphology of the isolates was investigated by growing the collected Fusarium isolates on four distinct nutritious media (PDA, SNA, CLA, and OMA). Molecular phylogenetic relationships were inferred by sequencing partial rpb1, rpb2 and tef1a genes and adding the obtained sequences into a large phylogenetic framework. The present study showed that Foc Race 1 is the most common strain in northern Viet Nam, causing 74% of all the infections. A more in-depth molecular characterization shows that of the Foc Race 1 infections, 92% are caused by Fusarium tardichlamydosporum and 8% by F. duoseptatum. Compared to Foc Race 1, Foc TR4 (represented by F. odoratissimum) account for only 10.5% of the Fusarium wilting in northern Viet Nam demonstrating that Foc TR4 is not yet a dominant strain in the region. Foc Race 2 infections of Vietnamese bananas also account for 10.5% of the Fusarium wilting in northern Viet Nam. One of the isolates cultured from diseased bananas collected in northern Viet Nam was phylogenetically not positioned within the F. oxysporum species complex (FOSC), but in contrast fell within the Fusarium fujikuroi species complex (FFSC). As a result, it is possible that a new pathogen for bananas has been found. Besides being present on several ABB ‘Tay banana’, Foc Race 1 was also found as pathogen on wild Musa lutea, showing the importance of wild bananas as possible sink for Foc.

Background Conservation of plant genetic resources, including the wild relatives of crops, plays an important and well recognised role in addressing some of the key challenges faced by humanity and the planet including ending hunger and biodiversity loss. However, the genetic diversity and representativeness of ex situ collections, especially that contained in seed collections, is often unknown. This limits meaningful assessments against conservation targets, impairs targeting of future collecting and limits their use. We assessed genetic representation of seed collections compared to source populations for three wild relatives of bananas and plantains. Focal species and sampling regions were M. acuminata subsp. banksii (Papua New Guinea), M. balbisiana (Viet Nam) and M. maclayi s.l. (Bougainville, Papua New Guinea). We sequenced 445 samples using suites of 16–20 existing and newly developed taxon-specific polymorphic microsatellite markers. Samples of each species were from five populations in a region; 15 leaf samples from different individuals and 16 seed samples from one infructescence (‘bunch’) were analysed for each population. Results Allelic richness of seeds compared to populations was 51, 81 and 93% (M. acuminata, M. balbisiana and M. maclayi respectively). Seed samples represented all common alleles in populations but omitted some rarer alleles. The number of collections required to achieve the 70% target of the Global Strategy for Plant Conservation was species dependent, relating to mating systems. Musa acuminata populations had low heterozygosity and diversity, indicating self-fertilization; many bunches were needed (> 15) to represent regional alleles to 70%; over 90% of the alleles from a bunch are included in only two seeds. Musa maclayi was characteristically cross-fertilizing; only three bunches were needed to represent regional alleles; within a bunch, 16 seeds represent alleles. Musa balbisiana, considered cross-fertilized, had low genetic diversity; seeds of four bunches are needed to represent regional alleles; only two seeds represent alleles in a bunch. Conclusions We demonstrate empirical measurement of representation of genetic material in seeds collections in ex situ conservation towards conservation targets. Species mating systems profoundly affected genetic representation in seed collections and therefore should be a primary consideration to maximize genetic representation. Results are applicable to sampling strategies for other wild species.

Aim Crop wild relatives (CWR) are an essential source of genetic material for the improvement of certain traits in related crop species. Despite their importance, increasing public, scientific and political support, large gaps exist in the amount of genetic material collected and conserved of many CWR. Here, we construct a dataset on the distribution of wild banana species (Musa spp.) and assess their risk and conservation status. We deal with the following questions: (a) What areas are potentially suitable for wild banana species? (b) How much of the wild banana diversity is currently at risk or insufficiently conserved ex and in situ?Location Native distribution area of wild banana species, ranging from the north-eastern states of India to north-eastern Australia.Methods We assessed the potential environmental range of wild species using a species distribution modelling approach with MaxEnt. Extinction risk was evaluated following IUCN criterion B, and the ex and in situ conservation status was assessed using an indicator for biodiversity and sustainable development targets.Results We found that 11 out of 59 assessed species can be considered as vulnerable and nine as endangered. Highest species richness was found along the border of south China and northern Vietnam, in the north-eastern states of India and on the Malayan peninsula. Our distribution modelling approach indicates that the northern Indo-Burmese region has the highest environmental suitability for most wild banana species and that lowland rain forests in general are highly suitable for bananas. Assessment of in and ex situ conservation status indicates that 56 out of 59 assessed species are currently insufficiently conserved ex situ and that 49 are of high priority for further conservation. Additional in situ conservation is of high priority for six species and of medium priority for 40 species.Main conclusions To date, little of the banana CWR are sufficiently conserved both in and ex situ.

Seed conservation of banana crop wild relatives (Musa L. spp.) is limited because of lack of knowledge about their germination ecology. Musa acuminata Colla, the most important banana crop wild relative, is distributed in tropical and subtropical Asian and Pacific rainforests and colonizes disturbed sites. The role of temperature in stimulating/inhibiting germination to detect disturbance when canopy gaps are formed is not well known. We assessed seed germination thermal requirements of three subspecies of M. acuminata using nine seed accessions which had been stored in the Millennium Seed Bank. Diurnally alternating temperature cycles were almost completely essential for germination compared with constant temperatures. Germination was optimal when the upper temperature of a diurnal cycle was at 35°C; the lower temperature of the cycle was less important. Subspecies occurrence coordinates were used to extract climate temperature data which were then compared against the temperature requirements for germination from our experiment results. Maximum temperatures of the warmest month across subspecies ranges were close to but below optimal germination temperatures, as were diurnal ranges, suggesting soil-warming at the micro-climate level following gap creation is important for M. acuminata seed germination. Additionally, pre-treatment for 3 months at 60% relative humidity at constant 25°C improved germination from 14 ± 10 (mean, standard deviation) to 41 ± 29% suggesting a period in the soil seed bank under the canopy may increase sensitivity to alternating temperature cycles. Overall viability was low (49 ± 28%), and considerable variance was caused by the different accessions. Germination remained somewhat inconsistent.

Phylogenies are a central and indispensable tool for evolutionary and ecological research. Even though most angiosperm families are well investigated from a phylogenetic point of view, there are far less possibilities to carry out large-scale meta-analyses at order level or higher. Here, we reconstructed a large-scale dated phylogeny including nearly 1/8th of all angiosperm species, based on two plastid barcoding genes, matK (incl. trnK) and rbcL. Novel sequences were generated for several species, while the rest of the data were mined from GenBank. The resulting tree was dated using 56 angiosperm fossils as calibration points. The resulting megaphylogeny is one of the largest dated phylogenetic tree of angiosperms yet, consisting of 36,101 sampled species, representing 8,399 genera, 426 families and all orders. This novel framework will be useful for investigating different broad scale research questions in ecological and evolutionary biology., info:eu-repo/semantics/published

Crop wild relatives (CWRs) play a key role in crop breeding by providing beneficial trait characteristics for improvement of related crops. CWRs are more efficiently used in breeding if the plant material is genetically characterized, but the diversity in CWR genetic resources has often poorly been assessed. Seven seed collections ofMusa balbisiana, an important CWR of dessert and cooking bananas, originating from three natural populations, two feral populations and twoex situfield collections were retrieved and their genetic diversity was quantified using 18 microsatellite markers to select core subsets that conserve the maximum genetic diversity. The highest genetic diversity was observed in the seed collections from natural populations of Yunnan, a region that is part ofM. balbisiana's centre of origin. The seeds from theex situfield collections were less genetically diverse, but contained unique variation with regards to the diversity in all seed collections. Seeds from feral populations displayed low genetic diversity. Core subsets that maximized genetic distance incorporated almost no seeds from theex situfield collections. In contrast, core subsets that maximized allelic richness contained seeds from theex situfield collections. We recommend the conservation and additional collection of seeds from natural populations, preferentially originating from the species' region of origin, and from multiple individuals in one population. We also suggest that the number of seeds used forex situseed bank regeneration must be much higher for the seed collections from natural populations.

In this work, we compare the genetic differentiation and structure of populations of two closely related Centaurium species that display a large variation in floral morphology across two geographic regions in Europe. The populations of both species show opposite patterns of genetic differentiation and structure, and the patterns are reversed between the two regions. For both species, we find a strong link between these patterns and the differences in floral morphology observed in the sampled populations., The genetic diversity and structure of plant populations are determined by the interaction of three distinct processes: gene flow, genetic drift and natural selection. These processes are to some extent dependent on the mating system of plants, which in turn is largely determined by floral morphology and the level of herkogamy in particular. In this study, we used molecular markers to investigate the impact of floral morphology on genetic differentiation and structure in two closely related Centaurium species that display large variation in floral morphology across two distinct geographic regions in Europe (mainland Europe and the UK). Our results showed that genetic differences between regions and populations within regions were similar for both species, but that patterns of genetic structure largely depended on the observed variation in floral morphology. Populations of Centaurium erythraea showed higher genetic differentiation and clear isolation by distance (IBD) in mainland Europe, but limited IBD in the UK. Opposite patterns were found in Centaurium littorale, with higher genetic differentiation and significant IBD in populations sampled in the UK and lower genetic differentiation in Continental populations with no pattern of IBD. Overall, these results indicate that variation in floral morphology has a profound impact on structuring of genetic diversity, with populations displaying low levels of herkogamy showing the strongest patterns of genetic structuring and the reverse pattern in populations showing high levels of herkogamy.

A new Impatiens species from Mozambique, Impatiens wuerstenii, is described and illustrated. The material used for the description was initially mistaken for the morphologically similar Impatiens species I. psychadelphoides, a known endemic from Mozambique. However, a combined molecular – morphological study demonstrates that the populations found on Mount Gorongosa do not belong to I. psychadelphoides but are a species on their own. Phylogenetic analyses based on chloroplast and nuclear gene markers demonstrate that I. wuerstenii is sister to the floral morphologically distinct I. salpinx, and that I. psychadelphoides and I. cecilii are sister to that lineage. The presence of a new endemic species on Mount Gorongosa indicates the importance of this mountain area on the overall biodiversity of the region and emphasizes the need for a more thorough conservation and biological exploration of the mountain.