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Port-Vila, Vanuatu

Vandenbroucke H.,CIRAD - Agricultural Research for Development | Mournet P.,CIRAD - Agricultural Research for Development | Malapa R.,VARTC | Glaszmann J.-C.,CIRAD - Agricultural Research for Development | And 2 more authors.
Genome | Year: 2015

Kava (Piper methysticum) is a major cash crop in the Pacific. The aim of this study was to assess genetic variation among 103 accessions of kava using SSRs and DArTs. Genetic structure was determined using clustering analyses (WPGMA) and principal coordinate analyses (PCA). Thirteen SSR primers and 75 DArT markers were found polymorphic, and the two types of markers generated similar clustering patterns. Genetic distances ranged from 0 to 0.65 with an average of 0.24 using SSRs and from 0 to 0.64 with an average of 0.24 using DArT. Eleven genotypes were identified with SSR while 28 genotypes were identified with DArT markers. By combining the two sets of markers, a total of only 30 distinct genotypes were observed. In the Vanuatu archipelago, noble cultivars originating from different islands clustered together within a very narrow genetic base despite their diversity of morphotypes. SSR and DArT fingerprints allowed the identification of kava cultivars unsuitable for consumption, so called two-days, and clearly differentiated the wild types classified as P. methysticum var. wichmannii from the cultivars as var. methysticum. Molecular data reveals that all noble cultivars evolved by the predominance of clonal selection. Although they are represented by clearly distinct morphotypes, these cultivars are genetically vulnerable and their potential to adapt to forthcoming changes is limited. These newly developed markers provide high resolution and will be useful for kava diversity analyses and quality assessment. © 2015 Published by NRC Research Press. Source

Blomme G.,Commodity Systems and Genetic Resources Programme | Ploetz R.,University of Florida | De Langhe E.,Catholic University of Leuven | Geering A.,Queensland Alliance for Agriculture and Food Innovation QAAFI | And 7 more authors.
Annals of Applied Biology | Year: 2013

The genus Musa is not native to Africa. It evolved in tropical Asia, from southwest India eastward to the island of New Guinea. There is a growing circumstantial evidence which suggests that the East African Highland banana and the tropical lowland plantain were cultivated on the African continent since before 1 AD. It is also probable that ABB cooking and AB and AAB dessert cultivars were brought to the continent from India by Arabian traders from 600 AD, and that these were disseminated throughout East Africa. During the colonial era, the main centres of distribution for banana cultivars were botanical gardens, such as Zomba in Malawi, Entebbe in Uganda and Amani in Tanzania. It appears that the very early introductions of Highland banana and plantain arrived in Africa as a relatively clean material without the conspicuous pests and diseases that affect them in Asia. In contrast, several devastating problems now impact the crop in Africa, including nematodes, the borer weevil and diseases, most notably banana bunchy top, banana streak, Sigatoka leaf spots, Xanthomonas wilt and Fusarium wilt. We (a) provide chronological overviews of the first reports/observations of different Musa pests and pathogens/diseases in Africa, (b) highlight specific examples of when a pest or pathogen/disease was introduced via planting materials and (c) give recent examples of how the pests and pathogens spread to new regions via planting materials. In total, these production constraints threaten banana and plantain production throughout the continent and impact those who can ill afford lost production, the small-holder producer. Our intent in this review is to highlight the significance of these problems and the great importance that infested planting materials have played in their development. © 2012 Association of Applied Biologists. Source

Cubry P.,CIRAD - Agricultural Research for Development | Cubry P.,Michelin | Pujade-Renaud V.,UMR AGAP | Pujade-Renaud V.,University Blaise Pascal | And 5 more authors.
Plant Breeding | Year: 2014

Despite its economic importance and recent genome release, the need for molecular tools for Hevea brasiliensis is high. In the frame of a disease resistance study, EST sequences were retrieved from public database or generated by sequencing SSH libraries. Sequences were trimmed and microsatellite motifs searched using an ad hoc bioinformatic pipeline, and pairs of primers for the amplification of candidate markers were generated. We found a total of 10 499 unigenes from both sources of sequences, and 673 microsatellites motifs were detected using the default parameters of the pipeline. Two hundred sixty-four primer pairs were tested and 226 (85.6%) successfully amplified. Out of the amplified candidate markers, 164 exhibited polymorphism. Relationships based on dendrograms using simple matching index and diversity statistics based on EST-SSRs were compared with Genomic SSRs, showing the potentialities of EST-derived microsatellites for resistance studies but also for population genetics approaches. © 2014 Blackwell Verlag GmbH. Source

Lachenaud P.,UPR 106 | Fouet O.,UMR AGAP | Couturier C.,British Petroleum | Lanaud C.,UMR AGAP
Genetic Resources and Crop Evolution | Year: 2015

The wild cacao trees (Theobroma cacao L.) of French Guiana were investigated during several survey and collecting expeditions between 1985 and 1995. The many studies made of this material showed it to be highly original. New surveys were undertaken in May 2012 in south-eastern French Guiana, in the upper reaches of the Tanpok River and some of its tributaries, in order to enrich the cacao collection preserved at the Paracou-Combi site at Sinnamary (French Guiana). One of the aims of the expedition was to determine whether the populations from the upper-Tanpok were original and different from those already represented in the collection. From the 2012 mission four populations were identified. The material collected was described (location, tree and pod morphology). Genetic diversity of the collected genotypes and various controls was studied using SSR markers. The collected trees belonged to the “Guiana” group, but did not reveal any distinctive feature within the group. The genetic diversity encountered was low (He = 0.124). The outcome of these surveys is positive, since new populations were located. In order to preserve and carry out phenotypical studies (agro-morphology) on the new material collected, a plot was planted at Paracou-Combi in January 2013. © 2015 Springer Science+Business Media Dordrecht Source

Gwali S.,Makerere University | Gwali S.,National Forestry Resources Research Institute NaFORRI | Vaillant A.,UMR AGAP | Nakabonge G.,Makerere University | And 4 more authors.
Forests Trees and Livelihoods | Year: 2015

Shea trees (Vitellariaparadoxa C. F. Gaertn.) are classified locally into several folk or ethno-varieties by farmers in Uganda. It is, however, not clear whether this folk classification is supported by genetic differentiation between ethno-varieties. Genetically linked traits from folk classification are useful in conservation and breeding programmes. A total of 118 individual shea trees constituting 28 ethno-varieties sampled from three farming systems of Uganda were analysed using microsatellite markers. The number of alleles amplified per microsatellite locus ranged from 6 to 13 with an average of 9.5, with a total of 106 alleles identified. Observed (Ho) and expected heterozygosity (He) per locus ranged from 0.366 to 0.934 and 0.580 to 0.840, respectively. Mean Ho and He values for all loci across all ethno-varieties were 0.633 and 0.727, respectively. Analysis of molecular variance indicated that most of the variation (86.28%) occurred within individual trees; 11.25% was found among individual trees within ethno-varieties while 2.47% was found among ethno-varieties. The in-breeding index (f = 0.130), fixation index (θP = 0.025), gene flow value (Nm = 6.56) and cluster analysis show that all shea tree ethno-varieties were a single out-crossing population with very low genetic differentiation and high gene flow. The low differentiation in shea tree ethno-varieties was most likely due to the utilization of non-genetic traits in folk classification. However, while ethno-variety genetic structure was very weak, overall spatial population structure indicated the presence of three populations (West Nile, Northern and Teso). The West Nile population was more distantly related to the other two most likely due to isolation barriers such as the Rift Valley, Lake Albert and River Nile. © 2015 Taylor & Francis. Source

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