Sequencing wild and cultivated cassava and related species reveals extensive interspecific hybridization and genetic diversity

Cassava (Manihot esculenta) provides calories and nutrition for more than half a billion people. It was domesticated by native Amazonian peoples through cultivation of the wild progenitor M. esculenta ssp. flabellifolia and is now grown in tropical regions worldwide. Here we provide a high-quality genome assembly for cassava with improved contiguity, linkage, and completeness; almost 97% of genes are anchored to chromosomes. We find that paleotetraploidy in cassava is shared with the related rubber tree Hevea, providing a resource for comparative studies. We also sequence a global collection of 58 Manihot accessions, including cultivated and wild cassava accessions and related species such as Ceará or India rubber (M. glaziovii), and genotype 268 African cassava varieties. We find widespread interspecific admixture, and detect the genetic signature of past cassava breeding programs. As a clonally propagated crop, cassava is especially vulnerable to pathogens and abiotic stresses. This genomic resource will inform future genome-enabled breeding efforts to improve this staple crop

Ipomoea batatas (L.) Lam.: a rich source of lipophilic phytochemicals

The lipophilic extracts from the storage root of 13 cultivars of sweet potato (Ipomoea batatas (L.) Lam.) were evaluated by gas chromatography-mass spectrometry with the aim to valorize them and offer information on their nutritional properties and potential health benefits. The amount of lipophilic extractives ranged from 0.87 to 1.32% dry weight. Fatty acids and sterols were the major families of compounds identified. The most abundant saturated and unsaturated fatty acids were hexadecanoic acid (182-428 mg/kg) and octadeca-9,12-dienoic acid (133-554 mg/kg), respectively. β-Sitosterol was the principal phytosterol, representing 55.2-77.6% of this family, followed by campesterol. Long-chain aliphatic alcohols and α-tocopherol were also detected but in smaller amounts. The results suggest that sweet potato should be considered as an important dietary source of lipophilic phytochemicals.info:eu-repo/semantics/publishedVersio

Kava and ethno-cultural identity in Oceania

Garibaldi and Turner (Ecol Soc 9:1, 5, 2004) explain the role that particular plants play in facilitating the shared ancestry, practices, and social experience of an ethnicity. This can include spiritual connections, cultural expression and practice, ceremony, exchange, linguistic reflection, socialization, and medicinal and/or dietary systems. They term these plants “cultural keystone species” and icons of identity, plants that if removed would cause some disruptions to the cultural practices and identity of an ethnic group. Undoubtedly, kava (Piper methysticum) is the cultural keystone species for many Oceanic and Pacific peoples, a “differentiating element of common culture” (Zagefka, Ethnicity, concepts of. In: Smith AD, Hou X, Stone J, Dennis R, Rizova P (eds) The Wiley Blackwell encyclopedia of race, ethnicity, and nationalism. West Wiley, Sussex, pp 761–763, 2016) informing their ethno-cultural identity. That influence is also extending to new non-Pacific Island user groups who have embraced elements of kava ethno-cultural identity in what has been termed diasporic identity formation in reverse. This chapter will discuss kava with specific reference to ethnic positionality in Fiji while recognizing the tensions from inside and outside the region that support and threaten the continuance of the kava drinking tradition

Development and characterization of polymorphic microsatellite markers in taro (Colocasia esculenta)

Microsatellite-containing sequences were isolated from enriched genomic libraries of taro (Colocasia esculenta (L.) Schott). The sequencing of 269 clones yielded 77 inserts containing repeat motifs. The majority of these (81.7%) were dinucleotide or trinucleotide repeats. The GT/CA repeat motif was the most common, accounting for 42% of all repeat types. From a total of 43 primer pairs designed, 41 produced markers within the expected size range. Sixteen (39%) were polymorphic when screened against a restricted set of taro genotypes from Southeast Asia and Oceania, with an average of 3.2 alleles detected on each locus. These markers represent a useful resource for taro germplasm management, genome mapping, and marker-assisted selection

Spatially structured genetic diversity of the Amerindian yam (Dioscorea trifida L.) assessed by SSR and ISSR markers in Southern Brazil

Dioscorea trifida L. (Dioscoreaceae) is among the economically most important cultivated Amerindian yam species, whose origin and domestication are still unresolved issues. in order to estimate the genetic diversity maintained by traditional farmers in Brazil, 53 accessions of D. trifida from 11 municipalities in the states of São Paulo, Santa Catarina, Mato Grosso and Amazonas were characterized on the basis of eight Simple Sequence Repeats (SSR) and 16 Inter Simple Sequence Repeats (ISSR) markers. the level of polymorphism among the accessions was high, 95 % for SSR and 75.8 % for ISSR. the SSR marker showed higher discrimination power among accessions compared to ISSR, with D parameter values of 0.79 and 0.44, respectively. Although SSR and ISSR markers led to dendrograms with different topologies, both separated the accessions into three main groups: I-Ubatuba-SP; II-Iguape-SP and Santa Catarina; and III-Mato Grosso. the accessions from Amazonas State were classified in group II with SSR and in a separate group with ISSR. Bayesian and principal coordinate analyzes conducted with both molecular markers corroborated the classification into three main groups. Higher variation was found within groups in the AMOVA analysis for both markers (66.5 and 60.6 % for ISSR and SSR, respectively), and higher Shannon diversity index was found for group II with SSR. Significant but low correlations were found between genetic and geographic distances (r = 0.08; p = 0.0007 for SSR and r = 0.16; p = 0.0002 for ISSR). Therefore, results from both markers showed a slight spatially structured genetic diversity in D. trifida accessions maintained by small traditional farmers in Brazil.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ São Paulo, Luiz de Queiroz Coll Agr, Dept Genet, BR-13400970 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Biol Sci, BR-09972270 São Paulo, BrazilUniv Calif Davis, Dept Plant Sci MS1, Sect Crop & Ecosyst Sci, Davis, CA 95616 USAUniversidade Federal de São Paulo, Dept Biol Sci, BR-09972270 São Paulo, BrazilFAPESP: 2007/04805-2Web of Scienc

High genetic diversity among and within bitter manioc varieties cultivated in different soil types in Central Amazonia

Although manioc is well adapted to nutrient-poor Oxisols of Amazonia, ethnobotanical observations show that bitter manioc is also frequently cultivated in the highly fertile soils of the floodplains and Amazonian dark earths (ADE) along the middle Madeira River. Because different sets of varieties are grown in each soil type, and there are agronomic similarities between ADE and floodplain varieties, it was hypothesized that varieties grown in ADE and floodplain were more closely related to each other than either is to varieties grown in Oxisols. We tested this hypothesis evaluating the intra-varietal genetic diversity and the genetic relationships among manioc varieties commonly cultivated in Oxisols, ADE and floodplain soils. Genetic results did not agree with ethnobotanical expectation, since the relationships between varieties were variable and most individuals of varieties with the same vernacular name, but grown in ADE and floodplain, were distinct. Although the same vernacular name could not always be associated with genetic similarities, there is still a great amount of variation among the varieties. Many ecological and genetic processes may explain the high genetic diversity and differentiation found for bitter manioc varieties, but all contribute to the maintenance and amplification of genetic diversity within the manioc in Central Amazonia. © 2017, Sociedade Brasileira de Genética