Manihot Species Research Articles

Projected effects of climate change on the potential distribution range of Manihot species endemic to Northeast Brazil.

Climate change is a global concern, with far-reaching implications for biodiversity and ecosystems. Understanding impact on species distribution is crucial for effective conservation strategies. The aims of this study were to evaluate the projected effects of climate change on the potential distribution of Manihot species endemic to Northeast Brazil and estimate the presence of climate suitability within protected areas in the future. We used ecological niche models to assess the potential distribution of 11 endemic species, providing predictions of current and future scenarios using an optimistic and pessimistic climate change scenario. The results revealed that in the optimistic scenario, 45% of the species may experience a partial reduction in their potential distribution range by 2100, and this percentage increases to 54% in the pessimistic scenario. Other species, on the other hand, will increase their potential distribution. The climatically suitable area for most species will be inserted in some protected areas, but species with limited current distribution and decreasing potential range must be prioritized for conservation. This study provides valuable information about the future potential distribution of endemic species of Manihot.

A look at endemic manihot species for northeastern Brazil: Taxonomy, richness, distribution and conservation

A look at endemic manihot species for northeastern Brazil: Taxonomy, richness, distribution and conservation

Germination niche of a pioneer woody species (Manihot grahamii hook.): a strategy of seed heat stimulation to cope with disturbance in dry subtropical forests

AbstractLight and temperature conditions trigger germination in specific temporal windows and microhabitats, thus determining the germination niche of plant species. Manihot species grow in fire-prone ecosystems and their seeds show heat tolerance. Successful establishment in disturbed environments might be related to seed attributes that allow seeds to cope with or avoid stressful environments. We studied some characteristics of the germination niche of Manihot grahamii, a pioneer woody species present in dry subtropical forests of central Argentina, to understand its successful establishment in disturbed environments. We evaluated the germination ecology of the seeds of M. grahamii with the aims to (1) characterize seed traits (viability, mass and moisture content); (2) determine whether it has dormancy and if it is physical or physiological; (3) evaluate the effect of several pre-treatments (gibberellic acid, after ripening, dry prechilling and dry prechilling + warm) on seed dormancy; and (4) assess the effect of different environmental events of high temperatures on the germination process simulating two treatments: fire intensities (with three levels of heat shock) and a gap temperature. M. grahamii seeds have large mass (0.24 g), low moisture content (8%), physiological dormancy, negative photoblastic behaviour and high heat tolerance. Dormancy was alleviated and seeds became insensitive to light when they were exposed to pre-treatments of dry prechilling + warm and high-temperature treatments. This germination strategy promotes secure germination timing into the rainy season on undisturbed habitats as well as a cue for competition-released gaps which in turn favour recruitment in open, disturbed and dry habitats, respectively. In the context of global change, with an increasing habitat fragmentation and fire frequency, M. grahamii could become more abundant and extend its geographic distributional range in central Argentina.

In situ ruminal degradability of forage cactus-based diets associated with pornunça silage

The knowledge of ruminal degradation kinetics of forage cactus-based diets associated with Euphorbiaceae species of the genus Manihot assist in understanding nutrient quality and use, contributing to the indication of combinations of these ingredients in ruminant diets. This study aimed to evaluate the in situ ruminal degradability of diets with increasing association of forage cactus Elephant Ear (MEE) and pornunça (Manihot sp.) silage, as well as to analyze and evaluate the indigestible neutral detergent fiber (FDNi) content of forage cactus MEE and pornunça silage. The treatments consisted of diets with cactus pear associated with pornunça silage in the roughage portion in the proportions of 375, 250, 125 and 0 g kg-1 of DM. The feed was composed of 50% roughage and 50% concentrate of dry matter. Incubation times of 0, 6, 12, 24, 48, 96, and 144 hours were evaluated for the ingredients and 0, 2, 4, 6, 8, 12, 24, 48, 72, and 96 hours for the diets. Incubation to obtain the iNDF was given for 288 hours. The experimental design consisted of randomized blocks, with three replications. Regarding roughage ingredients, MEE showed higher average disappearance, potential degradability (PD), and effective degradability (ED) in relation to pornunça silage, as well as lower NDFi content. The proportion of 375 g kg-1 MEE and 125 g kg-1 pornunça silage provided higher fractions a, b, and c, increasing ED considering the three passage rates, with higher PD. In conclusion, the association between MEE and pornunça silage at a proportion of 375 g kg-1 MEE and125g kg-1 pornunça silage of the roughage portion increases the in situ degradability of dry matter, crude protein, and neutral detergent fiber.

DETERMINANTS OF OUTPUT OF CASSAVA (MANIHOT SPECIES) PRODUCTION IN ABUJA, NIGERIA

This research study focused on determinants of the output of cassava (Manihot species) production in Abuja, Nigeria. Multi-stage method of sampling was used. One hundred (100) cassava farmers were sampled and selected. Primary data were obtained through the use of a well-designed and also well-structured questionnaire. Data were analyzed using econometrics and statistical tools. The results show that 87% of cassava producers were between 31 to 50 years of age. About 72% had formal education and were literate. Averagely, they had 4.76 hectares of cassava farmland. The estimated gross margin (GM) and net farm income (NFI) of cassava production per hectare were 1,464, 162.72 Naira and 1, 453, 752.49 Naira respectively. This implies that cassava production was profitable and worthwhile. Farm size and fertilizer input were statistically significant factors influencing the output of cassava production. Age, labour input, and cassava cuttings were statistically significant factors influencing the output of cassava production. While chemical input statistically and significantly influenced the output of cassava production. The constraints facing cassava producers were the unavailability of improved cassava cuttings, the high cost of farm inputs, insecurity, inadequate extension services, and inadequate finances. The research study recommends that improved cassava cuttings should be made available to farmers for increased productivity. Extension officers should be employed to disseminate innovations, research findings, and new farm technologies to cassava farmers. Credit or loan facilities should be made available to cassava producers at low-interest rates.

Rise in temperature increases growth and yield of Manihot sp. plants

The selection of native forage species with yield potential under climate change scenarios can strengthen resilience of the Brazilian semiarid region. This study aimed to evaluate the effect of increasing temperature on growth and morphological and yield responses of plants of the genus Manihot. The experimental design was completely randomized in a 2×9 factorial arrangement (two temperature regimes and nine genotypes). The increase in temperature promoted higher plant dry mass (PDM) for genotypes A:24, A:79, A:102, A:EL, and A:GO during establishment. The percentage of leaves was reduced with the highest temperatures in the establishment, except for genotypes A:20, A:21, and A:GO. The increase in temperature during regrowth increased leaf dry mass (LDM) and reduced the leaf to stem ratio, except for A:24, A:79, and A:102, which presented similar values at both temperatures. Species of the genus Manihot respond differently to the 4.8 °C increase in air temperature. The increase in temperature shows a positive impact on the biomass production of species of this genus.

Effects of Processing Methods on the Cyanide Level of Fufu (A Manihot Species Product)

The work on the effects of processing method on the cyanide content of fufu was carried out using standard chemical procedures. The processing methods include: wet cooking and pounding, and the dry-stirred methods. The cyanide content of samples from both processing methods was determined using the alkaline titration method. The results obtained showed that the cyanide content of the wet cooked and pounded fufu was 20.52 mg/kg while that of the dry cooked and stirred sample was 18.36 mg/kg. The raw uncooked cassava paste had a cyanide level of 42.12 mg/kg while the standard WHO permissible limit for cyanide in cassava is 10 mg/kg. Processing reduces appreciably the cyanide level in cassava but the present study shows that the dry cooking with stirring is more effective than the wet cooking and pounding process in the reduction of cyanide in fufu. Thorough processing of cassava meal is emphasized to remove much of the toxic cyanide content for the safety of consumers.

Belenocarpa tertiara (Berry) gen. et comb. nov. (Euphorbiaceae): Fossil Fruits with Carunculate Seeds from the Oligocene of Peru

Premise of research. Three-dimensionally preserved fruits and seeds of “Jatropha” tertiara Berry from the early Oligocene of Peru have been reinvestigated on the basis of type material supplemented by more complete recently collected specimens.Methodology. The fossils were recovered by fracturing the weakly consolidated sediment. Extant and fossil fruits were studied with reflected light and by micro–computed tomography scanning.Pivotal results. The fruits are thin-walled prolate trilocular capsules that are hexagonal in cross section with prominent loculicidal and septicidal keels. The seeds are ovate in dorsiventral view, lenticular in cross section, and fitted with a large caruncle about half the length of the seed body. The large size and six-keeled aspect of the fruit distinguish this fossil from extant species of Jatropha and lead us to exclude it from the extant genus. We transfer this fossil species to the new genus Belenocarpa.Conclusions. Similarities to other genera, particularly some species of Manihot, indicate likely affinities between Belenocarpa and Euphorbiaceae subfamily Crotonoideae. The well-preserved, relatively large caruncles on these seeds, making up about one-third of the full seed length, are comparable to those seen on extant seeds known to be dispersed by ants and suggest that similar insect-plant associations were already present in South America by the Oligocene.

Advances in knowledge of Manihot (Euphorbiaceae) from Brazil.

Herbarium-based studies and extensive field work revealed the existence of a new species in the genus Manihot which is restricted to the municipality of Itirapina, in the state of São Paulo, Brazil. Characteristics such as the size and morphology of the leaves and bracts were important to recognize M. irregularis as a new taxon. Description, illustration, as well as comments on its morphology, distribution, conservation status, and a key for the identification of Manihot species for the state of São Paulo are presented.

Effects of different doses of paclobutrazol and sucrose in the minimum in vitro growth of wild species of Manihot

In vitro conservation, under minimal growth conditions, allows prolonging the periods between subcultures without affecting plant viability, besides reducing the contamination risk and the space required for cultivation. Experiments were conducted by using 8S as a basic culture medium, supplemented with combinations of five concentrations of paclobutrazol (PBZ - 0; 0.10; 0.20; 0.30 and 0.40 mg L-1) and sucrose (SUC - 0; 5; 10; 15; and 20 g L-1), resulting in 25 treatments, applied on three wild species: Manihot violaceae, M. flabellifolia and M. pseudoglaziovii. After 120 days of cultivation, the evaluated variables, namely plant height (cm) and the numbers of mini-cuttings with 1 cm, roots, shoots, green and senescent leaves, allowed verifying that, for the species M. pseudoglaziovii, the interaction of the 0.1 mg L-1 PBZ and 5 g L-1 SUC doses revealed a significant effect on the in vitro conservation. While for M. violacea, the combination of 10 g L-1 SUC and 0.2 mg L-1 PBZ is the most suitable for its conservation. Lastly, for M. flabelifolia, the concentrations used of SUC and PBZ did not prove efficient for in vitro conservation of the species.

In vitro multiplication of wild Manihot species with different naphthaleneacetic acid and benzylaminopurine concentrations

In vitro multiplication is an important tissue culture technique that is capable of efficiently producing seedlings at any scale. It is a propagation method based on the aseptic culture of small propagules in a suitable culture medium to enable plant regeneration. Multiplication experiments conducted in vitro to set protocols adapted to wild Manihot species have used modified mineral salts and MS vitamins as basic culture medium. Here, 25 treatments based on combinations of the regulators benzylaminopurine (BAP) and naphthaleneacetic acid (NAA) at 0, 0.025, 0.05, 0.075, and 0.1 mg L-1 were used for in vitro multiplication of three genotypes of wild Manihot species (M. violaceae Pohl Müll. Arg., M. pseudoglaziovii Pax & Hoff., and M. flabellifolia Pohl). Plant height and the number of 1 cm minicuttings, number of roots, shoots, green leaves and senescent leaves were recorded 120 days after explant inoculation. M. violaceae Pohl. Müll. Arg. and M. flabellifolia Pohl. presented favorable results with 0.05 and 0.025 mg L-1 NAA, respectively. Culture medium lacking NAA and BAP favored the in vitro growth of M. pseudoglaziovii Pax & Hoff.

From generalization to pollination syndromes: filtering and dependency on functional-group of pollinators in two cassava wild relatives

The reproductive biology of the cassava genus (Manihot, Euphorbiaceae) remains unknown, despite its relevance to humanity. Here, we investigated the pollination system of two cassava wild relatives concerning the filtering of visitors in unisexual flowers, the specialization–generalization degree, and verified the dependency on pollinators for seed production. We studied two monoecious species M. violacea and M. oligantha on floral traits differences and visitors during flowering periods in natural conditions. For specialization–generalization degree analysis, we grouped pollinators into functional groups. We performed hand pollination treatments to verify the mating system. About half of floral visitors visited a floral type exclusively. The sexually dimorphic floral display contributed to filtering abundant pollinators, whereas nectar traits acted as attractant filter. In addition to polysaccharides, a remarkable presence of alkaloids and terpenes was observed in the nectary tissue of both male and female flowers. The species exhibited specialization associated with distinct functional groups, M. violacea with bees and M. oligantha with flies. The two Manihot species presented self-compatibility and depend on pollinators to produce seeds and the threatened species M. oligantha manifested pollen limitation. Our findings evidence conspicuous filtering of visitors and consequently, a specialized pollination system emerged for the two Manihot species despite the apparent generalist flowers. The reproductive success relying on groups of abundant pollinators suggests a threatening scenario to cassava wild relatives due to the worldwide decline of insect abundance.

Cross-amplification and characterization of microsatellite markers in species of Manihot Mill. (Euphorbiaceae) endemic to the Brazilian Cerrado

ABSTRACT The genus Manihot Mill. contains about 120 species of which about 104 occur in Brazil. We tested the cross-amplification of ten microsatellite markers developed for Manihot esculenta in 15 species of Manihot endemic to the Brazilian Cerrado. We also evaluated the genetic diversity of Manihot irwinii, M. orbicularis, and M. purpureocostata. Ten pairs of primers were amplified among 14 species of Manihot. The percentage of polymorphic loci per species varied from 70 to 100 %. Nine markers showed amplification and polymorphism when evaluated on polyacrylamide gel. The markers were combined to form three sets for multiplex genotyping for genetic diversity analysis, and showed 51, 75, and 75 alleles in M. irwinii, M. orbicularis, and M. purpureocostata, respectively. The levels of genetic diversity for the transferred markers were high for the three species and proved to be useful for population genetics studies of species of Manihot endemic to the Cerrado. The results of this study will help to better understand the genetic diversity, taxonomy and relationships among species Manihot, and to develop conservation programs for the genus.

Synopsis of Manihot Species (Euphorbiaceae) with Non-lobed or Pinnately Lobed Leaves

A synopsis of 20 species of Manihot Mill. with non-lobed or pinnately lobed leaves is presented. Six of these species were included in the section Brevipetiolatae Pax by Rogers and Appan in the latest treatment of the genus. Molecular analyses show this is not a monophyletic section, although it is useful as a practical matter to treat this as a morphologically readily delimited group. We evaluate the species previously included in section Brevipetiolatae sensu Rogers and Appan, typify names where necessary, and synonymize the section. Twenty species are clarified and six lectotypes are designated. Three species previously put into synonymy, M. brachystachys Pax & K. Hoffm., M. linearifolia Müll. Arg., and M. mattogrossensis Pax & K. Hoffm., are here resurrected, and M. graminiformis M. Mend. & T. B. Cavalc. is described as a new species. An identification key and comments on the most similar morphological species, as well as ecological aspects and distribution for each species, are included.

Genetic divergence among accessions of Manihot spp.

The aim of this study was to perform a morphological and morphoagronomic analysis of wild Manihot species from a Brazilian semiarid region for inclusion in the collection at the Center for Agricultural Sciences, Federal University of Paraíba. To characterize the 55 accessions, 12 quantitative and 18 qualitative descriptors were used. A dissimilarity matrix was generated by Mahalanobis generalized distance (D²), and clusters were identified by the UPGMA method. It was possible to verify the formation of 8 dissimilar groups based on morphological characters and 5 groups based on morphometric characters, indicating the presence of genetic diversity among accessions. The evaluated morphometric variable with the greatest relative contribution was the length between the central lobe. Based on the dissimilarity matrix, the accessions 16 x 48 were the most genetically distant accessions, followed by 47 x 49. The accessions 4 Monteiro, 16 Soledad, 38 Boa Vista, 3 Pedra Lavrada, 7 Junco, 10 Barra de Santa Rosa, 21 Monteiro, and 39 Junco are the most promising and can be used as parents in breeding programs for this forage species.

Effects of structural complexity and habitat type on the gall distribution of Jatrophobia brasiliensis (Rübsaamen, 1907) (Diptera, Cecidomyiidae) in two host-species of Manihot (Euphorbiaceae)

In the present study, we evaluate the distribution of galls induced by Jatrophobia brasiliensis (Rübsaamen, 1907) in two species of Manihot (Manihot caerulescens Pohl and Manihot sp.). The study was performed in two Cerrado phytophysiognomies (typical savannah and rocky savannah) in Jequitaí municipality, Minas Gerais, Brazil. A total of 1,157 galls of Jatrophobia brasiliensis were analyzed, of which 459 galls in Manihot sp. and 698 galls in Manihot caerulescens. We found that plant height, crown diameter and number of leaves per branch positively influenced the number of galled leaves. Our results also showed that habitat type influenced the number of galled leaves and the gall size, with the rocky savannah presenting more and larger galls than the typical savannah. Our findings demonstrate that both intrinsic (related to host plant structure) and extrinsic factors (related to habitat type) influence the distribution of the galls induced by Jatrophobia brasiliensis on Manihot.

A new species and putative hybrids of Manihot (Euphorbiaceae) from Brazil

This work describes and illustrates the new species Manihot reflexifolia, sp. nov. and compares its leaf anatomy to Manihot reniformis and probable hybrids between the two species. Manihot reflexifolia is also compared to Manihot jacobinensis from which it can be distinguished by its cylindrical petioles, elliptical to short lanceolate, reflexed leaf lobes and staminate flowers restricted to the terminal portion of the inflorescence (upper half), while M. jacobinensis has dorsiventrally flattened petioles, suborbicular to obovate leaf lobes, and staminate flowers along the entire inflorescence axis. The new species is restricted to rocky outcrops of the Chapada Diamantina in central Bahia State, Brazil. An identification key to Manihot species from rocky outcrops of Chapada Diamantina is provided. The leaf anatomy of M. reflexifolia, M. reniformis and the putative hybrids was analyzed using optical and scanning electron microscopy. Leaf anatomy was sufficient to characterize M. reflexifolia, M. reniformis and the putative hybrids, as well as to identify the first two wild taxa as potential progenitors of the hybrids (M. reflexifolia × M. reniformis). The most useful anatomical characteristics were the morphology of the petiole and midrib, bundle sheath extension, organization and quantity of vascular bundles, organization and composition of the mesophyll, and the presence of epidermal papillae.

Culture media for the multiplication of wild Manihot species

ABSTRACT The cassava propagation system is slow and favors disease transmission through successive generations. Micropropagation is an alternative to overcome the aforementioned limitations, besides allowing the generation of a larger number of pest- and pathogen-free plants. Therefore, the aim of the present study is to investigate the effect of culture media on the multiplication in vitro of five wild Manihot species. The experiment followed a completely randomized design, at factorial arrangement 5 (wild Manihot species) x 6 (culture media), with 11 repetitions. Explants consisted in nodal segments (91 cm long and one lateral bud) of species Manihot flabellifolia, M. tristis, M. caerulescens, M. chlorosticta and M. jacobinensis, which were extracted in vitro from the collection of wild cassava species. One segment was placed in each test tube added with 10 mL of MS media 0.01, 17N, 12A3, 4E, 8S and WPM, and kept for 90 days in growth room under 30 μmol m-2 s-1irradiance, temperature 27 ± 1 °C and 16h photoperiod. Variables plant height (cm), number of green leaves, number of senescent leaves, number of shoots, number of microcuttings, fresh and dry shoot mass, fresh and dry root mass (mg) and callus mass (mg) were analyzed. Our results showed that the culture medium 12A3 was not responsive to any of the species; however, if one takes into consideration variables plant height and number of microcuttings, this medium can possibly be used in the micropropagation of other wild species belonging to genus Manihot.

Conservation assessment of cassava wild relatives in central Brazil

Crop wild relatives (CWR) are a key component of the world’s biota since they have the potential to contribute traits for crop improvement. The rich flora of the Brazilian Cerrado harbours a large number of CWR, but little is known about their distribution and conservation status. This study focused on the conservation of cassava (Manihot) wild relatives in the Cerrado. To accomplish this, we performed herbarium and field surveys to assess species conservation status based on geographic distribution, population density estimates, and rates of habitat loss. We found 75 species of Manihot occurring in the Cerrado, including 59 endemics. Among the endemic taxa, 24 are at some level of threat according to IUCN classification (14% Vulnerable, 22% Endangered, 5% Critically endangered), mostly owing to narrow geographic range and habitat loss. Most species are locally abundant, ranging from 55 to 1493 mature individuals per hectare. A quarter of the species recorded have been described over the past 5 years, indicating that the diversity of Manihot in the Cerrado is still underestimated. Areas of high species richness and endemism coincided mostly with Cerrado highlands, particularly in northern Goias state. Field surveys in 16 reserves indicate that 54% of Cerrado endemics are not represented in these protected areas. We believe that the patterns of distribution and conservation status uncovered here for Manihot are representative of many plant groups that are particularly diverse in high-altitude areas in the Cerrado. This calls for expansion of the network of protected areas to cover a wider range of environments, particularly those with a concentration of rare and endemic species, to ensure the effective in situ conservation of CWR present in the Cerrado flora.

Manioc starch thin film as support of reduced graphene oxide: A novel architecture for electrochemical sensors

The manioc starch (MS) product extracted of many Manihot species, presents low cost and film formation capability. In this work, we report the decoration of MS thin film with reduced graphene oxide to form a novel composite, which we used to modify a glassy carbon electrode for phenolic compounds detection. The characterization of the nanostructured biopolymeric film was performed by scanning electron and atomic force microscopy, electrochemical impedance, ultraviolet-visible and Fourier transform infrared spectroscopies, dynamic light scattering and cyclic voltammetry techniques. Under optimal experimental conditions, the peak currents were independently studied in the concentration range of 0.5 to 200 μmol L−1 and 0.5 to 74 μmol L−1 with a limit of detection of 0.07 μmol L−1 and 0.04 μmol L−1, for dopamine and catechol, respectively, as proof of concept. MS proved to be a great asset for supporting thin film for electroanalytical devices, which were tested in water and synthetic urine samples, with satisfactory results.