Cassava Cultivars Research Articles

In-vitro effects of sucrose and ascorbic acid on induction and shelf-life of micro-tuber of cassava (Manihot esculenta Crantz) genotypes

Background: Cassava production faces threat from postharvest physiological deterioration (PPD). The PPD is usually observed within the first 72 hours of harvest. Therefore, extending the shelf-life of cassava root-tubers by few days could reduce appreciable financial losses. Objective: This study is aimed to investigate effects of sucrose and ascorbic acid on induction and shelf-life of micro-tubers of cassava cultivars using an In-vitro model. Method: Effect of sucrose (30, 45, 60, 75 and 90 g/L) on the micro-tuber induction was determined after 45 days in these cultivars (TME 1333 and TME 2060). The optimal level was later combined with ascorbic acid (0, 25, 50, 75 and 100 mg/L) to investigate its effect on micro-tubers shelf-life during a 10-day storage. Each study was laid out in factorial under CRD with 5 replications. Results: The 30 g/L sucrose (control) produced the utmost number of micro-tubers (4.33), highest length (6.68 cm), and fresh weight (0.1495 g). The cultivar ‘TME 2060’ had longer (5.26 cm) and higher fresh weight (0.1079 g) than ‘TME 1333’ with 5.04 cm and 0.0977 g respectively. Ascorbic acid (100 mg/L) significantly delayed the discolouration of micro-tubers over a 10-day storage. Also, the 100 mg/L ascorbic acid produced the least percentage of deteriorated micro-tubers. Conclusion: Results demonstrate the roles of sucrose and ascorbic acid in micro-tuber formation and antioxidant activity in delaying PPD. Therefore, we propose for In-situ production (via breeding strategy) of vitamin C-fortified cassava varieties in order to control the incidence of PPD and in turn improve farmer`s economy.

Identification of cassava black stem and root rot agents in Thailand

Cassava (Manihot esculenta Crantz) black stem and root rot (BSRR) caused by complex fungi is one of the most serious fungal disease of cassava in Thailand. The objective of this study was to identify the causal agent of BSRR disease of cassava in Nakhon Ratchasima province, Thailand. From June 2015 to May 2018, the outbreak areas in three districts of Nakhon Ratchasima province were surveyed for cassava plants with the characteristic symptoms. From 1800 diseased samples, 139 fungal pathogens were isolated and separated by morphological traits. Among them, 33 fungal isolates were subsequently tested for pathogenicity on detached stems and roots of CMR 43-08-89, a susceptible cassava cultivar, and proved to be pathogenic with different levels of aggressiveness. Next, PCR amplification of DNA of eight pathogenic isolates with high aggressiveness using two sets of universal primers ITS1/ITS4 and Ef1-688F/Ef1-1251R, revealed that the TEF1-α gene region could be used for the identification and classification at the species level. The analysis results fit well with that of the morphological studies on growth and colonial characteristics of the eight isolates. Based on the GenBank database, they were identified as Lasiodiplodia theobromae, L. euphorbiaceicola and Neoscytalidium dimidiatum.

A method for rapid and homogenous initiation of post-harvest physiological deterioration in cassava storage roots identifies Indonesian cultivars with improved shelf-life performance

Cassava is the most cultivated and consumed root crop in the world. One of the major constraints to the cassava value chain is the short shelf life of cassava storage roots which is primarily due to the so-called post-harvest physiological deterioration (PPD). The identification of natural sources of PPD tolerance represents a key approach to mitigating PPD losses by generating farmer- and industry-preferred cassava cultivars with prolonged shelf life. In the present study, a PPD assessment method was developed to screen for PPD tolerance in the cassava germplasm. The proposed PPD assessment method displayed a reduced rate of microbial infection and allowed a rapid and homogenous development of typical PPD symptoms in the cassava storage roots. We successfully used the PPD assessment method in combination with an image-based PPD scoring method to identify and characterize PPD tolerance in 28 cassava cultivars from the Indonesian cassava germplasm. Our analysis showed a significant and positive correlation between PPD score and dry matter content (r = 0.589–0.664, p-value < 0.001). Analysis of additional root parameters showed a significant and positive correlation between PPD scores at 2 days post-harvest (dph) and root length (r = 0.388, p-value < 0.05). Our analysis identified at least 4 cultivars displaying a significantly delayed onset of PPD symptoms as compared to the other selected cultivars. The availability of cassava cultivars contrasting for tolerance to PPD will be particularly instrumental to understanding the molecular mechanisms associated with delayed PPD in cassava roots.

Flavonoid accumulation modulates the responses of cassava tuberous roots to postharvest physiological deterioration

Postharvest physiological deterioration (PPD) caused by wounding is one of the main constraints that affect the development of cassava industry. However, the molecular mechanisms underlying the PPD are unknown. In the present study the adaptive response to wound stress was analyzed in combination with transcriptome and metabolome in four kinds of PPD phenomenon from cassava tuberous roots. The results indicated that starch, β-carotene, (-)-epigallocatechin, cyanidin-3-O-glucoside, and L-epicatechin were altered in the wounded tuberous roots. Moreover, the ROS scavenging system was activated at the PPD preliminary stage. Transcriptome analysis further showed that the strongly induced genes were mainly related to carbohydrate metabolism, signal transduction, and polyketide metabolism. Twenty-eight differentially expressed genes (DEGs) in the flavonoid pathway were preferably enriched. The relative quantitative analysis of seventeen genes demonstrated that they were responsive to PPD. Fifty-one differential flavonoid metabolites were detected in widely targeted metabolome profile, among which, luteolin, kaempferol, (-) epicatechin, phloretin, and naringenin were enhanced during PPD. The virus-induced gene silencing of MeCHS3 and MeANR showed that tuberous roots changed tolerance to PPD, and the total flavonoid and anthocyanin contents in leaves were changed. Therefore, the candidate genes and metabolites in flavonoid pathways could participate in PPD regulation. In addition, a proposed model was generated to elaborate the response mechanism of flavonoids under wounding stress, thus providing a future direction for breeding PPD-tolerant cultivars of cassava.

MePAL6 regulates lignin accumulation to shape cassava resistance against two-spotted spider mite.

The two-spotted spider mite (TSSM) is a devastating pest of cassava production in China. Lignin is considered as an important defensive barrier against pests and diseases, several genes participate in lignin biosynthesis, however, how these genes modulate lignin accumulation in cassava and shape TSSM-resistance is largely unknown. To fill this knowledge gap, while under TSSM infestation, the cassava lignin biosynthesis related genes were subjected to expression pattern analysis followed by family identification, and genes with significant induction were used for further function exploration. Most genes involved in lignin biosynthesis were up-regulated when the mite-resistant cassava cultivars were infested by TSSM, noticeably, the MePAL gene presented the most vigorous induction among these genes. Therefore, we paid more attention to dissect the function of MePAL gene during cassava-TSSM interaction. Gene family identification showed that there are 6 MePAL members identified in cassava genome, further phylogenetic analysis, gene duplication, cis-elements and conserved motif prediction speculated that these genes may probably contribute to biotic stress responses in cassava. The transcription profile of the 6 MePAL genes in TSSM-resistant cassava cultivar SC9 indicated a universal up-regulation pattern. To further elucidate the potential correlation between MePAL expression and TSSM-resistance, the most strongly induced gene MePAL6 were silenced using virus-induced gene silencing (VIGS) assay, we found that silencing of MePAL6 in SC9 not only simultaneously suppressed the expression of other lignin biosynthesis genes such as 4-coumarate--CoA ligase (4CL), hydroxycinnamoyltransferase (HCT) and cinnamoyl-CoA reductase (CCR), but also resulted in decrease of lignin content. Ultimately, the suppression of MePAL6 in SC9 can lead to significant deterioration of TSSM-resistance. This study accurately identified MePAL6 as critical genes in conferring cassava resistance to TSSM, which could be considered as promising marker gene for evaluating cassava resistance to insect pest.

Evaluation of improved cassava (Manihot esculenta Crantz) varieties and associated products for proximate, cyanogenic potential and glycemic indices

ABSTRACT This study investigated the proximate, cyanide, and glycemic indices of roots and eba (gari dough) made from improved cassava cultivars. Twenty cassava cultivars were obtained from the IITA research farms and analyzed for proximate and carbohydrate compositions and cyanogenic potential using standard procedures. Afterward, four cassava varieties were selected using the agglomerate hierarchical cluster analysis. The selected varieties were processed into gari and reconstituted in hot water into eba, and the glycemic indices(GIs) of the four eba samples were determined in apparently 23 healthy volunteers. The starch content of the selected varieties was 69.1% for IITATMEB7419, 71.6% for TMSIBA980505, 72.7% for TMSIBA981089A, and 74.5% for TMSIBA980002. The ratios of starch to sugar were significantly (p > 0.05) comparable for all the samples. The GIs obtained for the four eba samples were 88.1% for TMSIBA980002; 87.2% for TMS980505; 84.4% for TMEB7419, and 89.1% for TMS IBA961089A.

BRS Progresso and BRS Rendeira - new cassava cultivars with tolerance to post-harvest deterioration

BRS Progresso and BRS Rendeira - new cassava cultivars with tolerance to post-harvest deterioration

Influence of Harvest Periods on Cassava (&amp;lt;i&amp;gt;Manihot esculenta&amp;lt;/i&amp;gt; Crantz) Agronomic Traits and Physiological Response to Post-Harvest Physiological Deterioration

Cassava (Manihot esculenta Crantz) is the third largest source of calories in tropical countries and the sixth most important food crop in the World. However, the short shelf life of its storage roots after harvest due to a rapid post-harvest physiological deterioration (PPD) makes the roots to be considered as a risky product to market. The objectives of this work were to investigate the influence of two harvest periods on cassava agronomic parameters and their physiological response to PPD. Three cassava cultivars 96/1414, I070593 and LMR were selected for the experiment and harvested at 10 and 12 months after planting (MAP). The response to PPD was assessed during storage at 0, 3, 8 and 15 days after harvest (DAH). Total proteins content, soluble sugars and starch, total polyphenols compounds, polyphenoloxidase and peroxidase activities were recorded during storage. Results showed large variation among the parameters at the two harvest periods across the cultivars. High number of tubers was recorded in all the cultivars at 12 MAP and a significant increase in storage roots length was observed in 96/1414 and LMR from 10 MAP to 12 MAP (25 ± 5.1 to 41.3 ± 5.9 and 22.6 ± 3.3 to 27.9 ± 4.8) respectively. A reduction of about 49% of tubers weight was observed in I070593 from 10 to 12 MAP while an increase of about 36% and 11% were recorded in LMR and 96/1414 respectively. Tubers from I070593 showed less susceptibility to PPD when harvested at 10 MAP compared to those from LMR and 96/1414 where less susceptibility to PPD were recorded at 12 MAP. An increase in soluble sugars content, total proteins content and peroxidase activity subsequently to a decrease in starch content were recorded during storage from 8 to 15 days after harvest especially at 10 MAP in I070593 and at 12 MAP in LMR and 96/1414. High content of total phenolic compounds and less activity of polyphenol oxidase were correlated to PPD susceptibility. This work opens a new insight issue of the consideration of the appropriate harvest time of the cultivars as a tool to better control the onset of postharvest physiological deterioration.

Data Envelopment Analysis for identifying the most suitable cassava cultivar: A case study of various cultivated area in Thailand

Data Envelopment Analysis for identifying the most suitable cassava cultivar: A case study of various cultivated area in Thailand

Data envelopment analysis for identifying the most suitable cassava cultivar: a case study of various cultivated areas in Thailand

Data envelopment analysis for identifying the most suitable cassava cultivar: a case study of various cultivated areas in Thailand

Granular structure, physicochemical and rheological characteristics of starch from yellow cassava (Manihot esculenta) genotypes

ABSTRACT This study examined the structural and physicochemical characteristics of starch isolated from seven yellow cassava genotypes. The structural properties of yellow cassava starch from these cultivars were elucidated by scanning electron microscopy, X-ray diffractometry and Fourier Transformed Infrared Spectroscopy (FTIR). Their water interaction properties, digestibility and viscoelastic behavior were also compared, and principal component analysis was used to establish factors associated with the variability in properties of the starch. All the starches were of the A-type diffraction pattern, with crystallinity ranging between 31 and 37%. Most of the granules exhibited spherical and oval shapes, some with a flat surface on one side. They had smooth surfaces and their sizes ranged from 4 µm for round granules to 23 µm for the major axis of oval-shaped granules. Significant differences (p < .05) were observed in amylose content, in-vitro digestibility, peak and breakdown viscosity of the starches, and these ranged between 13.6–18.1%, 11.4–18.5%, 354–520 BU and 233–366 BU, respectively. Significant differences were also recorded in the hydration and textural behavior of starches from these cassava cultivars. The differences observed in granular and physicochemical properties are likely to influence the performance of these cassava cultivars in food applications.

AlcoR: alignment-free simulation, mapping, and visualization of low-complexity regions in biological data.

Low-complexity data analysis is the area that addresses the search and quantification of regions in sequences of elements that contain low-complexity or repetitive elements. For example, these can be tandem repeats, inverted repeats, homopolymer tails, GC-biased regions, similar genes, and hairpins, among many others. Identifying these regions is crucial because of their association with regulatory and structural characteristics. Moreover, their identification provides positional and quantity information where standard assembly methodologies face significant difficulties because of substantial higher depth coverage (mountains), ambiguous read mapping, or where sequencing or reconstruction defects may occur. However, the capability to distinguish low-complexity regions (LCRs) in genomic and proteomic sequences is a challenge that depends on the model's ability to find them automatically. Low-complexity patterns can be implicit through specific or combined sources, such as algorithmic or probabilistic, and recurring to different spatial distances-namely, local, medium, or distant associations. This article addresses the challenge of automatically modeling and distinguishing LCRs, providing a new method and tool (AlcoR) for efficient and accurate segmentation and visualization of these regions in genomic and proteomic sequences. The method enables the use of models with different memories, providing the ability to distinguish local from distant low-complexity patterns. The method is reference and alignment free, providing additional methodologies for testing, including a highly flexible simulation method for generating biological sequences (DNA or protein) with different complexity levels, sequence masking, and a visualization tool for automatic computation of the LCR maps into an ideogram style. We provide illustrative demonstrations using synthetic, nearly synthetic, and natural sequences showing the high efficiency and accuracy of AlcoR. As large-scale results, we use AlcoR to unprecedentedly provide a whole-chromosome low-complexity map of a recent complete human genome and the haplotype-resolved chromosome pairs of a heterozygous diploid African cassava cultivar. The AlcoR method provides the ability of fast sequence characterization through data complexity analysis, ideally for scenarios entangling the presence of new or unknown sequences. AlcoR is implemented in C language using multithreading to increase the computational speed, is flexible for multiple applications, and does not contain external dependencies. The tool accepts any sequence in FASTA format. The source code is freely provided at https://github.com/cobilab/alcor.

The Leaf Color and Trichome Density Influence the Whitefly Infestation in Different Cassava Cultivars.

The whitefly species Bemisia tuberculata and Aleurotrixus aepim (Hemiptera: Aleyrodidae) are considered important cassava (Manihot esculenta) pests. Leaf color and other morphological characteristics can influence the pest's interactions with the host plants. Thus, this study aimed to identify the relationship between whitefly occurrence and trichome density and leaf color in different cassava cultivars. The study was conducted in the field during the 2014/2015 and 2016/2017 crop seasons. The whitefly occurrence was surveyed in the cultivars, IAPAR 19, IPR Upira, IPR União, IAC 576-70, IAC 14, IAC 90, Catarina Branca, Santa Helena and Baianinha. The whitefly nymph quantification was correlated with non-glandular trichome density, luminosity (L*) and chroma (a* and b*) of the cassava leaves. IAPAR 19 and IAC 14 were less infested by whitefly nymphs when contrasted with IPR União, IPR Upira and Baianinha, which were the most infested. The lowest B. tuberculata infestations were correlated with lesser trichome density, highest light reflection and highest chroma in the sprout and the plant's superior third portion leaves. Low A. aepim infestation in both crop seasons made it impossible to verify its correlation with the studied cassava plant characteristics. The cultivars IAPAR 19 and IAC 14 could contribute towards B. tuberculata management in regions with a history of whitefly infestation.

Relationship between structure and functional properties of starch from different cassava (Manihot esculenta Crantz) and yam (Dioscorea opposita Thunb) cultivars used for food and industrial processing

This work investigated the functional properties of four varieties of yam starch and four varieties of cassava starch to better understand the relationship between the structure and properties of various forms of starch. The relationship between the functional properties and structure of starch was explored using Pearson correlation (PCs) and principal component analysis (PCA). The analyses demonstrated that yam starch and cassava starch differ significantly in structure and functional properties. Yam starches have a higher requirement during gelatinization, may hold a higher trough viscosity and final viscosity, and are easier to retrograde after gelatinization; this results in starch gels with a higher hardness and gel strength. While the cassava starches have a higher breakdown, their starch gels are fluid and squishy. The differences in starch functional properties were linked to particle size, short-range ordered structure, protein content, and average radius of gyration in PCs and PCA. The present investigation demonstrates a link between the functional properties of cassava and yam starch and their structural features and suggests that acceptable processing methods and applications for these tuber starches be selected based on their functional properties.

On-Farm Multi-Environment Evaluation of Selected Cassava (Manihot esculenta Crantz) Cultivars in South Africa.

Cassava is an important starchy root crop grown globally in tropical and subtropical regions. The ability of cassava to withstand difficult growing conditions and long-term storability underground makes it a resilient crop, contributing to food and nutrient security. This study was conducted to evaluate the performance and adaptability of exotic cassava cultivars across different environments in South Africa and to recommend genotypes for cultivation. A total of 11 cassava cultivars were evaluated at six on-farm sites, using a randomized complete block design with three replications. There were highly significant (p < 0.001) variations between genotypes, environments, and their interaction for all yield and yield-related traits studied. This indicates the need to test the genotypes in multiple environments before effective selection and commercialization can be undertaken. MSAF2 and UKF4 showed the overall best performances for most of the traits, whilst UKF9 (49.5%) and P1/19 (48.5%) had the highest dry matter yield. UKF4 (102.7 t ha−1) had the highest yield and greatest root yield stability across environments. MSAF2 did not perform consistently across environments because it was highly susceptible to cassava mosaic disease (CMD). MSAF2 could be used as a donor parent to generate novel clones with large numbers of marketable roots, and high fresh root yields, if the other parent can provide effective resistance to CMD. Based on genotype and environmental mean, Mabuyeni (KwaZulu-Natal), Mandlakazi (Limpopo), and Shatale (Mpumalanga) were found to be better environments for cassava cultivation and testing. This study is a pioneer in cassava research using multiple environments in South Africa. It provides baseline information on the performance of currently available cassava clones, their adaptation to multiple sites, the identification of suitable test sites, and information on current genetic resources for a future breeding program.

Acúmulo e eficiência do uso do fósforo em cultivares de mandioca irrigadas no semiárido brasileiro

ABSTRACT Phosphorus is of fundamental importance for the energy supply necessary for plant metabolism, but it is still understudied for important agricultural crops such as cassava. The objective of this study was to evaluate the accumulation and efficiency of phosphorus use in different cassava cultivars in the semiarid region. Two experiments were carried out during two agricultural seasons 2018/2019 and 2019/2020 in Mossoró, Rio Grande do Norte state, Brazil. The experimental design was randomized blocks, in split plots, with four replicates. In the plots, five doses of phosphorus (P) (0, 60, 120, 180, and 240 kg ha-1 of P2O5) were applied in the planting furrow, and four cassava cultivars (Água Morna, BRS Gema de Ovo, Recife, and Venâncio) were cultivated in the subplots. The cultivars Água Morna and Recife export more phosphorus through their roots. The cultivars Venâncio and Água Morna show greater agronomic efficiency when fertilized with 60 kg ha-1 of P2O5. The apparent P recovery efficiency presented the following order: ‘BRS Gema de Ovo’ &gt; ‘Água Morna’ &gt; ‘Venâncio’ &gt; ‘Recife’, with higher indices at the dose of 60 kg ha-1 of P2O5.

Plant regeneration from leaf mesophyll derived protoplasts of cassava (Manihot esculenta Crantz).

A high yield of isolated protoplast and reliable regeneration system are prerequisite for successful somatic hybridization and genome editing research. However, reproducible plant regeneration from protoplasts remains a bottleneck for many crops, including cassava. We evaluated several factors that influence isolation of viable protoplasts form leaf mesophyll, induction of embryogenic calli, and regeneration of plants in three cassava cultivars; Muchericheri, TMS60444 and Karibuni. A relatively higher protoplast yield was obtained with enzyme mixture containing 5 g/L Macerozyme and 10 g/L cellulase. Muchericheri recorded relatively higher protoplast yield of 20.50±0.50×106 whereas TMS60444 (10.25±0.25×106) had the least protoplast yield in 10 g/L cellulase and 4 g/L cellulase. Freshly isolated protoplast cells were plated on callus induction medium (CIM) solid medium containing MS basal salt, 60 g/L D-glucose, 30 g/L sucrose, B5 vitamins, 100 mg/L myo-inositol, 0.5 mg/L copper sulphate, 100 mg/L casein hydrolysate, 4.55 g/L mannitol, 0.1 g/L MES, 10 mg/L picloram and 3 g/L gelrite to induce protoplast growth and development. The three cultivars reached colony formation but no further development was observed in this culture method. Protoplast growth and development was further evaluated in suspension culture using varying cell densities (1, 2 and 3× 105 p/mL). Development with highest number of minicalli was observed in cell density of 3× 105 p/mL. Minicalli obtained were cultured on CIM supplemented with 10mg/L picloram. Callus induction was observed in all cell densities with the cultivars. Highest somatic embryogenesis was observed in 2× 105 p/ml while no somatic embryogenesis was observed in cell density of 1×105 p/mL. Somatic embryos were matured in EMM medium supplemented with 1 mg/L BAP, 0.02 mg/L NAA and 1.5 mg/L GA3 then germinated in hormone free medium for plant regeneration. This protocol which used simple mixture of commercial enzymes is highly reproducible and can be applied in biotechnology research on cassava.

Agrobacterium-mediated Genetic Transformation of Cassava.

The storage root crop cassava (Manihot esculenta Crantz) is predicted to remain central to future food and economic security for smallholder farming households and agricultural output in the tropics. Genetic improvement of cassava is required to meet changing farmer and consumer needs, evolving pests and diseases, and challenges presented by climate change. Transgenic and genome editing technologies offer significant potential for introducing desired traits into farmer-preferred varieties and breeding lines, and for studying the biology of this under-investigated crop species. A bottleneck in implementing genetic modification in this species has been access to robust methods for transformation of cassava cultivars and landraces. In this article, we provide a detailed protocol for Agrobacterium-mediated transformation of cassava and regeneration of genetically modified plants. Basic Protocol 1 describes how to establish and micropropagate in vitro cassava plantlets, and Alternate Protocol 1 details how to establish in vitro cultures from field or greenhouse cuttings. Basic Protocol 2 describes all steps necessary for genetic transformation in the model variety 60444, and Alternate Protocol 2 provides details for modifying this method for use with other cultivars. Finally, Basic Protocol 3 describes how to establish plants produced via Basic Protocol 2 and Alternate Protocol 2 in soil in a greenhouse. These methods have proven applications across more than a dozen genotypes and are capable of producing transgenic and gene-edited plants for experimental purposes, for testing under greenhouse and field conditions, and for development of plants suitable for subsequent regulatory approval and product deployment. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Establishment and propagation of in vitro cassava plantlets Alternate Protocol 1: Establishment of in vitro plants from field or greenhouse plants Basic Protocol 2: Genetic transformation of cassava variety 60444 Alternate Protocol 2: Genetic transformation of additional cultivars Basic Protocol 3: Establishment and growth of plants in the greenhouse.

Thermal, Pasting, and Hydration Properties of Flour from Novel Cassava Cultivars for Potential Applications in the Food Industry

Abstract Cassava root flours from five different cultivars (C-MSAF2, C-P4/10, C-P98/0505, C-P98/0002, and C-UKF8) were studied for their potential application in the food industry. Proximate composition, functional, thermal, and pasting properties were investigated. Cassava flours were high in carbohydrates (85-86%) and their amino acid profiles varied. Cultivars C-MSAF2, C-P98/0002, and C-UKF8 showed high protein content (5.06%), mineral content (2.36%), and the largest particle size (72.33 µm), respectively. Solubility of cassava flours decreased as temperatures increased, however, swelling power and water absorption capacity increased. C-MSAF2 showed the highest peak viscosity, breakdown viscosity, and shortest peak time. C-P98/0505 showed the highest final viscosity, the highest pasting temperature, and the longest peak time. Cassava flours studied are promising candidates for utilization in the baking industry, however, their incorporation into baked product formulations needs further investigation.

Chemical composition and morphophysiological responses of Manihot plants

Cassava (Manihot esculenta Crantz) is an important forage source for livestock, while wild cassavas (maniçoba and pornunça – Manihot sp.), native from Brazilian semi-arid have the potential to feed ruminants in drylands. We hypothesized that maniçoba and pornunça have a chemical composition and morphophysiological responses similar to cassava cultivars. Nine Manihot plants were evaluated, six wild cassava accessions (BGMS 20, BGMS 21, BGMS 22, BGMS 26, BGMS 79, and BGMS 102), pornunça (BGMS 24) and two cassava cultivars (gema-de-ovo [GO] and engana-ladrão [EL]). We evaluated two 6-month crop cycles under a completely randomized design with four replicates. The genotype BGMS 20 had higher shoot biomass than BGMS 24, BGMS 79, EL, and GO, as well as higher leaf mass than EL and GO. Photosynthesis, leaf temperature, stomatal conductance, and transpiration were similar among the genotypes (13.83 µmol.m-2.s-1, 29.90 ºC, 0.12 mol.m-2.s-1 and 2.75 mmol.m-2.s-1, respectively). EL had a shoot crude protein content higher than the others, except for BGMS 21 and BGMS 24. Genotypes did not differ concerning in situ and in vitro (dry matter (DM)) degradability and mineral composition. BGMS 24 had a higher number of leaves than the others, and BGMS 20 had taller plants than the other genotypes, except for BGMS 21 and BGMS 22. In vitro gas production was similar among the genotypes considering total carbohydrates. Wild cassava accessions showed shoot biomass, leaf mass physiological responses, and chemical composition compatible with cassava cultivars; therefore, they show potential as alternative forages for livestock.