Tropical Root Research Articles

A Review of Tropical Root and Tuber Crops for Livelihood Security and Nutrition

Root and tuber crops (RTCs) are an essential source of food for many developing and underdeveloped countries, providing a substantial part of the world’s food supply. With the global population projected to reach 9.8 billion by 2050, the importance of RTCs is likely to increase. These crops are not only a cheap source of food and energy but also exhibit high biological efficiency and can withstand biotic and abiotic challenges. RTCs namely sweet potato, cassava, yams, and taro are rich in nutrients. The bioactive compounds present in these crops have been shown to have medicinal properties. The glutin free, and low glycemic indices of RTCs make them suitable foods for celiac and diabetic patients. These crops are able to grow under different climatic conditions and fit well with different cropping systems for year-round production and employment generation in lower economic populace. This review highlights the importance of RTCs as a sustainable food and industrial corps and their potential to alleviate malnutrition and improve public health.

Water and Irrigation Needs of Tuber Crops in Coastal Climates: A Review

One of the most essential elements for plant growth is water. Large amounts of it are required by plants constantly throughout their life cycle. It significantly affects agricultural activities like irrigation, soil management, crop production, and chemical spraying environments, as well as plant processes like photosynthesis, respiration, absorption, transport, and use of mineral nutrients. This review examines the impacts of climate change on root and tuber crops, including rising temperatures, altered rainfall patterns, extreme weather events, and changes in pest and disease dynamics. These changes significantly affect root and tuber crop production, leading to lower yields, compromised quality, increased susceptibility to pests and diseases, and limited access to water resources. Adaptation strategies encompass various approaches, such as agronomic practices, crop diversification, improved water management, breeding for climate resilience, and agro ecological methods. In the world, the most significant root and tuber crops are cassava, sweet potatoes, and potatoes. Water will produce maximum production for root crops; however, water stress during critical stages might adversely affect the final output of root crops. The purpose of this article of review is to understand the water and irrigation needs of tuber crops (sweet potato, greater and lesser yams, aerial yams, elephant foot yams, xanthosoma, and cassava) that are effectively produced in Maharashtra's coastal climate. This review emphasizes the urgent need to address climate change impacts on tropical root and tuber crops. It highlights the critical role of adaptive measures in ensuring long-term sustainability and food security in a changing climate.

Women in Cassava Processing and Marketing in North Central Nigeria: Are they any Happier?

Cassava is one of the most important staple food items available in Nigeria. Nigeria is the largest producer of cassava and it’s considered the most important tropical root crop providing food and income to over 30 million farmers, processors and traders. The objective of this study is to ascertain the happiness status of women combining occupation of processing and marketing cassava with family responsibility in north-central Nigeria. This objective is motivated by novelty of such researches in the research area. The findings revealed that women in processing and marketing of cassava in north central Nigeria are happy. The study concludes that happiness question in the study area is influence by the people’s culture where one will hardly said he/she is unhappy. The study therefore, recommends that community leaders and local government authorities encourage women in cassava processing and marketing to always form cooperative societies. This will not only make them a formidable common front but will improve their contributions/supports to families from their cooperatives pool resources.

Tropical root responses to global changes: A synthesis.

Tropical ecosystems face escalating global change. These shifts can disrupt tropical forests' carbon (C) balance and impact root dynamics. Since roots perform essential functions such as resource acquisition and tissue protection, root responses can inform about the strategies and vulnerabilities of ecosystems facing present and future global changes. However, root trait dynamics are poorly understood, especially in tropical ecosystems. We analyzed existing research on tropical root responses to key global change drivers: warming, drought, flooding, cyclones, nitrogen (N) deposition, elevated (e) CO2, and fires. Based on tree species- and community-level literature, we obtained 266 root trait observations from 93 studies across 24 tropical countries. We found differences in the proportion of root responsiveness to global change among different global change drivers but not among root categories. In particular, we observed that tropical root systems responded to warming and eCO2 by increasing root biomass in species-scale studies. Drought increased the root: shoot ratio with no change in root biomass, indicating a decline in aboveground biomass. Despite N deposition being the most studied global change driver, it had some of the most variable effects on root characteristics, with few predictable responses. Episodic disturbances such as cyclones, fires, and flooding consistently resulted in a change in root trait expressions, with cyclones and fires increasing root production, potentially due to shifts in plant community and nutrient inputs, while flooding changed plant regulatory metabolisms due to low oxygen conditions. The data available to date clearly show that tropical forest root characteristics and dynamics are responding to global change, although in ways that are not always predictable. This synthesis indicates the need for replicated studies across root characteristics at species and community scales under different global change factors.

The degree of a tropical root surface of type A

The degree of a tropical root surface of type A

Pedological Investigation of Soil Quality Indicators in Tapioca Growing Soils

Background: Manihot esculenta, the most important tropical root crop which supply dietary staple food for about 800 million populations worldwide. Twenty soil profiles that represent the soil Pedology and soil quality are similar in their concept in relation to soil formation. In this regards, soil quality can be considered as part of the science of pedology. Significant differences in yield of Tapioca (Manihot esculenta) with selected soil properties and subsequent interpretations as influenced by land use are explained. Methods: Soil samples were taken from designated pedogenic horizons for physico-chemical properties in the laboratory. Soil textural class, saturated hydraulic conductivity, Cation Exchange Capacity, Base Saturation Percentage, soil organic carbon, exchangeable cations, available N, P, K content and available micronutrients were analysed. The general fertility of the soils in the area is discussed highlighting their potentials and constraints. Result: A comprehensive analysis of soils in the study area showed that shallow soil depth of less than 47 cm and more clay of 44% with high bulk density of 1.4 gcc-1, low hydraulic conductivity of 0.12 cmhr-1, low base saturation percentage of 77%, more exchangeable sodium percentage of 7.96% with low available N, P and K of 110, 10.75 and 142.25 kg ha-1, respectively in low yielding soils are the major constraints in the tract might behind the yield differences in Cassava.

Haplotype-resolved genome of heterozygous African cassava cultivar TMEB117 (Manihot esculenta)

Cassava (Manihot esculenta Crantz) is a vital tropical root crop providing essential dietary energy to over 800 million people in tropical and subtropical regions. As a climate-resilient crop, its significance grows as the human population expands. However, yield improvement faces challenges from biotic and abiotic stress and limited breeding. Advanced sequencing and assembly techniques enabled the generation of a highly accurate, nearly complete, haplotype-resolved genome of the African cassava cultivar TMEB117. It is the most accurate cassava genome sequence to date with a base-level accuracy of QV > 64, N50 > 35 Mbp, and 98.9% BUSCO completeness. Over 60% of the genome comprises repetitive elements. We predicted over 45,000 gene models for both haplotypes. This achievement offers valuable insights into the heterozygosity genome organization of the cassava genome, with improved accuracy, completeness, and phased genomes. Due to its high susceptibility to African Cassava Mosaic Virus (ACMV) infections compared to other cassava varieties, TMEB117 provides an ideal reference for studying virus resistance mechanisms, including epigenetic variations and smallRNA expressions.

Expected yield and economic improvements of a yam seed system in West Africa using agro‐physiological modelling

Societal Impact StatementYam is a major tropical root crop and a staple food for millions of people in West Africa. The model used in this study shows that promoting the use of improved seed tubers would help increase yields and profitability for farmers. This could lead to improved food security, increased income and higher standards of living. Additionally, the model serves as a useful decision‐support tool for farmers and technicians to choose, depending on the species, the optimum seed‐tuber weight and planting date. This study provides agronomic arguments to justify investments in the improvement of yam planting materials in West Africa.Summary Yam (Dioscorea spp.) is a major tropical root crop, grown mainly in West Africa using traditional extensive techniques. Farmers typically reuse seed tubers by setting aside up to 30% of their production for the next season, leading to high planting material variability that affects yields. Several initiatives aim to promote the use of improved seed tubers. However, to help their adoption, it is necessary to quantify the agronomic and economic advantages. To address this, a model for individual plant growth and development was developed based on six experiments in Benin from 2007 to 2009. This model simulates the combined effect of emergence (through photoperiod and temperature) and seed‐tuber weight on yam plant growth and development. Its predictions were highly correlated with observed plant tuber yield (R2 > 0.83). Results highlight the crucial role of key processes such as seed‐tuber physiological age and photoperiod sensitivity. The study shows that for the traditional planting dates, the use of improved planting material could lead to a yield increase of 22%–27% and a gain in profitability of 30% and 40% for Dioscorea alata and Dioscorea rotundata, respectively. The model proved to be a useful decision‐support tool for choosing an optimum seed‐tuber weight, depending on the species and the planting date. This study validates investments in yam seed systems in West Africa. However, beyond seed size and health, other factors such as dormancy, storage time and their management need to be considered to address emergence heterogeneity and its impact on yield.

Climate change impacts on tuber crops: vulnerabilities and adaptation strategies

Climate change poses significant challenges to root and tuber crops, requiring robust adaptation strategies to mitigate vulnerabilities. This review examines the impacts of climate change on root and tuber crops, including rising temperatures, altered rainfall patterns, extreme weather events, and changes in pest and disease dynamics. These changes significantly affect root and tuber crop production, leading to lower yields, compromised quality, increased susceptibility to pests and diseases, and limited access to water resources. Adaptation strategies encompass various approaches, such as agronomic practices, crop diversification, improved water management, breeding for climate resilience, and agroecological methods. However, addressing knowledge gaps and research needs is crucial for better-understanding climate change impacts and developing effective adaptation strategies for root and tuber crops. Future research should prioritize resilient cultivar identification, enhanced cropping systems, improved pest and disease management, and exploring socio-economic dimensions of adaptation. This review emphasizes the urgent need to address climate change impacts on tropical root and tuber crops. It highlights the critical role of adaptive measures in ensuring long-term sustainability and food security in a changing climate

Characterization of open chromatin in response to cold reveals transcription factor association with preferred binding distances in cassava

Cassava is a tropical root crop that is sensitive to low temperature. While the transcriptome for cold-responsive genes has been extensively studied, information on their regulation is largely unavailable. Here, we conducted assays of plant morphology, the transcriptome, and open chromatin in cassava under moderate cold stress (10 ℃). We observed reversible morphological changes in cassava plants under continuous cold stress, in which plants showed wilting of the apical leaf blade and petiole at 5 h and recovery at 48 h. Consistently, distinct expressional dynamics for genes in response to cold were detected at 5 h and 48 h in both tissues. We examined the genome-wide DNase I-hypersensitive sites (DHSs) and their dynamics using cold-treated leaf blades and petioles. We revealed that cold-induced DHSs (coiDHSs) substantially differed among tissues and treatments. However, the putative coiDHS-derived transcription factors (TFs) largely co-occurred across tissues and treatments, and 61 TFs commonly shared by all samples were isolated. A putative functional network with 30 interconnected TFs was created. The frequent empirical interactions among these TFs indicate their roles in the cold response. Notably, we found that the two pairs of known cold-responsive TFs AGL20-RGA and ERF5-ERF105 showed highly frequent co-occurrence in coiDHSs. Moreover, the binding-site distances differed among TF pairs or samples, indicating that there are preferred distances between cooperative TFs and that such distances may depend on biological conditions. The identification of conserved TFs and their cooperativity provides valuable information for elucidating the transcriptional networks underlying cold gene expression in cassava.

Weak phylogenetic and habitat effects on root trait variation of 218 Neotropical tree species

IntroductionTropical forests harbor a large diversity of closely related tree species that can thrive across habitats. This biodiversity has been found to correspond to large functional diversity in aboveground traits, and likely also relates to belowground trait variation. Globally, root trait (co-)variation is driven by different belowground resource strategies of species, environmental variation, and phylogeny; however, these patterns mostly reflect observations from temperate biomes and remain unconfirmed in tropical trees. We examine phylogenetic and environmental effects on root trait (co-)variation of trees across habitats in an Amazonian rainforest.MethodsRoots of 218 tree species from ten dominant families were sampled across three major habitats near Manaus, Brazil. We quantified five morphological and architectural root traits to (i) investigate how they reflected different resource strategies across species, (ii) compare them between families and superorders to test phylogenetic effects, and (iii) compare them between habitats to determine environmental effects on root trait expressions and variability.ResultsRoot traits discriminated species along a tradeoff between root diameter and root branching and, secondly, due to variation in root tissue density. Our results further show weak phylogenetic effects on tropical tree root variation, for example, families from the same superorder showed large divergence in their root traits, while those from different superorders often overlapped in their root morphology and architecture. Root traits differed significantly between habitats but habitat type had only little effect on overall root trait variation.DiscussionOur work suggests that the dimensions and drivers that underlie (co-)variation in tropical root traits may differ from global patterns defined by mostly temperate datasets. Due to (a)biotic environmental differences, different root trait dimensions may underlie the belowground functional diversity in (Neo)tropical forests, and we found little evidence for the strong phylogenetic conservatism observed in root traits in temperate biomes. We highlight important avenues for future research on tropical roots in order to determine the degree of, and shifts in functional diversity belowground as communities and environments change in tropical forests.

Future climate suitability of underutilized tropical tuber crops-‘Aroids’ in India

Elephant foot yam and taro are the two important aroids of tropical tuber crops, considered as underutilized in the context of climate change and food security. The present study focused to quantify the future climate suitability of aroids for future climate scenarios 2030, 2050, and 2070 for the two representative concentration pathways (RCP 4.5 and RCP 8.5). The district-wise future climate suitability of elephant foot yam and taro using MaxEnt across India was quantified. The percentage increase in climatically suitable area for taro is 49% and the same for elephant foot yam is 46% which is higher compared to those of tropical root crops. A total of 218 districts were identified as highly suitable for the cultivation of elephant foot yam for different RCPs across India. A total of 209 districts were observed as highly suitable for taro cultivation across India for the two RCPs. The information about the districtlevel suitability can assist decision-makers to understand the possible shifts in the climate suitability of aroids in India in the context of food security as they have higher productivity compared to other major food grain crops.

Isolation and Identification of Fungi Associated with the Spoilage of Cocoyam Corms

Cocoyam (Colocasia esculenta) is an important tropical root crop grown purposely for its starchy corms. This study was carried out to isolate and identify fungi associated with the spoilage of cocoyam corms. These organisms were isolated from spoilt corms by direct inoculation of the rotten tissues on Sabouraud Dextrose Agar. The fungal isolates were identified using cultural and morphological features such as colony appearance and also through microscopic characteristics. The isolated organisms include Rhizopus stolonifera, Rhizopus arrhizus, Fusarium oxysporum, and Aspergillus niger. Out of the 70 samples that were analyzed, 45 (64%) had Rhizopus stolonifera, 36 (51%) had Fusarium oxysporum, 52 (74%) had Rhizopus arrhizus while 61 (87%) had Aspergillus niger. A pathogenicity test was carried out on healthy corms using isolated microorganisms. The result showed that the organisms were responsible for the deterioration of the corms. These organisms may have infected these corms through contaminated working tools during harvest or improper storage by farmers. Corms are always infected by molds if not properly handled or stored. Hence, proper care should be taken while harvesting, handling, or storing these corms to avoid being infected by these pathogenic organisms since they can be detrimental to human health. It can also cause huge economic losses to farmers.

In Vitro Plant Response of Taro cv. ‘INIVIT MC- 2012’ (Colocasia Esculenta (L.) Schott) to Water Stress Induced with Polyethylene Glycol 6000

Modern Concepts & Developments in Agronomy In Vitro Plant Response of Taro cv. ‘INIVIT MC- 2012’ (Colocasia Esculenta (L.) Schott) to Water Stress Induced with Polyethylene Glycol 6000 Arletys Santos Pino*, Jorge López Torres, Aymé Rayas Cabrera and Víctor Medero Vega Division of Plant Biotechnology, Cuba *Corresponding author:Arletys Santos Pino, Associate Researcher, Division of Plant Biotechnology. Research Institute of Tropical Root and Tubers Crops, Santo Domingo, Villa Clara, Cuba Submission: September 12, 2022;Published: December 02, 2022 DOI: 10.31031/MCDA.2022.12.000779 ISSN 2637-7659Volume12 Issue 1

Climate change and cocoyam (Colocasia esculenta (L.) Schott) production: assessing impacts and potential adaptation strategies in Zimbabwe

Tropical root and tuber crops such as cocoyam (Colocasia esculenta (L.)) are important for food security and livelihoods and yet neglected in climate change impact studies and large-scale crop improvement programs. The aim of this study was to apply the maximum entropy modelling approach to assess production potential for the orphan crop cocoyam under current and projected climatic conditions by 2050 and 2070 in Zimbabwe. A robust model fit was achieved (AUC > 0.9) with variable importance showing that precipitation-related factors were most important in determining the suitability of cocoyam. About 4.3% of the country is suitable for cocoyam production in Zimbabwe under current climatic conditions with the most suitable areas in eastern districts of Chipinge, Chimanimani, Mutare, Mutasa, Nyanga and Makoni. By 2050, model means project a decrease of 6%, 9%, 10% and 15% under RCP2.6, RCP4.5, RCP6.0 and RCP8.5, respectively. More drastic decreases are projected by 2070 with almost a quarter (23%) of the current suitable areas having lost their suitability for cocoyam production. There is a general model agreement in the direction of impacts except for RCP2.6 where CCSM4 model projects increases in suitability for cocoyam in the country while other models project decreases. We find that regulating canopy microclimate variation increases potential for cocoyam production under climate change and can be implemented to ensure resilience of cocoyam production systems. Therefore, stabilizing or improving orphan crops systems will substantially contribute to local food security and reduction of malnutrition especially during the lean season.

Modification of the existing maximum residue level for apricots and setting of import tolerances for cyantraniliprole in various crops.

In accordance with Article 6 of Regulation (EC) No 396/2005, the applicants FMC International and Syngenta Crop Protection submitted two requests to the competent national authority in France, respectively, to set import tolerances for the active substance cyantraniliprole in various crops and to modify the existing maximum residue levels (MRLs) in apricots. The data submitted in support of the requests were found sufficient to derive MRL proposals for apricots, potatoes, tropical root and tuber vegetables, cucurbits (inedible peel), lettuces and salad plants, Chinese cabbage and other leafy brassica (except kale), spinaches and similar leaves (except spinach), parsley and minor oilseeds. Based on the risk assessment results, EFSA concluded that the dietary intake of residues resulting from the uses of cyantraniliprole according to the reported agricultural practices is unlikely to present a risk to consumer health for the parent compound. A definitive conclusion on the risk for consumers cannot be derived for the degradation products IN‐N5M09 and IN‐F6L99 which are formed during cooking/boiling. For both compounds, the concerns on genotoxicity have been ruled out, but the general toxicity has not been addressed. The indicative exposure calculated by the EMS and EFSA for these compounds is affected by non‐standard uncertainties but can support risk managers to take an informed decision on the requested modification of the existing MRLs for the crops under assessment.

Tropical root-and tuber crops-based cropping systems — A review

Multiple cropping is the best way of sustainable intensification of crop production, from the limited resources. More flexibility in planting and harvesting of tropical root and tuber crops provide ample scope for various crop production systems. Intercropping of legumes, cereals, and vegetables in root and tuber crops increased system productivity with land-use efficiency, though yields of sole crop of roots and tubers decreased. Intercropping root and tuber crops in plantation and fruit tree crops gave additional returns. Weed suppression, pest and disease reduction and improvement in soil nutrient status are the additional benefits of root and tuber crops involved in multiple cropping systems. In rice (Oryza sativa L.)-based cropping system in the coastal plains of Odisha, West Bengal, Karnataka, Tamil Nadu and Andhra Pradesh, sweet potato (Ipomoea batatas L. Lam.) is planted after harvesting of rice to take advantage of the residual soil moisture and fertilizers. Multiple cropping also reduces severity of pests and diseases. The climate smart root and tuber crops generate assured income under various cropping systems.

RXam2, a NLR from cassava (Manihot esculenta) contributes partially to the quantitative resistance to Xanthomonas phaseoli pv. manihotis.

The overexpression of RXam2, a cassava NLR (nucleotide-binding leucine-rich repeat) gene, by stable transformation and gene expression induction mediated by dTALEs, reduce cassava bacterial blight symptoms. Cassava (Manihot esculenta) is a tropical root crop affected by different pathogens including Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of cassava bacterial blight (CBB). Previous studies have reported resistance to CBB as a quantitative and polygenic character. This study sought to validate the functional role of a NLR (nucleotide-binding leucine-rich repeat) associated with a QTL to Xpm strain CIO151 called RXam2. Transgenic cassava plants overexpressing RXam2 were generated and analyzed. Plants overexpressing RXam2 showed a reduction in bacterial growth to Xpm strains CIO151, 232 and 226. In addition, designer TALEs (dTALEs) were developed to specifically bind to the RXam2 promoter region. The Xpm strain transformed with dTALEs allowed the induction of the RXam2 gene expression after inoculation in cassava plants and was associated with a diminution in CBB symptoms. These findings suggest that RXam2 contributes to the understanding of the molecular basis of quantitative disease resistance.

Impact of climate change on the yield of tropical root and tuber crops vs. rice and potato in India

Impact of climate change on the yield of tropical root and tuber crops vs. rice and potato in India

Novel fructooligosaccharides of Dioscorea alata L. tuber have prebiotic potentialities

Dioscorea alata L. (Dioscoreaceae), commonly known as water yam, is a popular tuber crop vegetable used across the globe. It is mainly composed of starch (75–84% of the dry weight) with a small amount of proteins, lipids, and vitamins and is very rich in minerals. It has nutritional superiority compared with other tropical root crops. The main aim of the study was to extract and characterize the fructooligosaccharides (FOSs) fractions from the tuber of this plant and evaluate their prebiotic properties. The soluble FOSs were fractionated by the conventional solid-phase extraction method and were characterized by FT-IR, HPTLC, and ESI–MS analyses. In addition, the beneficial health attributes of these fractions were checked for in vitro and in vivo prebiotic properties in Swiss albino mice. The FT-IR, HPTLC, and ESI–MS analyses of the FOSs from the hot water and 80% ethanol fractions showed that both are rich in inulin-like prebiotics. Furthermore, these FOSs showed an excellent prebiotic activity score and had enhanced in vitro cholesterol-binding activities in the presence of probiotic lactic acid bacteria (LAB) strains. Moreover, these had good antioxidant efficacies with IC50 values of 36.51 µg/ml and 33.12 µg/ml. In vivo treatment in Swiss albino mice, these FOSs had significantly lowered serum cholesterol (df = 6, p value < 2.2e−16), serum HDL (df = 6, p value = 3.68e−11), serum LDL (df = 6, p value < 2e−16), serum VLDL (df = 6, p value = 2.2e−13), serum triglycerides (df = 6, p value < 2e−16), blood sugar (df = 6, p value = 0.01857), serum glutamic pyruvic transaminase (S.G.P.T., df = 6, p value = 0.01189), serum glutamic oxaloacetic transaminase (S.G.O.T., df = 6, p value = 0.01239) but no significant difference found in weight gain (df = 6, p value = 0.166) and serum creatinine (df = 6, p value = 0.987). Furthermore, they enhanced IgA-mediated immunomodulation and influenced the gut colonization of probiotic LAB strains than the standard prebiotics, inulin. Thus, the study revealed that the FOSs from the storage tuber of D. alata possess some novel prebiotic that could contribute to human nutrition. This is the first report of the prebiotic FOS characterization from this plant.