Cassava Varieties Research Articles

Cultivation and Processing of Cimanggu Cassava Harvest Waste at SMK Negeri I Borong, East Manggarai Regency

Cassava is one of the agricultural crops that has been widely cultivated in the East Nusa Tenggara region. The cimanggu variety is a cassava variety that is quite tolerant to drought and can produce 80 tons/ha. Additionally, the cimanggu variety is one of the most suitable cassavas for mocaf production. The East Manggarai Regency area is one of the fertile regions in NTT suitable for cassava cultivation, especially Cimanggu cassava. This research aims to understand the cultivation techniques of Cimanggu cassava in the Borong area and the role of SMK Negeri I Borong as a region for planting Cimanggu cassava. In addition, to understand the waste processing techniques generated during the harvesting process of Cimanggu cassava. The data collection method used a qualitative approach with data collection through field observation techniques. The research results show that the cultivation of cimanggu cassava plants carried out by students of SMKN 1 Borong includes land preparation (soil loosening), preparation of cimanggu cassava seeds, planting methods, planting distance, fertilization, weeding, and harvesting. The waste from the harvest of cimanggu cassava, in the form of cassava leaves and cassava peels, is processed into fermented livestock feed for animals.

Advancements and strategies of genetic improvement in cassava (Manihot esculenta Crantz): from conventional to genomic approaches.

Cassava (Manihot esculenta Crantz) is a staple food of 800 million people in the tropical and subtropical regions of the world. Its industrial utilization for bioethanol, animal feed, and starch are still continuously expanding. It was not until the 1970s that significant scientific efforts were undertaken to improve cassava, despite its considerable economic and social significance. Shortening the breeding cycle and improving the breeding efficiency are always the focus of the cassava breeding study. In this review, we provide a global perspective on the current status of cassava germplasm resources and explore the diverse applications of cassava breeding methods from hybridization, polyploidy, and inbreeding to genomic selection and gene editing. Additionally, we overview at least six nearly complete cassava genome sequences established based on modern genomic techniques. These achievements have substantially supported the advancing of gene discovery and breeding of new cassava varieties. Furthermore, we provide a summary of the advancements in cassava's functional genomics, concentrating on important traits such as starch quality and content, dry matter content, tolerance to postharvest physiological deterioration, nutritional quality, and stress resistance. We also provide a comprehensive summary of the milestone events and key advancements in cassava genetic improvement over the past 50years. Finally, we put forward the perspective of developing genomic selection breeding model and super-hybrids of cassava through building inbreeding population and emphasize the generation of triploid cassavas, as well as using gene editing technology allowing cassava to be a tropical model plant to serve for basic biological research and molecular breeding.

Validation of KASP Markers Associated with Hydrogen Cyanide in Fresh Cassava Roots in Uganda Cassava Germplasm

Low hydrogen cyanide (HCN) concentration is a high-priority trait for cassava varieties targeting their fresh and dry product profiles. To be acceptable, varieties bred and developed for these market segments must meet international safety standards for maximum acceptable residual levels of cyanide in cassava food and food products. The discovery of molecular markers that co-segregate with low HCN has not yet resulted in widespread usage in marker-assisted selection (MAS) in breeding programs. To deploy these HCN markers in regular MAS, assessing their reliability in various genetic backgrounds is crucial. The aim of this study was to assess the predictive accuracy of trait specific markers for HCN. The study used six HCN kompetitive allele-specific polymerase chain reaction (KASP) markers that had previously been developed in a Brazilian population and verified in segregating West African cassava populations. For most markers used in the study, the average call rate was more than 91.7%. Three markers—snpME00404, snpME00405 and snpME00406—showed a significant co-segregation of genotypes with the HCN phenotype. On average, genotypes that carried at least one copy of the favourable allele had lower HCN scores. The proportion of phenotypic variance accounted for by the three most important markers was 14% (snpME00406), 17% (snpME00405) and 27% (snpME00404). The validation of identified HCN SNP-markers marks a significant step in their deployment to support selection and advancement decisions in cassava breeding programs.

Genome-wide association studies unveils the genetic basis of cell wall composition and saccharification of cassava pulp

Genome-wide association studies unveils the genetic basis of cell wall composition and saccharification of cassava pulp

Impact of Cassava Cultivars on Stylet Penetration Behavior and Settling of Bemisia tabaci Gennadius (Hemiptera: Aleyrodidae).

This study investigates the settling preferences and feeding behavior of the Bemisia tabaci whitefly on six cassava cultivars using electrical penetration graph techniques. Six distinct electrical penetration graph waveforms-non-probing, stylet pathway, phloem salivation, phloem ingestion, intracellular puncture, and xylem feeding-were identified and analyzed. Significant differences in the frequency and duration of these waveforms were observed among the cassava cultivars. The whiteflies spent the majority of their time in the non-probing phase, particularly on the Huaybong 80, Kasetsart 50, Rayong 9, and Rayong 72 cultivars. CMR-89 cultivar exhibited higher total probe durations in the phloem salivation and ingestion waveforms, suggesting a greater potential for transmission of the Sri Lankan cassava mosaic virus. The study also examined trichome density and size across the cassava cultivars, revealing that CMR-89 had the highest density and small trichomes, while Huaybong 80 had the lowest density. Trichome characteristics significantly impacted whitefly behavior: larger trichomes were negatively correlated with whitefly settling, whereas higher trichome density was positively correlated with longer settling durations. These findings indicate that trichome-based resistance mechanisms are crucial in whitefly deterrence. Overall, the results suggest that cultivars with lower trichome density and larger trichomes are more resistant to whitefly infestation and subsequent Sri Lankan cassava mosaic virus transmission. These insights are valuable for cassava breeding programs focused on enhancing pest resistance, highlighting the importance of trichome characteristics in developing more resilient cassava varieties.

Evaluation of the Sensitivity of Thirteen (13) Promising Cassava Varieties to Diseases (Viruses-Bacteria) and Pests (Mealybugs-Mites) in Central Côte d’Ivoire

Cassava (<i>Manihot esculenta</i>), a plant with starch-rich roots, plays a crucial role in global food security. For producers, it has become both a subsistence and cash crop. In Côte d’Ivoire, it ranks second among crops after yam. However, cassava is severely affected by bacteria, fungi, viruses, mites, and mealybugs, causing yield losses ranging from 20% to 90%. This study was conducted at the Food Crop Research Station (FCRS) of the National Center for Agronomic Research (NCAR) in Bouake in central Côte d’Ivoire. The plant material consisted of thirteen varieties of cassava of the <i>Manihot esculenta</i> species, from the national cassava collection. It aimed to assess the performance of thirteen promising cassava varieties, originating from the national cassava collection, against these diseases and pests under natural infestation conditions. The results revealed that the Yacé variety showed the highest sensitivity to viruses, with an incidence (I) of 96.25% and a severity index (IGS) of 2.8. In contrast, the Yavo variety was the least sensitive, with an incidence of 11.50% and a severity index of 1.3. All varieties studied demonstrated high sensitivity to bacterial blight and mite attacks, with high incidence rates observed in Bocou1 (71.25%) and Bocou3 (68.75%). However, mealybug infestation was relatively low, ranging from 8.75% (Yavo) to 33.75% (Bocou2). Except for mosaic disease, the severity indices for diseases and pests were similar across all varieties.

An optimization method for measuring the stomata in cassava (Manihot esculenta Crantz) under multiple abiotic stresses.

As a gateway for gas exchange, pores regulate the transport of air and water in carbon assimilation, respiration, and transpiration to quickly adapt to environmental changes. Therefore, the study of stomatal movement characteristics of plants is helpful to strengthen the understanding of the mechanism of plant response to multi-environmental stress, and can improve the function of plant resistance to stresses. The stomatal movement of Arabidopsis leaves was observed by staining the stomata with rhodamine 6G, but this method has not been reported in other plant leaf stomata studies. Taking cassava as an example, the correlation between cassava stomatal movement and cassava response to stress was observed by using and improving the staining method. Rhodamine 6G is a biological stain widely used in cell biology and molecular biology. It was found that 1 μM rhodamine 6G could stain the stomata of cassava without affecting stomatal movement (n = 109, p < 0.05). In addition, we proposed that stomata fixed with 4% concentration of formaldehyde after staining were closest to the stomatal morphology of cassava epidermis, so as to observe stomatal movement under different environmental stresses more accurately. Previous methods of measuring stomatal pore size by autofluorescence of cell wall needs to fix the cells for 6 h, but Rhodamine staining can only be observed in 2 min, which greatly improves the experimental efficiency. Compared with the traditional exfoliation method (e.g., Arabidopsis), this method can reduce the damage of the leaves and observe the stomata of the whole leaves more completely, so that the experimental results are more complete. In addition, the method enables continuous leaf processing and observation. Using this method, we further compared four different cassava varieties (i.e., KU50, SC16, SC8, and SC205) and found that there are differences in stomatal density (SD) among cassava varieties, and the difference in the SD directly affects the stress resistance of cassava (n = 107, p < 0.001). This finding has important implications for studying the mechanism of plant response to environmental stress through stomata.

Impact of Nutrient Management Practices in Cassava on the Growth and Yield of Red Gram in an Additive Series Intercropping System in the Southern Laterites of Kerala

Cassava-legume intercropping is widely promoted by virtue of the ecological, nutritional and productive benefits and the choice of the intercrop is crucial in realizing the potentials envisaged. The performance of red gram (Cajanus cajan (L.) Millsp.) as an intercrop in cassava was evaluated in randomized block design at College of Agriculture, Vellayani, Kerala Agricultural University in three replications with different nutrient management practices in the main crop as treatments. Potassium efficient cassava variety Sree Pavithra was tested with varying levels of N, P and K. The treatments included T1 (100 % recommended dose of fertilizers), T2 (100 % RD N and P + 50 % K), T3 (100 % RD N and P + 25 % K), T4 (100 % RD N and P + 0 % K), T5 (50 % RDF), T6 (50 % RDF + PGPR Mix 1), T7 (50 % RD N and P + 25 % K), T8 (50 % RD N and P + 25 % K + PGPR Mix 1), T9 (50 % RD N and P + 0 % K), T10 (50 % RD N and P + 0 % K + PGPR Mix 1) and control (no fertilizer application). Cassava growth and yield was found to be superior in the treatments involving the consortium biofertilizer PGPR Mix 1 and was the highest in 50 % RD N and P + 0 % K + PGPR Mix 1 liquid application. The performance of red gram as an intercrop was found to be influenced by the canopy growth in cassava and yields were 80-89 per cent less than in sole cropping. The land equivalent ratio was more than one in PGPR included treatments alone indicating that intercropping was not advantageous in other treatments.

Determination of drying performance of different slice thicknesses from different cassava varieties using hybrid dryer

Determination of drying performance of different slice thicknesses from different cassava varieties using hybrid dryer

Preferential Adoption of Bio-fortified Pro-vitamin A Yellow cassava varieties as Smart Feeding for Rural Farmers in Southeast Nigeria

Preferential Adoption of Bio-fortified Pro-vitamin A Yellow cassava varieties as Smart Feeding for Rural Farmers in Southeast Nigeria

TREND OF CASSAVA YIELD/PRODCUTION IN IN KOGI EAST SENATORIAL DISTRICT, KOGI STATE, NIGERIA

This study examined the trends in cassava yield and production in the Kogi East Senatorial District of Kogi State, Nigeria, focusing on the perceptions of local farmers regarding yield changes over the past five years and the factors influencing these trends. A total of 403 respondents were surveyed, revealing that 71.3% of the farmers perceived an increase in cassava yields, while 28.7% reported stable yields. The primary factors contributing to the perceived increase included the use of improved cassava varieties (58.1%) and climate variability (41.9%). Furthermore, the statistical analysis indicated a stationary R-squared value of 0.792, suggesting a robust model fit for predicting future production trends. Forecasts indicated a steady increase in cassava production per hectare from 2024 to 2033, with projected yields rising from 17.33 tons per hectare in 2024 to 18.54 tons per hectare by 2033. Despite these positive trends, the study identified significant challenges posed by climate variability, with 76.7% of respondents recognizing a high impact on production. The findings underscore the urgent need for targeted interventions, including the promotion of climate-resilient cassava varieties, improved access to quality planting materials, and the implementation of sustainable agricultural practices. Overall, this study provides critical insights into the cassava production landscape in Kogi East and highlights the importance of collaborative efforts among stakeholders to enhance productivity and ensure food security in the region.

Agronomic potential of four cassava (Manihot esculenta Crantz) varieties grown on soils fertilized with cocoa shell compost and chicken droppings compost in Côte d’Ivoire

This study was conducted in the Lamto area to evaluate the effect of cocoa shell compost and chicken droppings compost on cassava agronomic variables. The main aim is to increase cassava production, which is in relative decline due to soil impoverishment through organic amendments. The evaluation led to the monitoring of plant development until harvest by measuring some agronomic variables of growth and yield of four varieties of cassava, Alleda agba, Bonoua, Six mois and Yacé each grown on soil fertilized with cocoa shell compost or chicken droppings compost. The experimental design used for this study was a complete randomized block design with 3 replicates. The results showed that the two fertilizers used, being rich in mineral elements, improved the agronomic variables of cassava, superior to the control. This was reflected in a high number of stems per cutting (3.62). However, the chicken droppings compost gave the best development in stem length for the Six mois variety (121.10 cm). The Bonoua variety gave the largest diameter stems (21.98 mm). This variety gave the highest number of leaves (59) and a wider span (109 cm) with wider (16.75 cm) and longer (17.96 cm) leaves. As for yields, the best was obtained with the Bonoua variety, respectively 27.13 t/ha and 35.26 t/ha with cocoa shell compost and chicken droppings compost compared with 12.77 t/ha for the control. Thus, compost and chicken droppings compost can be recommended to improve cassava productivity in Côte d'Ivoire.

Assessing realized genetic gains in biofortified cassava breeding for over a decade: Enhanced nutritional value and agronomic performance

AbstractBiofortified cassava (Manihot esculenta) plays a crucial role in enhancing the nutritional value of this essential staple, particularly in regions with limited dietary diversity and prevalent nutritional deficiencies. The cassava program at the International Center of Tropical Agriculture has dedicated over a decade to increase β‐carotene content in biofortified cassava, simultaneously focusing on improving yield, dry matter, and plant architecture. This paper presents realized genetic gains in biofortified cassava by analyzing the data from replicated multilocation breeding yield trials at the target population of environments spanning a 10‐year period (2013–2022). Following data curation, we observed significant positive genetic gains per year for β‐carotene content (7.03%), fresh yield (4.15%), dry matter content (0.55%), and height at the first branch (1.29%). A negative correlation between β‐carotene content and dry matter content was observed within 78% of trials. Moreover, our study uncovered a significant negative correlation between β‐carotene content and fresh root yield (r = −0.22, p &lt; 0.01) and an unfavorable positive correlation between β‐carotene content and the number of branches (r = 0.23, p &lt; 0.01). Such negative correlations between β‐carotene content and farm‐preferred traits presented substantial challenges for the development of biofortified cassava varieties. This research showed significant genetic gains and navigated the complexities of biofortified cassava development, providing breeding insights to enhance nutritional value while optimizing agronomic performance.

Fertilizer management practices for cassava in acid dryland of Sukabumi Regency, West Java

The productivity of cassava in acid dryland is generally still low. Fertilization, land amelioration, and superior varieties are the main solutions for increasing cassava productivity. This research aimed to determine the response of high-yielding varieties and fertilization technology packages to the growth and yield of cassava in acid dryland of Sukaharja Village, Warung Kiara District, Sukabumi Regency, West Java. The contents of organic carbon, nitrogen, and magnesium of the soil is below the minimum threshold, so the application of N fertilizer, organic matter, and ameliorant is expected to increase plant growth. The research consisted of two treatment factors: two cassava varieties and three fertilization technologies. The treatments were arranged in a completely randomized split-plot experimental design with three replications with variety as the main plot and fertilization technology package as the subplots. The treatment effect was observed on the character of plant height, wet biomass weight, stem diameter, number of tubers, tuber length, tuber diameter, tuber weight (large and small) per plant, and tuber yield per plot to be converted per ha. Tuber quality was observed by observing water content, percent dry matter, and starch yield. The results showed that the fertilization technology package increased plant height, fresh biomass weight, stem diameter, large tuber weight per plant, and yield per hectare in both varieties. Differences in varieties and fertilization technology packages have no effect on starch levels.

Modified Alexnet Architecture for Classification of Cassava Based on Leaf Images

The objective of this study is to address the drawbacks of conventional classification approaches through the implementation of deep learning, specifically a modified AlexNet. The primary aim of this study is to precisely categorize the four distinct varieties of cassava, namely Manggu, Gajah, Beracun, and Kapok. The cassava dataset was obtained from farmers in Lamongan, Indonesia, and was used as a source of information. Data collection on cassava leaves was carried out with agricultural research specialists. A total of 1,400 images are included in the dataset, with 350 images corresponding to each variety of cassava produced. The central focus of this research lies in a comprehensive evaluation of the modified AlexNet architecture's performance compared to the original AlexNet architecture for cassava classification. Multiple scenarios were examined, involving diverse combinations of learning rates and epochs, to thoroughly assess the robustness and adaptability of the proposed approach. Among the evaluation criteria that were rigorously examined were accuracy, recall, F1 score, and precision. These metrics were used to determine the predictive capabilities of the model as well as its potential utilization in the actual world. The results show that the modified AlexNet design has better performance than the original AlexNet for recall, accuracy, precision, and F-1 score, all achieving a rate of 87%. In situations where a learning rate of 0.0001 and an epoch count of 150 are utilized, the performance of the approach stands out significantly, displaying an excellent level of competency. Nevertheless, it is crucial to recognize that distinct fluctuations in performance were noted within particular contexts and with diverse learning rates.

Physico-chemical and nutritional characteristics of 12 varieties of cassava (Manihot esculenta Crantz, 1766) grown in the Republic of Guinea

Cassava is a distinctive contributor to food security and a source of income for smallholder farmers. Despite the importance of this agricultural product, very little data is available in Guinea, especially concerning the varieties grown and their nutritional composition. The aim of this research was to study the physico-chemical and nutritional characteristics of 12 varieties of cassava grown in Guinea with a view to selecting varieties that could be used to produce a &lt;&lt;Gari&gt;&gt; of better quality. Cassava tubers were collected in 6 regions in Guinea. The physico-chemical analyses were carried out on the pH and moisture content of the cassava paste from each of the 12 varieties, while the nutritional quality was determined on the basis of the composition of the varieties in carbohydrates, proteins, lipids and minerals. In general, pH values ranged from 6.29 to 7.29 while moisture levels ranged from 51.64% to 58.94%. In addition, all the varieties analysed were those rich in carbohydrates (with levels between 42.36% and 51.17%) but low in fat (values between 0.30% and 3.56%). On the other hand, three varieties, namely Farawoulen, Konko and Samouya, are the richest in protein with values of 8.05%, 5.48% and 4.23% respectively. In short, these cassava varieties produced in Guinea could be used, taking into account their biochemical composition, in future gari production work.

Evaluating the Impact of Moisture Content and Loading Orientation on the Geometrical Characteristics and Mechanical Behavior of Cassava Tubers

This study investigates the geometrical and mechanical properties of two cassava varieties: ‘Newly Elected No. 48’ and ‘Jin Yue HRMUS’. We analyzed various properties, including width, length, geometric diameter, thickness, compression firmness, shape ratio, surface area, shear strength, rupture force, and shear rupture force (SRF), at different moisture content (MC) levels ranging from 35.0 to 80.0% wet basis. Our findings indicate that all mechanical properties of cassava (MPC) were significantly influenced by moisture content within this range. Specifically, as moisture content decreases, the compression rupture force (CRF) increases linearly in the vertical direction, while a quadratic relationship is observed in the horizontal direction, characterized by an initial increase followed by a decrease. Additionally, a quadratic relationship was established between moisture content and firmness. In contrast, shear fracture force and strength exhibited a quadratic relationship that decreased initially and then increased with rising moisture content. Furthermore, both compression and shear fracture forces were significantly higher in the vertical loading direction compared to the horizontal direction. Notably, the ‘Jin Yue HRMUS’ variety demonstrated greater mechanical strength than the ‘Newly Elected No. 48’. These findings provide valuable insights for developing, optimizing, and evaluating cassava harvesting and processing machinery.

Assessment of the Availability and Accessibility to Improved Cassava Varieties by Smallholder Farmers in Siaya County, Kenya

Assessment of the Availability and Accessibility to Improved Cassava Varieties by Smallholder Farmers in Siaya County, Kenya

Cassava breeding: Classical to recent breeding approaches for food, industry and climate resilience

Cassava ranks as the fourth-most significant starchy root crop in underdeveloped countries in terms of future food and acting as a key source of income for small and marginal farmers. To meet the growing demands for food security and economic development, it is imperative to develop improved cassava varieties that offer higher yields, enhanced nutritional content, safer for consumption, greater resistance to diseases and climate change. The development of these improved varieties necessitates advancements in breeding techniques, leveraging both traditional methods and modern biotechnological tools. However, a major challenge in cassava breeding is heterozygous nature and the crop’s sparse flowering, which limits the potential for sexual reproduction, thereby constraining breeding efforts for predominantly clonal selection. The continuous clonal propagation impedes genetic diversity and the introduction of novel traits, narrowing the overall progress of breeding programs. Integrating genomic tools and accelerating the adoption of biotechnological advancements can overcome these limitations and expedite the development of superior cassava varieties. This review highlights the need of cassava breeding for addressing these challenges with conventional as well as with new breeding techniques with the aim to provide a comprehensive understanding of the current scenario and future directions of cassava breeding research. Key words: Climate change, CRISPR/Cas 9, New breeding techniques, PPD, speed breeding, Waxy cassava

Occurrence and Distribution of Major Cassava Pests and Diseases in Cultivated Cassava Varieties in Western Kenya.

Cassava is an important food crop in western Kenya, yet its production is challenged by pests and diseases that require routine monitoring to guide development and deployment of control strategies. Field surveys were conducted in 2022 and 2023 to determine the prevalence, incidence and severity of cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), whitefly numbers and incidence of cassava green mite (CGM) in six counties of western Kenya. Details of the encountered cassava varieties were carefully recorded to determine the adoption of improved varieties. A total of 29 varieties were recorded, out of which 13 were improved, although the improved varieties were predominant in 60% of fields and the most widely grown variety was MM96/4271. The CMD incidence was higher in 2022 (26.4%) compared to 2023 (10.1%), although the proportion of CMD attributable to whitefly infection was greater (50.6%) in 2023 than in 2022 (18.0%). The CBSD incidence in 2022 was 6.4%, while in 2023 it was 4.1%. The CMD incidence was significantly lower (5.9%) for the improved varieties than it was for the local varieties (35.9%), although the CBSD incidence did not differ significantly between the improved (2.3%) and local varieties (9.7%). Cassava brown streak virus (CBSV) and Ugandan cassava brown streak virus (UCBSV) were both detected. Most infections were single CBSV infections (82.9%), followed by single UCBSV (34.3%) and coinfection with both viruses (16.7%). Whiteflies were more abundant in 2023, in which 28% of the fields had super-abundant populations of >100/plant, compared to 5% in 2022. KASP SNP genotyping designated 92.8% of the specimens as SSA-ECA for 2022, while it was 94.4% for 2023. The cassava green mite incidence was 65.4% in 2022 compared to 79.9% in 2023. This study demonstrates that cassava viruses, whiteflies and cassava green mites continue to be important constraints to cassava production in western Kenya, although the widespread cultivation of improved varieties is reducing the impact of cassava viruses. The more widespread application of high-quality seed delivery mechanisms could further enhance the management of these pests/diseases, coupled with wider application of IPM measures for whiteflies and mites.