Improved Cassava Production Research Articles

Elevated viral small RNA profiling in cassava cultivars suppress the occurrence of Cassava brown streak disease (CBSD)

Cassava brown streak disease (CBSD), caused by cassava brown streak virus (CBSV) and; Ugandan cassava brown streak virus (UCBSV) causes the most destructive cassava disease in Tanzania. Thus, breeders urgently need CBSD-resistant cultivars to combat the impact of this disease, safeguard cassava production, improve the yields and secure food supply for communities reliant on this staple crop. In this study, we used four cassava cultivars; Albert, KBH 2002/135, KBH 2006/026 and Kiroba to explore how viral small interfering RNA (vsiRNAs), an antiviral silencing mechanism, confers CBSD resistance. Cassava plants were inoculated by grafting method using the single infection of CBSV, UCBSV and mixed infection of these viruses (co-infection). Total RNA was extracted from leaves of each cultivar followed by deep sequencing. The result showed that high level of vsiRNAs was produced in inoculated plants, with the most prominent class being 21 and 22 nucleotides. Kiroba produced the highest level of vsiRNA in both CBSV and UCBSV, whereas KBH 2006/026 produced high level of vsiRNA only with UCBSV infections. In contrast to UCBSV, inoculation with CBSV stimulated severe symptoms but relatively low levels of vsiRNA. Co-infection treatment showed a more complex interaction between the host and virus, with variations in the severity and amount of vsiRNA produced. We conclude that resistance to CBSD varies depending on the type of cultivar and virus species, and the occurrence of CBSD is suppressed in plants with elevated vsiRNA. Therefore, a good understanding on the resistance status of parental materials for breeding is recommended to breeders as a basis for improving cassava production.

Proyeksi Produksi dan Keunggulan Komparatif Perdagangan Ubi Kayu Indonesia

Indonesia is one of the largest cassava importers among the ten cassava-producing countries. While there is a production surplus, Indonesia's cassava imports tend to increase yearly to meet industrial needs. This research has four objectives. First, to analyze (change) the production and trade of the world's largest cassava-producing countries in the future and the implications for Indonesia. Second, to evaluate the enabling environment for cassava production and marketing. Third, to identify the comparative advantages of Indonesia's cassava trade compared to other producing countries. Fourth, evaluate the potential for partnerships to increase Indonesian cassava production and marketing sustainability. This study used FAOSTAT data (1961-2020) projected to 15 years (2021-2035) with a double exponential smoothing method. Comparative advantages are evaluated with the Relative Export Advantage, Relative Import Advantage, Relative Trade Advantage, Net Export, and Grubel-Lloyd indexes. This study found that Indonesia's cassava harvested area will likely decrease while cassava imports will likely increase. Indonesia has a comparative advantage in exporting cassava. However, it is under-optimized due to inefficient cassava trades at the regional level and less successful cassava partnerships (between farmers and industry). This study recommends improving cassava production and trade conditions through improving enabling environments and collaborations between actors in the cassava chain.

PGPR Preparation Training to Improve Cassava Production for KOPASAMU Farmers in Kalasan

Cassava farmers grouped in Koperasi Sejahtera Muhammadiyah (KOPASAMU) in Kalasan often faced challenges of low production level of cassava (5 - 10 tonnes/ha) due to lack of growth and unhealthy conditions as a result of plant pest disturbance. Previous studies have demonstrated that such problem may be alleviated by the application of Plant Growth Promoting Rhizobacteria (PGPR). PGPR is a consortium of bacteria-producing plant growth hormones that improve cassava plant health and increases production. In addition to the use of PGPR, plant productivity may also be improved by using organic fertiliser, inoculated with mycorrhiza, stem wounding, and foliar fertiliser spray. The purpose of this community service was to improve farmers’ understanding and skills in applying PGPR to increase cassava production. The activities of the services were: (1) extension training on PGPR, (2) training on PGPR preparation, and (3) mentoring in the application of PGPR in cassava production demonstration plots (demplot). The results of the community services demonstrated that the extension programme has increased farmers’ understanding of PGPR by 100%, also resulting in an increase in farmers’ spirit and passion for applying PGPR. Following the extension programme, it was observed that the farmers’ skills have improved by 100%. However, among the farmers who were involved in the extension programme, 54.55% stated that they already mastered the PGPR preparation, while the other 45.45% stated that they required further training to improve their skills.

Improved cassava (Manihot esculenta Crantz) growth and production by application of potassium

Indonesia is the fifth countries in term of cassava production in the world. The biggest cassava area in Indonesia is Lampung. One of the important nutrient fertilizers to improve cassava production is potassium. Consequently, the objective of this study was to evaluate distribution of photoassimilate by determining cassava growth and production under different potassium dosages. Treatment was arranged by factorial (2x3) in randomized complete block design (RCBD) with two reps. The first factor was two cassava clones, UJ3 and UJ5 and the second factor was three potassium (KCl) dosages, 0, 150, and 300 kg/ha. The variables observed in this study were plant height, stem diameter, fresh weight and dry weight of leaf, total root number and swollen root number, distribution of root number, root length, root distribution, and root weight. The result showed that under fertilizer of 300 kg KCl/ha, stem dry weight of UJ3 and UJ5 was not significantly different however root fresh weight of UJ3 seemed higher compared to that of UJ5. It seems that UJ3 cassava clone is more responsive to potassium fertilizer than UJ5 cassava clone.

Analysis of the molecular and biochemical mechanisms involved in the symbiotic relationship between Arbuscular mycorrhiza fungi and Manihot esculenta Crantz.

Plants and arbuscular mycorrhizal fungi (AMF) mutualistic interactions are essential for sustainable agriculture production. Although it is shown that AMF inoculation improves cassava physiological performances and yield traits, the molecular mechanisms involved in AM symbiosis remain largely unknown. Herein, we integrated metabolomics and transcriptomics analyses of symbiotic (Ri) and asymbiotic (CK) cassava roots and explored AM-induced biochemical and transcriptional changes. Three weeks (3w) after AMF inoculations, proliferating fungal hyphae were observable, and plant height and root length were significantly increased. In total, we identified 1,016 metabolites, of which 25 were differentially accumulated (DAMs) at 3w. The most highly induced metabolites were 5-aminolevulinic acid, L-glutamic acid, and lysoPC 18:2. Transcriptome analysis identified 693 and 6,481 differentially expressed genes (DEGs) in the comparison between CK (3w) against Ri at 3w and 6w, respectively. Functional enrichment analyses of DAMs and DEGs unveiled transport, amino acids and sugar metabolisms, biosynthesis of secondary metabolites, plant hormone signal transduction, phenylpropanoid biosynthesis, and plant-pathogen interactions as the most differentially regulated pathways. Potential candidate genes, including nitrogen and phosphate transporters, transcription factors, phytohormone, sugar metabolism-related, and SYM (symbiosis) signaling pathway-related, were identified for future functional studies. Our results provide molecular insights into AM symbiosis and valuable resources for improving cassava production.

Comparative analyis of cost and return of improved cassava production in Awka South LGA, Anambra State, Nigeria

IITA developed several new varieties during 1976-1985 for the benefit of cassava farmers. The study had four specific objectives which described the socio-economic characteristics of the cassava farmers, identify the perception of cassava farmers on the IITA improved varieties, ascertain the cost and profitability of cassava production and the constraints faced by the farmers. A multi stage and purposive sampling method was used in the selection of 100 respondents, 50 adopters and 50 non-adopters of IITA intervention in the study area. A structured questionnaire was used to collect data from the respondents and these data were analyzed using gross margin, likert and descriptive analysis (frequency, percentage and mean). The result showed that majority of cassava farmers in the study area were male and majority of them were married. The mean farm size was 1.8ha which implied that production was in a small scale in the study area. The result also revealed the net return for adopters was N230,800 and N146,000 for non-adopters, which denoted that cassava production was more profitable to the adopters of the improved cassava varieties. The result further revealed that the inadequate information on availability of planting materials was the main constraints faced by the cassava farmers. This study concluded that the International Institute of Tropical Agriculture (IITA) improved cassava varieties increased the profitability of cassava production. Therefore, it is recommended that extension agents should train and encourag farmers to use IITA varieties to increase their profitability in the study area.

Improving soil physical properties and cassava productivity through organic manures management in the southern Cameroon

Cassava cultivation causes serious soil fertility depletion in Cameroon. Organic manures can contribute to maintaining the productivity and sustainability of cassava production systems due to their availability and cheapness. This study was conducted during two successive cropping seasons (2016/2017 and 2017/2018) in the Southern Cameroon, to determine the effects of organic manures on soil physical properties, and cassava growth and yield. Tithonia diversifolia fresh biomass (TB) and poultry manure (PM) were used as organic manures. Different treatments were used, namely: (i) control (no amendment), (ii) mineral fertilizer (MF (450 kg ha−1 13-13-23 NPK + 100 kg ha−1 Urea)), (iii) two rates of TB (applied at 10 and 20 t ha−1), (iv) two rates of PM (applied at 10 and 20 t ha−1) and (v) two rates of the mixture of TB and PM (applied at 5 and 10 t ha−1 each). The experimental designed was randomized complete block with three replicates per treatment. The application of TB, PM and TB + PM (mixture) lowered bulk density by 14–22.6%, 21.5–26.2% and 18.2–25%, respectively. While total porosity and water holding capacity were increased with manure application by 9.8–15.1% and 13.3–30.3%, respectively. The mineral fertilizer had no significant effect on these soil physical parameters. Application of TB and PM either solely or mixed significantly improved growth of cassava. Stem height, stem diameter and canopy diameter increased by 34.3–60%, 17.4–30.4% and 19.7–32.7%, respectively. Organic manures performed better than the mineral fertilizer. Aboveground dry biomass and fresh tubers yield increased by 21.7–59.6 and 76.6–112.2% with organic manures, and by 23.2 and 68.5% with mineral fertilizer, respectively. The best performance of cassava in terms of fresh tubers yield (51.78 t ha−1) occurred with the mixture of TB and PM applied at 10 t ha−1 each. The study revealed that fresh biomass of Tithonia diversifolia and poultry manure can be used to improve cassava production and sustain soil productivity in the humid forest zone of Southern Cameroon.

Cassava Production Efficiency in Southern Ethiopia: The Parametric Model Analysis

Due to capital constraints and land scarcity in developing countries, introducing new technology to boost productivity is difficult. As a result, working to improve cassava production efficiency is the best option available. Cassava is increasingly being used as a food source as well as an industrial raw material in the production of economic goods. This study estimates cassava production efficiency and investigates the causes of inefficiency in southern Ethiopia. Cross-sectional data from 158 households were collected using a systematic questionnaire. The Cobb-Douglas (CDs) stochastic frontier production model was used to calculate production efficiency levels. The computed mean result showed technical efficiency (TE), allocative efficiency (AE), and economic efficiency (EE) levels of 74, 90, and 66%, respectively. This demonstrated that existing farm resources could increase average production efficiency by 26, 10, and 34%, respectively. The study found that land size, urea fertilizer application, and cassava planting cut all had a positive and significant effect on cassava production. It was discovered that TE was more important than AE as a source of benefit for EE. Inefficiency effects modeled using the two-limit Tobit model revealed that household head age, level of education, cassava variety, extension contact, rural credit, off-farm activities involvement to generate income, and farm size were the most important factors for improving TE, AE, and EE efficiencies. As a result, policymakers in government should consider these factors when addressing inefficiencies in cassava production. It is especially important to provide appropriate agricultural knowledge through short-term training, to provide farmers with access to formal education, to access improved cassava varieties, and to support agricultural extension services.

Technological Innovations for Improving Cassava Production in Sub-Saharan Africa.

Cassava is crucial for food security of millions of people in sub-Saharan Africa. The crop has great potential to contribute to African development and is increasing its income-earning potential for small-scale farmers and related value chains on the continent. Therefore, it is critical to increase cassava production, as well as its quality attributes. Technological innovations offer great potential to drive this envisioned change. This paper highlights genomic tools and resources available in cassava. The paper also provides a glimpse of how these resources have been used to screen and understand the pattern of cassava genetic diversity on the continent. Here, we reviewed the approaches currently used for phenotyping cassava traits, highlighting the methodologies used to link genotypic and phenotypic information, dissect the genetics architecture of key cassava traits, and identify quantitative trait loci/markers significantly associated with those traits. Additionally, we examined how knowledge acquired is utilized to contribute to crop improvement. We explored major approaches applied in the field of molecular breeding for cassava, their promises, and limitations. We also examined the role of national agricultural research systems as key partners for sustainable cassava production.

Adoption of Improved Cassava Production Technologies Among Small-Scale Farmers in Anambra State, Nigeria

The study on the adoption of improved cassava production technologies among small-scale cassava famers in Anambra State, Nigeria, specifically; described the socioeconomic characteristics of small-scale cassava farmers, determine the adoption levels of improved cassava production technologies, examine the effects of socioeconomic variables on the adoption level and identified constraints to adoption of improved cassava production technologies in the area. A multi stage sampling technique was employed to randomly sample a cross section of 120 small-scale cassava farmers. Data were collected using a well-structured questionnaire. The data were analyze with a combination of tool like descriptive statistics, multiple regression and principal factor analysis. The study revealed that the average age of the cassava farmers was 44.08 out of which 51.67% are male. The average educational level (9.17), farming experience (14.89), household size (5.86), annual income (861.103 USD), farm size (0.15 ha) and extension contacts (3.59) were also revealed. The results further showed that out of the eleven (11) improved cassava production variables considered, the respondents have not fully adopted any of the technologies. Findings on influence of socioeconomic characteristics on adoption shows that F-statistic value of 4.05*** was significant at 1% level of significance, which implies that the predictor variables influenced adoption. Major constraints of the cassava farmers were rotated into three component factors which are institutional (25.4%), economic (17.7%) and managerial factors (12.6%) using principal factor analysis. A KMO of 0.580 and cumulative Eigen-value of 55.7% explained the variance of factors. We therefore encourage extension agents to sit up in disseminating recent innovation to farmers.

Measurement of Technical Efficiency of Women Cassava Farmers in Ankpa Local Government Area, Kogi State, Nigeria

The study was about technical efficiency of women cassava farmers in Ankpa Local Government Area of Kogi State, Nigeria. A simple random sample of 120 women cassava farmers were interviewed with a structured questionnaire and information concerning their socioeconomic attributes, revenue realized and cost incurred in cassava production were obtained. The data were analysed with the use of stochastic frontier Cobb-Douglas production function and the inefficiency model. Results indicated that farm size, family labour, hired labour, equipment depreciation, cassava stems, fertilizers and transportation had positive coefficients and thus influenced cassava output positively. Education, household size, farming experience and extension visits increased farmers’ technical efficiency. Many farmers had high technical efficiency. The mean technical efficiency was 76 percent with a maximum of 98 percent technical efficiency. Recommendation made to improve cassava production were making farm inputs available at affordable prices, review of land tenure system, opening up of more credit agencies and increase extension visits among others.

Effects of root and tuber expansion programme on the performance of cassava farmer-beneficiaries in Edo State, Nigeria

The study assessed effects of Root and Tuber Expansion Programme (RTEP) on the performance of cassava farmer-beneficiaries in Edo State, Nigeria. The population of the study comprised all cassava farmers in Edo State that participated in RTEP. A multi-stage sampling procedure was used to select 120 respondents for the study. Data were collected from primary source through the use of validated interview schedule. Analytical tools used were descriptive statistics and multiple linear regression. Findings show that the RTEP made best achievements in conduct of training/workshop on improved cassava production practices, followed by increase in cassava farmers’ yield and income. The cassava farmer-beneficiaries were fully involved in the programme’s activities such as multiplication of improved cassava varieties and distribution ( = 2.86), extension meetings and field visits ( = 2.81) and lectures organized by extension workers ( =2.77). Socio-economic variables such as age, sex, educational level, farming experience, membership of social organization, extension contact and annual income statistically and significantly influenced level of involvement in the RTEP activities at 5% level. Inadequate fund for start-off, delays in credit/agro-input disbursement, approval of work plans, budgets and procurements, inadequate programme group coverage and gender issue not addressed were major constraints to involvement of the farmers in RTEP. The need for timely and adequate supply of agro-inputs and credits at subsidized rate by the service providers was recommended. This would boost the capabilities of the farmers to start field operations timely, realize more profit, and achieve higher levels of involvement in the RTEP activities.

Strategic Policies in Expanding Frontiers of Food Security among Cassava-based Farmers in Cross River State, Nigeria

The research was carried out to identify the possible constraints and development of strategic policies in expanding and improving cassava production and processing amongst cassava value chain actors in Cross River State, Nigeria. Data generated from the research the 150 cassava producers and processors (cassava value chain actors) through the use of well- define structured interview schedule was collated. The Multistage sampling procedure was adopted in selection of farmer respondents. The multivariate analytical technique was used in analyzing generated data employing the statistical application software of Genstat version 12. The eigen value, percentage variations and loading values contributing to low cassava output were used in achieving the objectives. The results showed that the major constraints to cassava production and processing were agronomic, technical/institutional and financial constraints. The major policy strategies should include a global, national, regional and community strategies all geared towards the evolution of industry analysis for improving cassava productivity in the study area through the development of the traditional farming systems, making good planting material accessible to farmers and on time and at lowest possible prices; the provision of credit facilities to the resource poor cassava –based farmers in the area with no collateral; the establishment of cassava product based cottage industries in the area for cassava value chain development; provision of adequate cassava processing equipment and the formation of cassava farmers’ multipurpose cooperative societies to enhance farmers’ access to benefit from world bank assisted programmes; have free access to basic information and production facilities. The study, therefore, recommended that cassava product based cottage industries be established in the study area in order to encourage both producers and processors in the value addition chain. This will also provide employment and likewise encourage the restive youths in the region to venture into agriculture as a business for economic returns, growth and development of the area. The identified constraints with the higher loading values for each of the principal multivariate should be strengthened using appropriate development strategies/policies to ensure food security and increased farm income for cassava – based farmers in the region.

Phenotypic variation of cassava root traits and their responses to drought.

Premise of the StudyThe key to increased cassava production is balancing the trade‐off between marketable roots and traits that drive nutrient and water uptake. However, only a small number of protocols have been developed for cassava roots. Here, we introduce a set of new variables and methods to phenotype cassava roots and enhance breeding pipelines.MethodsDifferent cassava genotypes were planted in pot and field conditions under well‐watered and drought treatments. We developed cassava shovelomics and used digital imaging of root traits (DIRT) to evaluate geometrical root traits in addition to common traits (e.g., length, number).ResultsCassava shovelomics and DIRT were successfully implemented to extract root phenotypes, and a large phenotypic variation for root traits was observed. Significant correlations were found among root traits measured manually and by DIRT. Drought significantly decreased shoot dry weight, total root number, and root length by 84%, 30%, and 25%, respectively. High adventitious root number was associated with increased shoot dry weight (r = 0.44) under drought.DiscussionOur methods allow for high‐throughput cassava root phenotyping, which makes a breeding program targeting root traits feasible. We suggest that root number is a breeding target for improved cassava production under drought.

Food Energy Availability from Agriculture at the Farm-Level in Southeastern Nigeria: Level, Composition and Determinants

Among the four pillars of ‘food security’ (i.e., ‘food availability’, ‘food accessibility’, ‘food stability’ and ‘food utilization’), ‘food availability (FA)’ underpins the core concept because at the micro-level it is strongly related to the overall availability of food, which is determined by domestic food production, food imports and food aid. This paper examines the level of food energy availability (FEA) at the farm level, relationships between farm size and FEA and the determinants of FEA based on a survey of 400 households from Ebonyi and Anambra States of Southeastern Nigeria. FEA in this study refers to Partial Food Energy Availability (PFEA) because it excludes procurement of food from other sources, e.g., purchase from the market, borrow/exchange from others and/or receiving as food aid. Results show that the sample is dominated by small–scale farmers (81% of the total sample) owning land <1.00 ha. The average farm size is small (1.27 ha). Farmers grow multiple food crops. Sixty-eight percent of the farmers produced at least two food crops. Average PFEA is estimated at 4492.78 kcals/capita/day produced from one ha of land area. Approximately 30.92% of the total food produced is set aside for home consumption. Among the food crops, 40.70% of cassava output is set aside for home consumption while most of yam and rice are mainly destined for the market. Inverse farm size–PFEA relationship exists amongst the sampled farmers. The regression results reveal that subsistence pressure, profit motive and share of yam in total output significantly reduces PFEA whereas an increase in the share of cassava in total output significantly increases PFEA. A one percent increase in the share of cassava output will increase PFEA by 0.14%. A one percent increase in subsistence pressure will reduce PFEA by 0.98%. Farmers identified a lack of agricultural extension agents, farm inputs and basic infrastructures as the main constraints adversely affecting food production at the farm-level. Policy implications include investments targeted to improve cassava production and measure to reduce future family size by improved family planning to increase PFEA at the farm-level.

Effects of fertilizer and cassava-legume cropping systems on root yields in two agro-ecological zones of Ghana

Cassava is an important food crop in small-holder farming systems in Ghana. Due to the limited use of organic and inorganic inputs, soil fertility becomes a major problem in cassava production systems. A study was conducted at the Soil Research Institute, Kwadaso, in the Forest Agro-ecological zone and the Wenchi Agricultural Station in the Forest-Savannah Transitional zone. The fertilizer rates were 0:0:0, 15:15:15 and 30:30:30 N-P2O5-K2O kg/ha. Cowpea, soybean, and groundnuts were the legumes and cassava was either sole cropped or intercropped with a legume. The objective was to determine the effect of fertilizer and cassava-legume cropping systems on root and grain yields in the two agro-ecological zones. Data on soil characteristics, biomass, grain, and root yields were collected. Growth and yield data were subjected to ANOVA and mean separated using LSD (P < 0.05). Fertilizer application did not influence cassava root yields at Kwadaso but different cropping systems significantly influenced root yield. Cassava-groundnut intercrop gave the highest root yield of 70.2 t/ha. At Wenchi, both cropping system and fertilizer did not affect root yield. This study shows that intercropping cassava with groundnut or cowpea is a good option in improving cassava production. Key words: Agro-ecological zone, cassava-legume intercrop, fertilizer, root yield.

Combating viral mosaic disease of cassava in the Lake Zone of Tanzania by intercropping with legumes

Cassava (Manihot esculenta Crantz) production is constrained by many factors, including the viral cassava mosaic disease (CMD). This study was conducted to explore the potential of intercropping cassava with legumes to reduce CMD effects on cassava production. Local (Lyongo Kwimba) and improved (Suma) cassava varieties were intercropped with three types of grain legumes (groundnut, Arachis hypogea L. var. Upendo; cowpea, Vigna unguiculata (L.) Walp. var. Vuli; and green gram, Vigna radiata (L.) R. Wilczek var. Imara). Monocrops of cassava with and without NPK fertilizer were included as controls. The experiment was established using a randomized complete block design with four replications in a split-plot arrangement for three seasons. Cassava varieties intercropped with cowpeas, green gram, and groundnuts and cassava monocrops with and without NPK fertilizer constituted the main plot and sub-plots, respectively. Whitefly population counts and CMD severity and incidence were measured at regular intervals. Cropping system had a significant effect (P < 0.05) on whitefly populations and CMD severity. Small whitefly populations (0–7.5 individuals per leaf) and low CMD severity (1–2.4 on a 5-point scale) were recorded in improved and local cassava varieties intercropped with green gram. The local cassava variety intercropped with green gram showed low CMD incidences (0%–40%) in all seasons. Generally, growing cassava with green gram proved effective in reducing whitefly populations and CMD incidence and severity. Intercropping cassava with grain legumes may improve cassava production and food security in CMD-prone areas of the Lake Zone of Tanzania and areas with similar environments.

Agro-Morphological Characterization of Cassava (&amp;lt;i&amp;gt;Manihot esculenta&amp;lt;/i&amp;gt; Crantz) Cultivars from Chad

Cassava is a considerable source of food and income for the rural community of the south of Chad. Despite the importance of the diversity of cultivars in situ, their morphological traits and agronomic performance are under investigated. The aim of this study is to characterize and analyze the variability structure of the cassava’s germplasm. Fifty nine cultivars collected from five main cassava growing regions, were evaluated by forty five agro-morphological descriptors in a Fisher design replicated three times. Data were collected at three, six, nine and twelve months after planting. High phenotypic variability was shown within the collection for the color of apical leaf, vein leaf, petiole, roots and pulp. The same case was observed for the root peduncle, the shape of the central leaflet and the root, the cortex root thickness and the texture of root epidermis. Significant to highly significant differences were observed for all the quantitative traits. High variability were shown for the size of the leaf lobe, petiole length, plant height, root number and length, harvest index, above-ground biomass and fresh root weight. Positive correlations were found between the leaflet and leaf lobe number. Fresh root weight was also positively correlated to the root number, length and diameter. Principal component analysis (PCA) on quantitative variable revealed four groups with two of them containing performant cultivars: Group II with small root, high potential yield but less leaflet and leaf lobe and group III characterized by some cultivars with high productivity, more leaflet and leaf lobe, more and bigger roots. At regional level, significant differences were shown within cultivars which were discriminated in relation to their origin region by the number of the leaf lobes. The better cultivars and the interesting traits could be used to improve cassava production in Chad.

English

The study investigated the level of involvement of male and female farmers in small scale production and processing of cassava in Abia State, Nigeria. The objectives of the study were to determine the socioeconomic profile of the cassava farmers, identify the constraints in cassava production and suggest the possible remedies to improve cassava production in the study area. The result revealed that despite the fact that both male and female farmers were actively involved in cassava production and processing, but in terms of labour, the women dominated in most of the activities like planting, weeding and harvesting of cassava. There is also a significant difference in the labour involvement both in production and processing. It also revealed that land ownership was one of the major problems in the area. Women do not own land according to the tradition, and this discourages agricultural production among women. Other constraint like lack of input, lack of fund and high cost of labour were militating against cassava output in Abia State, Nigeria. Based on the constraints, the farmers suggested ways to improve cassava production in the study area. The major suggestions were provision of input, provision of agricultural subsidy/labour. It was recommended that state government should address the problem of farmers by assisting them with improved inputs. Loans should be given to farmers. Land ownership in the rural areas should be addressed by government so that everybody will have equal right to land ownership. Key words: Gender differences, challenges, cassava production, cassava processing and food security.

Sustaining Improved Cassava Production on West African Ferralsols Through Appropriate Varieties and Optimal Potassium Fertilization Schemes

Improved nutrient use efficiency and use of appropriate crop varieties are required towards producing enough food in a sustainable manner. This study assessed the response of three cassava (Manihot esculenta Crantz) varieties to three potassium (K) fertilization rates on West African ferralsols. It aimed at identifying optimal K fertilizer application rates and corresponding appropriate crop varieties for improved and sustainable cassava production. Three K fertilizer rates including 0, 50 and 100 kg K ha-1 were used together with fertilizers nitrogen (N) and phosphorus (P) each at a fixed rate of 60 kg ha-1. The cassava varieties were Gbazekoute (V1), KH (V2) and Moya (V3). Field data including cassava fresh tuber and stover yields, and harvest index (HI) were collected from the 2-yr experiment in which treatments were arranged in a split-plot design, with varieties as main plots and K fertilizer rate as subplots. Mean fresh tuber yield under Gbazekoute (65.5 Mg ha-1) increased by 68.4 and 44.3% as compared with KH (38.9 Mg ha-1) and Moya (45.4 Mg ha-1), respectively, while yield under Moya was superior to that of KH by 16.7%, indicating that tuber yield potential was highest, intermediate and lowest for V1, V3 and V2, respectively. Mean stover yield under Gbazekoute (52.2 Mg ha-1) decreased by 12.6 and 18.7% as compared with KH (59.7 Mg ha-1) and Moya (64.2 Mg ha-1), respectively. Mean harvest index values increased under Gbazekoute (55.7%) by 41 and 34.5 % as compared with KH (39.5%) and Moya (41.4%), respectively, and value under KH was 4.6% lower than that for Moya. The three varieties were responsive to applied fertilizer K rate with the response being highest, intermediate and lowest for the KH, Moya and Gbazekoute, respectively. For the three varieties, the optimum K fertilizer application rate was 50 kg K ha-1. Gbazekoute proved superior over KH and Moya in efficiently allocating assimilates to storage roots at the expenses of the stover. The use of 50 kg K ha-1 together with 60 kg N ha-1 and 60 kg P ha-1 (N60P60K50 kg ha-1) under the Gbazekoute may be a recommended practice towards sustaining improved cassava production on the inherently degraded West African ferralsols.