Academic literature on the topic 'Cassava varieties. eng'

A 56 –day study was conducted to determine the growth performance and nutrient utilization of broiler chickens fed with two varieties (white and yellow) of cassava grit based diets. A total of 240 one day- old unsexed Arbor acre broiler chicks were assigned to eighty dietary treatments in a 2 x 4 factorial arrangement using completely randomized design. Diets were formulated to include two varieties of cassava, TME 419 (white) and TMS 01 1368 (yellow) at four inclusion levels (0, 25, 50 and 75%). Each treatment consisted of 30 birds and three replicates of 10 birds each. Data was collected on growth performance and nutrient digestibility at the end of the starter (4th week) and finisher (8th week) phases. At the starter phase, birds fed 50% white cassava grits diet had the highest (P < 0.05) final weight and weight gain (730.00 and 693.67g/bird). At the finisher phase, birds fed 50% yellow cassava grits diet had the highest (P < 0.05) final weight and weight gain (2235.60 and 1454.00g/bird), respectively while the least final weight and weight gain values (2008.80 and 1267.80g/birds) were obtained in birds fed the control diet. At the starter phase, birds fed 75% white cassava grits diet had the best (P < 0.05) feed conversion ratio of 2.18, while birds fed 25% yellow cassava grits diet as well as those fed the control diet had the least (P < 0.05) feed conversion ratio of 2.62 and 2.51 respectively. Birds fed 50% yellow as well as those fed 75% yellow cassava grits diets had the highest dry matter and crude fibre digestibility at the starter and finisher phases, respectively. In conclusion the substitution of maize with white cassava grits up to 50% level improved growth performance at the starter phase. However, either white or yellow cassava can be substituted for maize up to 75 % at the finishing phase.

In Côte d'Ivoire, cassava production is carried out by small-scale planters who use very few technical means and local cultivars that are not very productive and susceptible to diseases. The objective of this study is to maximize the recovery of cassava cuttings after planting. To this end, ten substrates of single, double, triple and quadruple composition were made from soil supplemented with sawdust, chicken droppings, carbonized rice husks and NPK 10 18 18 to regenerate dehydrated cassava Bocou 1 and Yavo mini-cuttings. The recovery rate of the mini-cuttings was evaluated as well as the agro-morphological parameters of the seedlings for 21 days. Results showed that the recovery rate was very high on the carbonized rice husk substrate (86.5% in Bocou 1 and 85.5% in Yavo). In addition, the substrates significantly influenced the growth parameters of the seedlings. Thus, the substrate composed of carbonized chicken-bale soil had the highest number of leaves, with 6 leaves per plant in Bocou 1 and 10 leaves in Yavo, with an average height ranging from 10.99 ± 1.22 (Bocou 1) to 20.23 ± 1.16 (Yavo). The results of this study will help orient the actors of the cassava sector towards a new cultivation technique.

SummaryBreeding for high and stable yields is a major objective for cassava breeding programmes. Owing to the simultaneous formation of steins and leaves (source) and storage roots (sink), competition for assimilates implies that there is an optimum leaf area index for yield. This has led to the use of the harvest index as a practical criterion for selection. The optimal harvest index and leaf area index are discussed for selection for stressful environments. A successful strategy for developing high yielding varieties for favourable conditions is presented. Recent information has shown that selection for a slightly larger than optimal leaf area index, and hence greater biomass, can lead to stable yield in both favourable and stressful environments. Moreover, yield levels can be increased by selecting for moderate harvest indices (e.g. 0.5-0.65) and increased biomass. Longer leaf life is an integral part of this selection strategy. These concepts are discussed in detail.James H. Cock y Mabrouk A. El-Sharkawy: Caracteristicas fisiológicas para la selección de la mandioca.

Vector population and weather are critical in virus disease incidence and could be strategic for its management in agriculture. To investigate the influence of whitefly population and weather on Cassava Mosaic Disease (CMD) in cassava, TMS 419 and TME 30572, commonly grown in the state were planted. The varieties were laid out in Randomized Complete Block Design in four replicates and left to natural infection by CMD viruses. At two weeks after planting and fortnightly, whitefly population counts were taken, CMD incidence was estimated and severity scored on 5- point scale. Daily temperature, humidity, wind speed and wind direction were obtained as secondary data. Data were analysed using ANOVA at p=0.05. Whitefly population (18/plant) was significant (P≤0.05) in the first 30 days at 26.9-27.1oC, 42% humidity, 10 Km/hr wind speed and when the wind direction was in the East or North-East. The vector population then declined until the end of experiment. Cassava mosaic incidence changed with whitefly population, humidity and wind speed. Disease incidence in cassava plots was low (3.6%). TME30572 maintained lower disease incidence (3.0%) and severity (2.0) during the study. R2 indicated that 27, 42 and 57% of whitefly population could be explained by temperature, humidity and wind speed, respectively while 4% of the disease incidence could be explained by the whitefly population. The number of CMD infected plants peaked (4%) when population of whitefly was 18/plant, above which the disease reduced at 0.0017 rate per unit change in the vector population. Mosaic disease incidence in cassava plots was influenced by vector population as conditioned by the weather.
 Keywords: Bemisia tabaci, Cassava, Cassava Mosaic Disease, Nigeria, Weather, Whitefly vector

Purpose. The purpose of the article – to assess the technical efficiency of climate adaptation practices on cassava production in two different agro-ecological zones within the study area to know where the climate adaptation practices are more productive. To achieve the main objective of the study, the specific objectives were stated as follows: (a) describe relevant socio-economic characteristics of cassava farmers in southwestern region of Nigeria; (b) assess the influence of the used climate change adaptation strategies on technical efficiency of cassava production in both agro-ecological zones.
 Methodology / approach. The study was carried out in Ekiti, Osun and Oyo State in the southwestern region of Nigeria, where two different agro-ecological zones (AEZ) (rain forest and guinea savannah) were chosen for the study. The study used multi-stage sampling procedures, with well-structured questionnaire, to select 150 cassava producers from each AEZ, making a total of 300 cassava producers for the study. Data analysis was done using descriptive statistics and stochastic frontier production function.
 Results. From the study, it was revealed that cassava farmers in the study area were relatively young, fairly educated, mostly married, well experienced, adequately aware of climate change, but operated on a small scale. The result on the influence of climate adaptation strategies on technical efficiency of cassava production in both rain forest and savannah AEZs within the study area revealed that technical inefficiency existed in cassava production as confirmed by the gamma values of 0.687 and 0.639 in rain forest and savannah respectively
 Originality / scientific novelty. The study has really revealed diverse climate adaptation options available to cassava farmers in order to sustain its production as a means of employment to the unemployed, food consumption and contribution to the national gross domestic product. Studies comparing climate adaptation practices on the technical efficiency of cassava production in different agro-ecological zones in southwestern part of Nigeria are relatively scarce considering the mixture of socio-economic and climate variables to assess technical efficiency of cassava production.
 Practical value / implications. The study has succeeded in identifying key factors that will enables policy makers to formulate a sustained policy framework that would encourage the use of multiple climate adaptation practices by the cassava farmers. To ensure sustainability of cassava production, it is therefore recommended that farmers should use different adaptation strategies to climate change e.g crop diversification, multiple planting dates, land fragmentation, use of improved varieties and off farm income activities that would bring increase in their scale of operation as most of the cassava farmers in the study areas cultivated less than 2 hectares of land for cassava production.

This study aimed at evaluating the contribution of cassava recipe in meeting Recommended Dietary Allowance (RDA) of the under five children for the selected nutrients (protein, fat, iron and zinc) in Mtwara rural district. This was achieved by identifying the common cassava recipes and the consumption pattern by using a 24h dietary recall and Food Frequency Questionnaire (FFQ). Proximate composition, mineral contents and anti-nutrients (cyanide and phytate contents) were also determined. The rate of consumption of a child was computed based on food portion and consumption frequency in a day. The sufficiency of nutrient of cassava recipes was determined on the basis of the quantity of food eaten per day. Computed nutrient intake was evaluated against the RDA of respective nutrient for respective age category. The findings indicate that the contribution of cassava to the RDAs of the respective nutrients were 19.4% for iron, 21% for zinc, 0.527% for fat and 4.26% for protein among the under five children which is extremely low. The anti-nutrient (phytate) content was far above the tolerable level of 25 mg/100g but cyanide was within the acceptable level. The computed Individual Dietary Diversity Score (IDDS) of 2.5 was similarly far below the target IDDS of 5. This implies an extremely poor dietary diversity indicative of very low consumption of food varieties including those of animal origin. It is thus important to develop strategies which encourage and make easy for dietary diversification among community members in order to complement cassava based recipes with readily available foods rich in macro and micronutrients. The strategy should also consider dietary practices such as control of intake of inhibitors e.g. of iron absorption and increase intake of enhancers of absorption in a given meal. These strategies can also include cassava recipe supplementation and fortification.

AbstractPre-harvest operations affect the quality of food products. This study evaluated the impact of age at harvest (AH), cropping system (CS) and variety on the chemical and functional properties of high quality cassava flour (HQCF). Two white-fleshed (TMS 30572 and TMS 98/0505) and three yellow-fleshed (TMS 97/JW2, TMS 01/1371 and TMS 01/1368) cassava varieties planted either as sole crop or intercropped with maize were harvested at 12, 15 and 18 months after planting, and processed into HQCF. Chemical composition (proximate, mineral), physico-chemical properties (pH, total titratable acidity and colour) and functional properties (bulk density, water absorption index, dispersibility, swelling power, solubility index and pasting properties) of HQCF were determined. Data obtained were analysed using general linear model (GLM). AH had a significant (P < 0.05) effect on proximate and mineral composition, functional and physico-chemical properties, peak and breakdown viscosities, and peak time of HQCF. CS significantly (P < 0.05) affected the crude fibre, fat, bulk density, swelling power, mineral composition, and physico-chemical properties (except L* and b*) of HQCF. Variety significantly (P < 0.05) affected the proximate (except moisture) and mineral composition, functional properties, and breakdown viscosity of HQCF. The interactive effect of AH, CS and variety was significant (P < 0.05) on fat, dispersibility, mineral composition, and physico-chemical properties. In terms of carbohydrate content, it is desirable to harvest cassava at 12 months after planting, with TMS 98/0505 being the choice variety. Recommendation of the desirable AH, CS and variety will vary according to the desired quality of the end-products. Age at harvest is the most important single factor affecting the proximate composition and functional properties of HQCF.

<p>La incorporación de los criterios de los usuarios del conocimiento en diferentes eslabones de la cadena producción-consumo ha sido documentada ampliamente en su eslabón primario y con relación al fitomejoramiento. No obstante, la vinculación al proceso de investigación de conceptos procedentes de otros eslabones podría garantizar mejor impacto en la productividad. La presente investigación tuvo dos objetivos: 1) identificar los caracteres preferidos por los usuarios del conocimiento en los diferentes eslabones de la cadena agroindustrial de la yuca y, 2) incorporar dichos caracteres en el diseño de nuevas variedades. Los agricultores e intermediarios evaluaron clones en fincas, los fitomejoradores en el centro de investigación, los procesadores (picadoressecadores) en las plantas de secado y los consumidores de yuca fresca en los hogares. Los diversos criterios y caracteres fueron registrados y codificados a fin de realizar análisis de correspondencia múltiple. Mientras los agricultores hombres lograron una buena diferenciación entre los mejores clones por sus atributos, las mujeres tuvieron menor diferenciaron debido a que utilizaron categorías similares en la mayoría de los caracteres. La correspondencia entre los nueve mejores clones seleccionados por los fitomejoradores en las cinco localidades y sus caracteres asociados, permitió identificar tres grupos de clones con caracteres deseables y dos clones con caracteres no muy deseables. Los caracteres comunes entre los mejores clones evaluados por consumidores de hogar se asociaron con el sabor, el color de la pulpa, la consistencia y el contenido de harina. El análisis de caracteres comunes entre todos los evaluadores indicó que un eje lo determinaron los consumidores y el otro los fitomejoradores. Los resultados permitieron concluir que un contenido alto de almidón fue el rasgo más determinante en la selección de un buen clon para secado natural; para los almidoneros, la relación yuca fresca/almidón seco y el color blanco de la cutícula fueron los rasgos más importantes. Finalmente, se identificaron caracteres comunes entre procesadores, consumidores, investigadores, agricultores hombres y agricultores mujeres. </p><p> </p><p><strong>Identification of preferred traits of cassava varieties by users in the production-consumption chain at the Colombian Caribbean region</strong></p><p>The incorporation of end-user criteria in different links of the production-consumption chain has been broadly documented in the first link and with relation to plant breeding. However incorporating concepts in the research process from other links could guarantee a greater impact on productivity. The purpose of this research was two fold: 1) to identify preferred knowledge users characteristics in the different links of the cassava agrochain, and 2) to incorporate these traits in the design of new varieties. Evaluation of cassava clones was done by farmers and middlemen on farms, plant breeders evaluated at research centers, processors evaluated at chipping and drying plants and fresh cassava consumers at the household level. Through open interview, diverse opinions and traits were recorded and encoded to perform a multiple correspondence analysis. While male farmers achieved a proper differentiation between the best clones by their characteristics, women had less differentiation because they used more similar categories for most traits. At five localities, plant breeders’ selection of the best nine clones and their associated characters allowed for the identification of three groups of clones with desirable traits and two clones with undesirables characteristics. Common traits among the best clones evaluated by household consumers were associated with taste, pulp color, consistency and starch content. Analyses of common traits among all evaluators indicated that one axis was established by consumers and another by plant breeders. The results indicated that high starch content was the determining feature in clone selection for natural dryers, while for starch producers the most important traits were fresh weight/dry starch ratio and white skin color. At the end, common criteria were identified among dryers, household consumers, researchers and farmers gender. </p>

Mainland Southeast Asia (MSA) has seen sweeping upland land use changes in the past decades, with transition from primarily subsistence shifting cultivation to annual commodity cropping. This transition holds implications for local upland communities and ecosystems. Due to its particular political regime, Myanmar is at the tail of this development. However, with Myanmar’s official strategy of agricultural commercialization and intensification, recent liberalization of the national economy, and influx of multinational agricultural companies, the effects on upland land transitions could come fast. We analyze the current state of upland land use in Myanmar in a socio-economic and political context, identify the dynamics in three indicator commodity crops (maize, cassava, and rubber), and discuss the state driven economic, tenurial and policy reforms that have occurred in upland areas of mainland Southeast Asian countries in past decades. We draw on these insights to contextualize our study and hypothesize about possible transition pathways for Myanmar. The transition to annual commodity cropping is generally driven by a range of socio-economic and technical factors. We find that land use dynamics for the three indicator crops are associated with market demand and thus the opening of national Southeast-Asian economies, research and development of locally suitable high yielding varieties (HYVs), and subsidies for the promotion of seeds and inputs. In contrast, promotion of HYVs in marginal areas and without adequate agricultural extension services may results in agricultural contraction and yield dis-intensification. The environmental impacts of the transition depend on the transition pathway, e.g., through large-scale plantation projects or smallholder initiatives. The agricultural development in upland MSA follows a clear diffusion pattern with transition occurring first in Thailand, spreading to Vietnam, Cambodia and Laos. While these countries point to prospects for Myanmar, we hypothesize that changes will come slow due to Myanmar’s sparse rural infrastructure, with uncertainty about tenure, in particular in areas still troubled by armed conflicts, and unwillingness of international investors to approach Myanmar given the recent setbacks to the democratization process.

Achieving food security for an ever-increasing human population requires faster development of improved varieties. To this end, assessment of genetic gain for key traits is important to inform breeding processes. Despite the improvements made to increase production and productivity of cassava in Uganda at research level, there has been limited effort to quantify associated genetic gains. Accordingly, a study was conducted in Uganda to assess whether or not genetic improvement was evident in selected cassava traits using cassava varieties that were released from 1940 to 2019. Thirty-two varieties developed during this period, were evaluated simultaneously in three major cassava production zones; central (Namulonge), eastern (Serere), and northern (Loro). Best linear unbiased predictors (BLUPs) of the genotypic value for each clone were obtained across environments and regressed on order of release year to estimate annual genetic gains. We observed that genetic trends were mostly quadratic. On average, cassava mosaic disease (CMD) resistance increased by 1.9% per year, while annual genetic improvements in harvest index (0.0%) and fresh root yield (−5 kg per ha or −0.03% per ha) were non-substantial. For cassava brown streak disease (CBSD) resistance breeding which was only initiated in 2003, average annual genetic gains for CBSD foliar and CBSD root necrosis resistances were 2.3% and 1.5%, respectively. It’s evident that cassava breeding has largely focused on protecting yield against diseases. This underpins the need for simultaneous improvement of cassava for disease resistance and high yield for the crop to meet its current and futuristic demands for food and industry.

Orientador: Sílvio José Bicudo<br>Banca: Teresa Losada Valle<br>Banca: José Carlos Feltran<br>Banca: Marina Aparecida de Moraes Dallaqua<br>Banca: Ricardo Augusto Dias Kanthack<br>Resumo: A poda da parte aérea da mandioca é prática comum nos cultivos comerciais destinados à industrialização. Vem sendo praticada principalmente por possibilitar o controle das plantas infestantes com herbicidas no segundo ciclo vegetativo. Seus efeitos no desenvolvimento das plantas e na produtividade de raízes de mandioca ainda não são claros e resultados controversos são encontrados na literatura. Com o objetivo de estudar os efeitos da poda foram realizados seis experimentos, em dois ambientes: Botucatu, experimentos 1, 3 e 5 e em São Manuel, experimentos 2, 4 e 6. Os experimentos 1 e 2 tiveram como causas de variação cinco variedades de mandioca cultivadas com e sem poda. Os experimentos 3 e 4 avaliaram nove épocas de poda frente a uma testemunha conduzida sem poda. Os experimentos 5 e 6 tiveram como causas de variação quatro densidades de plantio avaliadas com e sem poda. Concluiu-se que: a poda altera a produtividade de matéria seca de raízes de maneira distinta considerando a variedade e o ambiente; a poda anterior ao período de repouso fisiológico ou após o início do segundo ciclo vegetativo reduz a produtividade de matéria seca de raízes; em altas densidades de plantio, a poda reduz de maneira significativa a produtividade de matéria seca de raízes. Desse modo, a poda da parte aérea da mandioca não deve ser recomendada de maneira genérica, devendo considerar entre outros, os fatores avaliados no presente estudo<br>Abstract: Cassava pruning is common in commercial crops destined for industrialization, a practice mainly aimed at enabling weed control with herbicides in the second growth cycle. Its effects on plant development and cassava yields remain unclear and controversial results are reported in the literature. With the objective of studying the effects of pruning, six experiments were conducted in two environments: in Botucatu, experiments 1, 3 and 5, and in São Manuel, experiments 2, 4 and 6. In experiments 1 and 2, the established variables were five varieties of cassava cultivated with and without pruning. Experiments 3 and 4 evaluated nine pruning dates compared with control cultivated without pruning. The established variables in experiments 5 and 6 were four planting densities, evaluated with and without pruning. It can be concluded that: cassava pruning causes distinct alterations in the productivity of dry root matter, depending on the variety and culture environment; pruning before or after the period of physiological rest or after the onset of the second growth cycle reduces the productivity of dry root matter; and pruning in high planting densities significantly reduces the productivity of dry root matter. Thus, cassava pruning cannot be recommended as a general practice, as currently occurs, and the factors evaluated in this study should be taken into consideration<br>Doutor