Drought-tolerant Cassava for Africa, Asia, and Latin America

El‐Sharkawy, Mabrouk A.

doi:10.2307/1311903

Cited by 151 publications

(166 citation statements)

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“…Comportamiento manifestado a causa del estímulo ejercido por la poca disponibilidad de agua sobre el mecanismo de respuesta fisiológica propio que exhibe la planta de yuca. Adicionalmente, se han encontrado resultados similares, donde inicialmente, la planta de yuca se auto regulo, efectuando un uso más eficiente del recurso hídrico, continuando con una reducción en el crecimiento de los diferentes órganos de la planta, que se traduce en una disminución en la acumulación de biomasa; la cual se interrumpe al reestablecerse las condiciones hídricas necesarias para el óptimo desarrollo del cultivo (EL SHARKAWY, 1993;CAYÓN et al, 1997). Exhibiendo en esta etapa post-stress una tendencia positiva sobre la formación de hojas nuevas con tasas de fotosíntesis más altas, que permiten una recuperación rápida de los materiales afectados, expresado en un incremento del índice de área foliar coincidiendo con lo reportado por CHEN et al (1997).…”

Section: A N T I D a D D E R A M I F I C A C I O N E S ( C R )unclassified

Arquitectura del dosel en yuca (Manihot esculenta Crantz) en el bosque seco tropical en Colombia

2017

Rev Colombiana Cienc Anim. RECIA

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The objective of the research was evaluated the influence of soil availability on the architecture of cassava canopy. The work was carried out in the tropical dry forest area of the state of Sucre, Colombia. Experimental plots were established in October 2015, records of plant height, number of branches, foliar insertion angle and branching at twelve months of age, low experimental design in randomized complete blocks, with factorial arrangement . As fixed factors the cassava variety (MCOL 2066, CM 4919-1, SM 1411 and SM 2775) and irrigation (complementary irrigation and without complementary irrigation) were produced. Foliar insertion patterns favored by the absence of irrigation were found, being these of type plagiófilos in the superior third and planificadores in the middle and inferior thirds, what allows greater efficiency in the capture of the radiation. The height of the plant was influenced by the water supply, evidencing the superior growth around 17.9% under the use of a sheet of 17 millimeters of irrigation during the first months of the crop growth. The irrigation factor promotes in a differentiated way the architectural response of the canopy. Keywords:Genotypes; Insertion angle; variety; branching. ResumenEl objetivo de la investigación fue evaluar la influencia de la disponibilidad hídrica del suelo sobre la arquitectura del dosel de yuca. El trabajo se realizó en la zona de bosque seco tropical del departamento de Sucre, Colombia. Las parcelas experimentales se establecieron en octubre de 2015, registrándose datos de altura de planta, cantidad de ramificaciones, ángulo de inserción foliar y de ramificación a los doce meses de edad, bajo un diseño experimental en bloques completos al azar, con arreglo factorial. Como factores fijos se tuvo la variedad de yuca (MCOL 2066, CM 4919-1, SM 1411 y SM 2775) y el riego (riego complementario y sin riego complementario). Se encontraron patrones de inserción foliar favorecidos por la ausencia de riego, siendo estos de tipo plagiófilos en el tercio superior y planófilos en los tercios medio e inferior, lo que permite mayor eficiencia en la captura de la radiación. La altura de planta fue influenciada por la oferta hídrica, evidenciando superior crecimiento en alrededor de 17,9% bajo la aplicación de una lámina de 17 mm de riego durante los primeros meses de crecimiento del cultivo. El factor riego promueve de forma diferenciada la respuesta arquitectónica del dosel. Palabras Clave:Ángulo de inserción; ramificación; altura de planta.Arquitectura del dosel en yuca (Manihot esculenta Crantz) en el bosque seco tropical en Colombia

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Section: A N T I D a D D E R A M I F I C A C I O N E S ( C R )unclassified

Arquitectura del dosel en yuca (Manihot esculenta Crantz) en el bosque seco tropical en Colombia

2017

Rev Colombiana Cienc Anim. RECIA

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“…However, most of the increases in cassava production have been due to cropland expansion, rather than increases in yield per hectare, as the area under production has increased by 70% in the last two decades (Hillocks, 2002). Presently, as cassava cultivation is expanding into non-traditional areas such as semi-arid regions of sub-saharan Africa (El-Sharkawy, 1993), efforts to develop high yielding and drought tolerant varieties are being advocated (El-Sharkawy, 1993, 2006Hillocks, 2002;Nweke, 2004). For food security and environmental sustainability, future increase in cassava production should be based on alternative options other than expansion of cultivated lands as currently practised.…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have shown that cassava responds to drought by closing its stomata apparatus to reduce transpiration, which acts to protect leaf tissues from turgor loss and desiccation (Connor and Palta, 1981;ElSharkawy and Cock, 1984;El-Sharkawy et al, 1992;El-Sharkawy, 1993;Alves and Setter, 2000). Reductions in apparent photosynthesis and leaf transpiration have also been attributed to decreases in leaf conductance in response to increasing humidity deficit under well-watered and stressed conditions in potted plants grown outdoors as well as in field-grown crops (ElSharkawy and Cock, 1984;El-Sharkawy, 1990, 2006De Tafur et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Environmental regulation and modelling of cassava canopy conductance under drying root‐zone soil water

Oguntunde

Alatise

2007

Meteorological Applications

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Sap flow was measured, with Granier-type sensors, in a crop of field-grown water-stressed cassava (Manihot esculenta Crantz) in Ghana, West Africa. The main objective of this study was to examine the environmental control of canopy conductance (g c ) with a view to modelling the stomatal control of water transport under water-stressed condition. Weather variables measured concurrently with sap flow were: air temperature (T a ), relative humidity (RH ), wind speed (u) and solar radiation (R s ). Relationship between canopy conductance (g c ) and vapour pressure deficit (D ε ) was curvilinear while no specific pattern was observed with R s . Average diurnal g c decreased from 3.0 ± 0.6 to 0.7 ± 0.4 mm s −1 between 0730 and 2000 h local time (= GMT) each day. A Jarvis-type model, based on a set of environmental control functions, was parameterized for the cassava crop in this study. Model results demonstrated that g c was estimated with a high degree of accuracy based on R s , T a , and D ε (r 2 = 0.92; F = 809.2; P < 0.0001). D ε explained about 90% (F = 2129.7; P < 0.0001) of the variations observed in g c , whereas both R s and T a contributed about 2% of the explained variance in g c . The aerodynamic conductance (g a ) was very high compared to g c , leading to a daily average ratio g a /g c > 100 and a decoupling factor< 0.1. Cross-validation analysis revealed a consistent good performance (r 2 > 0.85) of the g c model with D ε as the only independent environmental variable.

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“…Moreover, it is known that there is sufficient genetic diversity in the cassava genebanks that can be explored for this trait (Iglesias et al 1997, Carvalho 2000. The inheritance for b-carotene concentration in cassava roots is controlled by few genes, i.e., the levels of b-carotene in cassava varieties can be improved through genetic improvement (Iglesias et al 1997).Although cassava contributes to ensure the food security of poor rural communities, little is known about the variability in nutritional and quality traits of the roots (Chavez et al 2005) Since the crop grows well under harsh conditions, and such areas are increasing worldwide (El-Sharkawy 1993), this issue should not be overlookedThe objective of this study was to analyze the genetic variability of 30 yellow-orange root cassava accessions of the Cassava Genebank of Embrapa Cassava and Tropical Fruits using RAPD markers. This study is a first step towards the establishment of cassava improvement strategies to raise the b-carotene content in new cassava varieties, so that superior genotypes can be made available for farmers and later be released as new, b-carotene-rich cassava varieties.…”

mentioning

confidence: 99%

“…Although cassava contributes to ensure the food security of poor rural communities, little is known about the variability in nutritional and quality traits of the roots (Chavez et al 2005) Since the crop grows well under harsh conditions, and such areas are increasing worldwide (El-Sharkawy 1993), this issue should not be overlooked…”

mentioning

confidence: 99%

Molecular characterization of Cassava (Manihot esculenta Crantz) with yellow-orange roots for beta-carotene improvement

Ferreira¹,

Alves²,

Pestana³

et al. 2008

CBAB

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-Casssava (Manihot esculenta Crantz) is one of the main food and income sources of about 500 million people in the tropics. The crop is mainly cultivated by small farmers in tropical Africa, Asia and Latin America. Embrapa Mandioca e Fruticultura Tropical, based in Cruz das Almas, Bahia, maintains one of the largest cassava genebanks of Latin America. Among the accessions it contains, those with yellow-orange root color are particularly interesting. The objective of this study was to characterize 30 cassava accessions with yellow-orange root color by RAPD markers. The genetic distances of the 47 analyzed primers varied from 9.0 to 31.7 %, demonstrating the existing genetic variability to be exploited for the development of cassava varieties with higher beta-carotene contents.Molecular characterization of Cassava ( Molecular characterization of Cassava ( Molecular characterization of Cassava ( Molecular characterization of Cassava ( Molecular characterization of Cassava (Manihot esculenta Crantz Crantz Crantz Crantz Crantz) ) ) ) ) with yellow-orange roots for beta-carotene with yellow-orange roots for beta-carotene with yellow-orange roots for beta-carotene with yellow-orange roots for beta-carotene with yellow-orange roots for beta-carotene improvement improvement improvement improvement improvement In Brazil, 4132 accessions have been collected and are maintained in genebanks across the country (Fukuda 2000). Carotenes (-carotene, b-carotene, lycopene) represent the most multifaceted group of pigments in nature, with colors varying from yellow to red, found in photosynthetic and non-photosynthetic tissues, such as roots, seeds and fruits. Once ingested, b-carotene is transformed, in the liver, into Vitamin A. Vitamin A is a micro-nutrient with functions related to vision, cell differentiation, growth development, reproduction and the immune system. Vitamin A deficiency (VAD) can cause severe diseases, e.g., ocular syndrome, xerophthalmia, and advance to irreversible blindness (Underwood et al. 1999). Although the lack of vitamin A can be prevented, xerophthalmia is still a public health problem in many developing countries (Welch and Graham 2002). In general, staple foods are considered poor sources of micro-nutrients. Cassava genetic breeding may modify this situation, through the exploration of diversity encountered in yellow-orange root cassava accessions (Gregorio 2002, Welch 2002, Bedoya et al. 2003. Among the accessions of the Cassava Genebank of Embrapa Cassava and Tropical Fruits, those with yellow-orange roots, which have only recently become the subject of thorough studies, deserve special attention. The roots of these accessions possibly contain high b-carotene contents. Moreover, it is known that there is sufficient genetic diversity in the cassava genebanks that can be explored for this trait (Iglesias et al. 1997, Carvalho 2000. The inheritance for b-carotene concentration in cassava roots is controlled by few genes, i.e., the levels of b-carotene in cassava varieties can be improved thr...

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Drought-tolerant Cassava for Africa, Asia, and Latin America

Cited by 151 publications

References 38 publications

Arquitectura del dosel en yuca (Manihot esculenta Crantz) en el bosque seco tropical en Colombia

Arquitectura del dosel en yuca (Manihot esculenta Crantz) en el bosque seco tropical en Colombia

Environmental regulation and modelling of cassava canopy conductance under drying root‐zone soil water

Molecular characterization of Cassava (Manihot esculenta Crantz) with yellow-orange roots for beta-carotene improvement

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