Physiological Causes Of Yield Variation In Cassava Manihot Esculenta Crantz

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Physiological Causes Of Yield Variation In Cassava Manihot Esculenta Crantz

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Author : H. J. Veltkamp
language : en
Publisher:
Release Date : 1986

Physiological Causes Of Yield Variation In Cassava Manihot Esculenta Crantz written by H. J. Veltkamp and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1986 with Gardening categories.

This thesis begins with a literature review in which the available information on the physiological determinants of the yield of cassava storage roots is described.

Cassava

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Author : R. J. Hillocks
language : en
Publisher: CABI
Release Date : 2002

Cassava written by R. J. Hillocks and has been published by CABI this book supported file pdf, txt, epub, kindle and other format this book has been release on 2002 with Technology & Engineering categories.

Cassava is a major tropical tuber crop found throughout the tropics (India, Oceania, Africa and Latin America). Hitherto, there has been no single text covering all aspects of cassava biology, production and utilization. This book fills that gap, representing the first comprehensive research level overview of this main staple crop. Chapters are written by leading experts in this field from all continents. The book is suitable for those working and researching in cassava, in both developed and developing countries, as well as advanced students.

Towards Identifying The Physiological And Molecular Basis Of Drought Tolerance In Cassava Manihot Esculenta Crantz

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Author : Rosemary Wanja Mutegi-Murori
language : en
Publisher: Cuvillier Verlag
Release Date : 2010-02-10

Towards Identifying The Physiological And Molecular Basis Of Drought Tolerance In Cassava Manihot Esculenta Crantz written by Rosemary Wanja Mutegi-Murori and has been published by Cuvillier Verlag this book supported file pdf, txt, epub, kindle and other format this book has been release on 2010-02-10 with Science categories.

Drought is one of the most important factors limiting crop production in sub-Saharan Africa. This has detrimental effects to the people living in this region, and whose population is increasing more rapidly than their domestic food production. Noticeably, pressure on agricultural land has continued to intensify. Cassava is one of the staple crops with remarkable tolerance to drought. It is adapted to diverse and poor soil conditions, in addition to its flexibility in planting and harvesting times. Understanding its physiological and molecular basis of drought tolerance may help to target the key traits that limit crop yield under drought conditions. To improve our understanding on drought tolerance mechanisms in cassava, the project "Identifying the physiological and genetic traits that make cassava one of the most drought-tolerant crops" was initiated in 2005 by the Brazilian Agricultural Research Corporation (Embrapa) in collaboration with the International Center for Tropical Agriculture (CIAT); the International Institute of Tropical Agriculture (IITA); Cornell University and University of Goettingen. The ultimate goal of the project was to identify morphological, physiological and molecular traits related to drought tolerance mechanisms in cassava for further progress, and for their application in cassava and other crop breeding programs. The present study was conducted within the framework of this project with 31 African cassava germplasm accessions from IITA and a mapping population developed at CIAT. The objectives of this study were, 1) To develop a protocol for hardening and rapid micro-propagation of cassava plantlets under local, low-cost conditions; 2) To identify agro-morphological attributes that are related to drought tolerance in cassava; 3) To identify drought-tolerant and drought-susceptible cassava germplasm from a selection of African accessions; 4) To identify secondary traits that could be used for phenotyping breeding materials for drought tolerance; 5) To screen the CIAT mapping population with simple sequence repeats (SSR) and expressed simple sequence repeat (ESSR) markers for linkage analysis. Thirty one putative drought-tolerant and drought-susceptible African cassava germplasm accessions from IITA were micro-propagated using direct and in-direct techniques, at Kenya Agricultural Research Institute (KARI), Nairobi, Kenya. In direct micro-propagation, plantlets were hardened using vermiculite and multiplied through nodal cuttings. In in-direct micro-propagation, plantlets were first multiplied through sub-culturing and later hardened. The direct micro-propagation method had a higher multiplication rate. The number of plantlets obtained in 7 months using the direct method were 1173 as compared to 722 attained using the in-direct micropropagation. Rapid micro-propagation through nodal cuttings was cheaper in terms of consumables and an effective alternative to enhance rates of multiplication, over the in-direct method and the more conventional technique like the use of stem cuttings. Agronomic and morphological evaluation of contrasting African cassava germplasm accessions was carried out in water-stressed and well-watered environments at 5 time points. The trial was conducted at the experimental field of KARI, Kiboko Research Station in Makindu, Eastern Kenya, a site characterized by Acri-orthic Ferralsol soil. Analysis of variance was performed using the agronomic and morphological data, and broad sense heritability was estimated. In general, significant differences were observed among the accessions, suggesting a strong genetic basis for the phenotypic variation observed. Variation was also notable in water-stressed and well-watered environments for a majority of traits evaluated. This was due to the artificial water applied since, during the trial period, there was hardly any rainfall. At harvest, leaf length and width of certain accessions at the water-stressed site approached that of the well-watered treatment. On average, the estimated mean percentage leaf retention was high in the well-watered treatment. However, leaf retention in some of the accessions assessed was almost the same in both treatments. These accessions tended to produce higher yields. Thus, it may be desirable to select for higher leaf retention when developing varieties adapted to dry areas. The range of yields under stress was from 3.3 to 36.7 kg/m2, whereas, under the well-watered treatment, it was smaller: 28.3 to 53.3 kg/m2. Differences among accessions in yield and overall above-ground fresh biomass showed that these are important primary traits to phenotype germplasm under favorable and water-stress conditions. In addition, 4 accessions G26, G11, G8 and G31 were more tolerant than the rest of the genotypes evaluated, calling for further research and their involvement in agricultural experimentation under drought-prone conditions. Considering relationships between traits, genotype ability for both accumulation of above-ground fresh biomass and to partition carbon into roots (harvest index) were among the traits most correlated with root yield. However, accessions, environment and the interaction of both influenced the traits strongly. Thus, it is important that agro-morphological field trials be conducted in several locations for several seasons for effective evaluation of their influences on traits that might be relevant for phenotypically assessing drought tolerance. Unlike for agro-morphological traits, where a drought-tolerant accession could be identified from the yield, which is of primary concern, selection of an outstanding accession in a water-limited environment using metabolic traits was not achieved in this study. Maybe the well-watered plants experienced an incipient stress due to low humidity, symptomless diseases or nutrient deficiency, which was not ascertained in this study. Despite this, significant differences were observed between the waterstressed and well-watered treatments for the traits evaluated, except protein and amylose content. Performance in individuals was variable, although insignificant differences were observed between the different stress phases. Changes in sugar concentration have a role in the drought-tolerance of the accessions evaluated, although, their relative contribution to drought stress could not be determined from the available data. Further work is imperative to identify and quantify sugar concentrations in relation to osmotic adjustment in these accessions. In addition, further research to determine the time course of ABA accumulation, as a cassava plant goes from its young stage to aging, is required so as to know the stage at which ABA data are most informative. Two genetic linkage maps were constructed using a South American mapping population of 228 individuals derived from a cross between a drought-tolerant and a drought-susceptible parent. A set of 377 simple sequence repeats (SSR) and expressed simple sequence repeats (ESSR’s) were utilized for the initial polymorphism screening. Differences in map size, interval, number and mean distance between markers were apparent between the two maps. The female map had 14 linkage groups as compared to 13 in the male map. Twenty seven allelic bridges were noticeable between the two maps. In addition, 25 markers showed collineality with other available cassava maps. Forty six markers, whose map distances had not been determined previously, were mapped in this study. These maps form an important platform upon which to characterize the genetic basis of drought tolerance in cassava. Continued addition of more markers in these maps will refine the utility of the resource for future cassava breeding efforts. In conclusion, four African cassava accessions apparently have the ability to withstand severe drought. However, a majority of the accessions evaluated gave poor response in adaptability to water-limited conditions. This suggests that further agroecologically based research is required on these materials, since they represent diverse improved accessions from IITA breeding activities. This, coupled with markerassisted genetic analysis, would be an appropriate approach for the identification of drought-tolerant accessions.

Cassava

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Author : Andri Frediansyah
language : en
Publisher: BoD – Books on Demand
Release Date : 2021-09-01

Cassava written by Andri Frediansyah and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2021-09-01 with Technology & Engineering categories.

Cassava is a staple crop in a large number of countries due to its adaptability to a variety of climatic conditions. It has spread extensively throughout Latin America, tropical Asia, and Sub-Saharan Africa. Cassava, which is well known for its high carbohydrate content, is the third most carbohydrate-rich food after rice and maize. This book discusses the diversity of cassava and its microbiome, cassava cultivation and postharvest practices, as well as crop yield-reducing diseases. Due to its widespread use and market importance, cassava has been subjected to biological and technological intervention to ensure food safety. This book will help readers to gain knowledge about cassava, its biological properties, and some of the strategies and procedures necessary to increase cassava crop output.

Growth Physiology Of Cassava

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Author : L. A. Hunt
language : en
Publisher:
Release Date : 1977

Growth Physiology Of Cassava written by L. A. Hunt and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1977 with Cassava categories.

Studies On Cassava Manihot Esculenta Crantz Root Post Harvest Physiological Deterioration

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Author : Christopher Charles Wheatley
language : en
Publisher:
Release Date : 1982

Studies On Cassava Manihot Esculenta Crantz Root Post Harvest Physiological Deterioration written by Christopher Charles Wheatley and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1982 with categories.

These studies demonstrated that the principal factors controlling the susceptibility of cultivars to physiological deterioration are environmental: plants defoliated due to severe stresses were markedly more resistant than non-defoliated plants of the same cultivar. Site and prevailing pre-harvest environmental conditions also affected the degree of susceptibility. Pruning experiments gave results which closely agreed with the defoliation effects and confirmed reports that pre-harvest pruning induced resistance to physiological deterioration. Such induced resistance was maintained for at least nine weeks after pruning and was unaffected by subsequent regenerative growth. A reduction in root dry matter content occurred following pruning but this was not causally related to resistance to physiological deterioration.

Abstracts On Cassava Manihot Esculenta Crantz

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Author :
language : en
Publisher:
Release Date : 1985

Abstracts On Cassava Manihot Esculenta Crantz written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 1985 with Cassava categories.

Cassava

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Author : Viduranga Waisundara
language : en
Publisher: BoD – Books on Demand
Release Date : 2018-01-17

Cassava written by Viduranga Waisundara and has been published by BoD – Books on Demand this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018-01-17 with Science categories.

Cassava is a staple food for many nations owing to its resilience for growth under various climatic conditions. It is a good source of carbohydrates and is the third largest source of food carbohydrates in the tropics, after rice and maize. This book focuses on the morphological traits and nutritive properties of cassava and its production processes, postharvest techniques and diseases that affect the growth of the crop. Given its extensive usage and market value, it is one of the agricultural produces for which many biotechnological interventions have been applied for ascertaining food security. It is hoped that readers will gain knowledge on cassava as well as use some of the techniques mentioned herein for improvement of the production of the crop.

Crop Physiology Case Histories For Major Crops

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Author : Victor Sadras
language : en
Publisher: Academic Press
Release Date : 2020-12-05

Crop Physiology Case Histories For Major Crops written by Victor Sadras and has been published by Academic Press this book supported file pdf, txt, epub, kindle and other format this book has been release on 2020-12-05 with Technology & Engineering categories.

Crop Physiology: Case Histories of Major Crops updates the physiology of broad-acre crops with a focus on the genetic, environmental and management drivers of development, capture and efficiency in the use of radiation, water and nutrients, the formation of yield and aspects of quality. These physiological process are presented in a double context of challenges and solutions. The challenges to increase plant-based food, fodder, fiber and energy against the backdrop of population increase, climate change, dietary choices and declining public funding for research and development in agriculture are unprecedented and urgent. The proximal technological solutions to these challenges are genetic improvement and agronomy. Hence, the premise of the book is that crop physiology is most valuable when it engages meaningfully with breeding and agronomy. With contributions from 92 leading scientists from around the world, each chapter deals with a crop: maize, rice, wheat, barley, sorghum and oat; quinoa; soybean, field pea, chickpea, peanut, common bean, lentil, lupin and faba bean; sunflower and canola; potato, cassava, sugar beet and sugarcane; and cotton. A crop-based approach to crop physiology in a G x E x M context Captures the perspectives of global experts on 22 crops

Wheat Growth And Modelling

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Author : W. Day
language : en
Publisher: Springer
Release Date : 1985-05-01

Wheat Growth And Modelling written by W. Day and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 1985-05-01 with Science categories.

The concept of using mathematical models to investigate crop growth and productivity has attracted much attention in recent years. A major reason is that modelling can allow an expert in one area to assess the impact of his ideas in the light of other advances in our understanding of crop performance. Whether or not many of the claims made for or the demands made of models can ever be satisfied, this role as a focus for quantitative definition of crop growth is an important one. One consequence is that the development and appraisal of such models requires the efforts of scientists from a wide range of disciplines. This NATO Advanced Research workshop was designed to bring together such a range of scientists to consider the wheat crop, and assess our understanding of the crop and our ability to model its growth and yield. The ideas and organization behind the workshop involved many people. The U. K. interest in a computer model of wheat growth was instigated by Dr. Joe Landsberg (then of Long Ashton Research Station, but now Director of CSIRO Division of Forest Research), who in 1979 started a modelling exercise as part of a collaborative study of the causes of yield variation in winter wheat, involving four research institutes supported by the Agricultural and Food Research Council. Dr.