Role Of Cassava Research Articles

Key factors influencing food security of smallholder farmers in Tanzania and the role of cassava as a strategic crop

Due to beneficial characteristics of cassava such as robustness and versatility for multiple uses, it can have a major role in contributing to local food security. The objective of this study was to find out whether and how the cultivation of cassava benefits smallholder farmers in the regions of Dodoma and Morogoro, Tanzania. In addition, the study assessed the main factors that support or threaten food security of smallholder farmer households in the survey region and analysed whether cassava cultivation could counteract them. We applied a mixed methods approach. Quantitative data were provided by a comprehensive household survey of the Trans-SEC project, and qualitative data were collected by conducting semi-structured interviews. To approach the complexity of our chosen food security definition, three approaches for household food security measurement were applied. These covered the components of food availability, food access, and food utilization. Additionally, dependent variables for regression models were constructed and a multivariate analysis was run. The results show that cassava contributes to food security in the households, but achieving food security through cassava cultivation was constrained by several factors, including pests, missing markets, poor processing, social perception and lack of knowledge. Besides these, other factors affecting food security in the study area were found, uncovering some roots of local food insecurity and serving as a basis for further research and action on how to enhance food security.

Yield Improvement in a Multistage Breeding Program for Cassava

The role of cassava (Manihot esculenta Crantz) is rapidly changing from a traditional fresh human food commodity to an efficient crop for agro-industrial processing in many parts of Asia. Varietal improvement for higher yield and root dry matter content is bringing additional cash income to a great number of small farmers. We documented the yield component data of breeding populations through five evaluation stages with and without selection. We define a best selection scheme based on the genetic, interaction, and error parameters obtained. Important conclusions are (i) broad-sense heritability and phenotypic correlations obtained at a given selection stage may lead to erroneous selection schemes, (ii) regression across evaluation stages gives the most useful information, (iii) in early evaluation stages, eliminating inferior phenotypes is more beneficial than selecting superior phenotypes, (iv) selection for root dry matter content can be conducted without serious effects on other yield components, (v) harvest index has consistently high heritability at each evaluation stage, while biomass and yield have low heritability, (vi) genotype × evaluation stage interaction for yield is greatest between single-row and plot trials, while that of harvest index is much smaller [selection at single-row trials (SRT), usually the second stage of evaluation, is most crucial to the final success of selection for higher yield], and (vii) indirect selection for yield through harvest index is more effective than direct selection by yield itself especially in the early evaluation stages. Realized selection confirmed the conclusions. Actual cultivar dissemination testifies the usefulness of this methodology.

Infestation of dried cassava ( Manihot esculenta Crantz) by Prostephanus truncatus (Horn( (Coleoptera: Bostrichidae)

Stored dried cassava is known to become heavily infested by Prostephanus truncatus (Horn). A field study was undertaken in Tanzania to determine the extent of losses that this pest could cause in fermented and unfermented dried cassava roots stored over a period of about 4 months. In fermented roots, the mean weight loss (±SD) rose to 73.6 ± 25.9% over this period compared with 52.3 ± 12.0% in unfermented roots. At each time interval that roots were examined, the weight loss in fermented roots was significantly higher. Subsequent laboratory studies, undertaken to identify some of the factors responsible for this difference between the two types of cassava comprised (1) a determination of the length of larval and pupal development at 27°C and 50 or 70% r.h., (2) adult preference for the two types, and (3) their susceptibility to adult boring. P. truncatus developed at a similar rate in both fermented and unfermented roots, but the adults appeared to prefer the fermented cassava possibly because it was easier to bore into. This was certainly one factor making fermented roots more susceptible to damage by adults. It is concluded that although P. truncatus caused lower weight loss in the unfermented compared with the fermented roots, both were so heavily damaged that it is not worth recommending the storage of one rather than the other. The role of cassava as an intermediate host for P. truncatus is discussed and consideration is given to the need to control the beetle in cassava in order to reduce cross-infestation to maize.