Research Topics

EPAR Technical Report #310
Publication Date: 11/20/2015
Type: Literature Review
Abstract

Cereal yield variability is influenced by initial conditions such as suitability of the farming system for cereal cultivation, current production quantities and yields, and zone-specific potential yields limited by water availability. However, exogenous factors such as national policies, climate, and international market conditions also impact farm-level yields directly or provide incentives or disincentives for farmers to intensify production. We conduct a selective literature review of policy-related drivers of maize yields in Ethiopia, Kenya, Malawi, Rwanda, Tanzania, and Uganda and pair the findings with FAOSTAT data on yield and productivity. This report presents our cumulative findings along with contextual evidence of the hypothesized drivers behind maize yield trends over the past 20 years for the focus countries.

EPAR Research Brief #312
Publication Date: 07/30/2015
Type: Literature Review
Abstract

This brief reviews the evidence of realized yield gains by smallholder farmers attributable to the use of high-quality seed and/or improved seed varieties. Our analysis suggests that in most cases, use of improved varieties and/or quality seed is associated with modest yield increases.  In the sample of 395 trials reviewed, positive yield changes accompanied the use of improved variety or quality seed, on average, in 10 out of 12 crops, with rice and cassava as the two exceptions.

EPAR Technical Report #302
Publication Date: 04/29/2015
Type: Literature Review
Abstract

The review consists of a summary of the emergence of agribusiness clusters, SEZs and incubators since 1965 (with a focus on smallholder agriculture-based economies in Latin America, Africa, and Asia), followed by a series of brief case studies of example programs with particular relevance for guiding proposed clusters/incubators in the countries of Ethiopia, Tanzania, Nigeria and the Eastern Indian states of Uttar Pradesh, Bihar, and Odisha. Summary conclusions draw upon published reports and primary analysis of case studies to highlight apparent determinants of success and failure in agribusiness investment clusters and incubators, including characteristics of the business environment (markets, policies) and characteristics of the organizational structure (clusters, accelerators) associated with positive smallholder outcomes. 

EPAR Technical Report #298
Publication Date: 03/23/2015
Type: Literature Review
Abstract

Cassava production is prone to many constraints throughout the production cycle, including biotic, abiotic, and management constraints. This brief reviews the literature on the production impacts of two key cassava stressors: cassava bacterial blight (CBB) and postharvest physiological deterioration (PPD). We summarize available estimates of the frequency and magnitude of these constraints relative to other drivers of cassava production losses that affect smallholder farmers in Sub-Saharan Africa (SSA), review the control strategies proposed in the literature, report on the views of several experts in the field, and identify research gaps where relatively little appears to be known about CBB or PPD yield impacts or best practices for CBB or PPD management. 

EPAR Technical Report #295
Publication Date: 02/22/2015
Type: Literature Review
Abstract

This report reviews the literature on textural attributes of Root, Tuber, and Banana (RTB) crops with a focus on studies relevant for crop research and development in Sub-Saharan Africa. The texture of cooked root and tuber crops is often cited as a primary determinant of consumer acceptability of new varieties, including those produced through traditional breeding and through genetic engineering. Evidence from texture-related consumer preferences studies for the RTB crops tropical yam, sweetpotato, banana/plantain, cassava, and potato, as well as the results of physicochemical and genetic studies detailing the current scientific understanding of drivers of textural traits, is reviewed and synthesized.

EPAR Technical Report #207
Publication Date: 12/17/2012
Type: Literature Review
Abstract

This report provides a general overview of the markets for yams in Nigeria. The first section describes trends in yam production and consumption and international trade since 1990. The second section summarizes the varieties grown in Nigeria and their uses, followed by a discussion of the importance of yams as a source of nutrition and household income. The final section provides details about the production and marketing systems for yams in Nigeria, including environmental and gender considerations. Nigeria is the world’s largest yam producer in terms of quantity. Yam production and consumption have increased over the past twenty years, though more recently, production has been somewhat in decline and yields have been stagnant. The Nigerian government has played a more active role in improving agricultural production and export of root and tuber crops including yams in recent years, but so far with limited success. Yam producers and traders report diverse constraints to their full participation in the market, including high cost of inputs, planting materials and labor, lack of credit, limited access to proper, secure storage facilities, and high transportation costs.

EPAR Technical Report #211
Publication Date: 12/14/2012
Type: Literature Review
Abstract

This report provides a general overview of the sweet potato value chain in Tanzania. The first section describes trends in sweet potato production and consumption since 1990. The second section describes the uses and importance of sweet potatoes in Tanzania. The final section outlines current practices and constraints in production, post-production, and marketing. Tanzania ranks fifth in the world in quantity of sweet potatoes produced. Production and consumption of sweet potatoes have been relatively constant over the past 10 years, although both production and consumption in this period have been high in comparison to earlier decades. We find that sweet potato yields increased in the early 2000s, but have stagnated since, and are far short of potential yields. Sweet potato consumption is almost entirely domestic and plays an important role in nutrition and food security for smallholder farmers. Sweet potato production faces a variety of constraints, including pests and disease, short shelf life, lack of planting materials, damage during handling, and lack of market access.

EPAR Technical Report #220
Publication Date: 12/14/2012
Type: Literature Review
Abstract

This report provides a general overview of the markets for sweet potatoes in Nigeria. The first section describes trends in sweet potato production and consumption and international trade since 1990. The second section summarizes the varieties grown in Nigeria and their uses, followed by a discussion of the importance of sweet potatoes for food security and as a source of nutrition and household income. The following section reviews and presents details about the production and marketing systems for sweet potatoes in Nigeria, including environmental and gender considerations. 

EPAR Technical Report #206
Publication Date: 12/12/2012
Type: Literature Review
Abstract

This report provides a general overview of the market for yams in Ghana. We begin by describing historical trends in yam production and consumption since 1996, recent international trade, and prices. The second section summarizes the varieties grown in Ghana and their uses. The next several sections review available information about the production and marketing systems, followed by a discussion of the importance of yams as a source of nutrition and household income. The limited information available on sweet potato production in Ghana is presented in the appendix. We find that yam production in Ghana has increased steadily over the last 15 years, and that while yam yields have increased from 12.8 MT/Ha in 1996 to 15.6 MT/Ha in 2011, an estimated yield gap of 33.4 MT/Ha persists. Yam export levels have varied over the past 15 years, but show a generally positive trend. Most yam farmers are male smallholders with low levels of education, while most retailers, wholesalers and cross-border traders are women.

EPAR Technical Report #223
Publication Date: 12/10/2012
Type: Literature Review
Abstract

Cassava is a tuber crop originating in South America and grown in tropical and subtropical areas throughout the world. Cassava use varies significantly by region. In Africa, cassava is primarily grown for food. In Asia, production is typically for industrial purposes, including ethanol, while in Latin America and the Caribbean it is commonly used in animal feed. Both roots and leaves are consumed, though most information on production focuses on roots. There are bitter and sweet varieties; bitter cassava has a high cyanide content and must be processed prior to consumption, while sweet varieties can be eaten directly. This report presents information about current production, constraints, and future potential of cassava. We discuss cassava’s importance in Africa, current worldwide production, projections for supply and demand, production constraints, and current policies affecting cassava production and trade. We include global information but focus on Africa, particularly Nigeria, Ghana, Uganda, and Tanzania.