Theodore Asiimwe

• Fellow at Rwanda Agriculture Board

Maize lethal necrosis (MLN) is emergent in East Africa, first reported in 2011 in Kenya, and is devastating to maize production in the region. MLN is caused by co‐infection of maize with the emergent maize chlorotic mottle virus (MCMV) and any of several maize‐infecting potyviruses endemic in East Africa and worldwide. Here, we examine the distribu...

ASSESSMENT OF MAIZE LETHAL NECROSIS (MLN) PREVALENCE AND ITS IMPACT ON MAIZE PRODUCTION IN RWANDA By Theodore Asiimwe, Leonidas Dusengemungu, Antoine Nyirigira, Felix Gatunzi, Immaculee Nishimwe, Jeanne d’Arc Uwimana, Jovia Kamatenesi, Claver Ngaboyisonga, Patrick Karangwa Abstract Maize lethal necrosis (MLN) is a serious viral disease of maize,...

Since 2011–2012, Maize lethal necrosis (MLN) has emerged in East Africa, causing massive yield loss and propelling research to identify viruses and virus populations present in maize. As expected, next generation sequencing (NGS) has revealed diverse and abundant viruses from the family Potyviridae, primarily sugarcane mosaic virus (SCMV), and maiz...

Background: The early generation selection of cassava quantitative and qualitative traits saves breeding resources as it can shorten breeding schemes. The inheritance analysis provides important breeding information for developing new improved varieties. This study aimed at developing an F1 segregating cassava population and determining mode of ge...

Genetic diversity is essential for crop improvement and knowledge of the genetic variability within a breeding population facilitates its future exploitation. This study examined the phenotypic and genetic variability for specific cassava key traits in a collection of 30 genotypes at five environments in Rwanda. Seventy-three percent of the variati...

Maize lethal necrosis (MLN), a severe virus disease of maize, has emerged in East Africa in recent years with devastating effects on production and food security where maize is a staple subsistence crop. In extensive surveys of MLN-symptomatic plants in East Africa, sequences of Johnsongrass mosaic virus (JGMV) were identified in Uganda, Kenya, Rwa...

General and specific environmental adaptation of genotypes is the main goal of breeders. However, genotype-by-environment (G × E) interaction complicates the identification of genotypes for release. This study aimed at analyzing the effects of G × E interaction on the expression of important cassava traits using two multivariate analyses: additive...

The genetic diversity available in sweetpotato has not been explored to develop dual-purpose sweetpotato varieties (DPSVs). The objectives of this study were to assess the level of phenotypic diversity present among sweetpotato varieties grown in Rwanda, and to select suitable parents for breeding DPSVs. Fifty-one diverse sweetpotato genotypes were...

The present poster highlighted the following objectives: Assessed the roles of sweetpotato in the crop-livestock farming systems in Rwanda Identified farmer-preferred traits and their implications in breeding dual-purpose sweetpotato varieties in Rwanda

Physiological postharvest deterioration (PPD) and late bulking are among the traits that make cassava an unattractive crop in many environments. This study aimed at assessing the main constraints of cassava production, the effects of late bulking, the losses due to PPD and the factors affecting adoption of new cultivars in Rwanda. A participatory r...

Physiological postharvest deterioration (PPD) of cassava is the main constraint affecting its nutritional and economical values. PPD is induced by wounds when detaching storage roots from mother plant during harvesting. It is accelerated by the reactive oxygen species (ROS) such as oxygen ion (O2) and peroxide (O2)-2. The carotenoid content and its...

Explants of two elite cooking banana cultivars, FHIA17 and INJAGI were collected from healthy source of stock plants growing in the field. Sterilization was evaluated using different concentrations (20, 30, 40, 50 and 60%) of a commercial bleach (JIK) for 25 min. Effects of cytokinins benzyl amino purine (BAP), 2-isopentenyl adenine (2iP) and kinet...

Fungus-derived indole-3-acetic acid (IAA), which is involved in ectomycorrhizal development, affects both partners. The biosynthesis pathway, excretion from fungal hyphae, the induction of branching in fungal cultures and enhanced Hartig' net formation in mycorrhiza were shown. Gene expression studies, incorporation of labeled compounds into IAA, h...

Agricultural research is the engine driving agricultural growth in Rwanda which has resulted in the country being food secure over the last two years (2010–2011). Research has developed and released high yielding, disease and pest resistant crop varieties, animal breeds/genotypes and other improved technologies. These have resulted in increased pro...

The current study aimed at evaluating the effect of gibberellic acid (GA 3) and sucrose on in vitro propagation of two elite sweet potato cultivars (Ukerewe and Gihingamukungu). Nodal explants from in vitro growing plantlets were harvested and cultured on Murashige and Skoog media supplemented with 2.5, 5, 10, 20 and 40 μM, GA 3 . In a separate exp...

Limited access to high quality planting material is a major factor constraining productivity of pyrethrum in Rwanda. The objective of this study was to develop an efficient protocol for regeneration and mass propagation of high yielding and high pyrethrin content pyrethrum cultivars using tissue culture techniques. Nodal explants from in vitro grow...

About 200 Million people in the world suffer from hunger. The United Nations (2007) estimates that the world population will reach 8.1 Billion people by 2030. Meeting global food requirements will necessitate increasing food production by 50%. The most attractive strategy to meet this challenge is to increase smallholder agricultural productivity....

About 200 Million people in the world suffer from hunger. The United Nations (2007) estimates that the world population will reach 8.1 Billion people by 2030. Meeting global food requirements will necessitate increasing food production by 50%. The most attractive strategy to meet this challenge is to increase smallholder agricultural productivity....

Bamboo is one of the fastest growing and highest yielding renewable natural resources with multiple uses in the world. It is used to make furniture, charcoal, food, control soil erosion and can assist in carbon sequestration. The increasing rate of tropical deforestation calls for search for alternative natural resources and the characteristics of...

Bamboo is one of the fastest growing and highest yielding renewable natural resources with multiple uses in the world. It is used to make furniture, charcoal, food, control soil erosion and can assist in carbon sequestration. The increasing rate of tropical deforestation calls for search for alternative natural resources and the characteristics of...

An outbreak of a respiratory disease in cattle was reported in February 2010 at the Rwanda Agriculture Board research station at Nyagatare in Eastern Rwanda. The tentative diagnosis based on clinical and postmortem signs suggested infection with Contagious Bovine Pleuropneumonia (CBPP). This paper presents a comparison of diagnostic techniques and...

We report the first mycorrhizal fungal aldehyde dehydrogenase gene, ald1, which was isolated from the basidiomycete Tricholoma vaccinum. The gene, encoding a protein Ald1 of 502 amino acids, is up-regulated in ectomycorrhiza. Phylogenetic analyses using 53 specific fungal aldehyde dehydrogenases from all major phyla in the kingdom of fungi includin...

Cassava (Manihot esculenta) belongs to the Euphorbiaceae family and has about 100 species. In Rwanda, it plays a key role as food security and income generating crop. It is described as " classic food security crop " because it offers the advantage of a harvest even in situations of erratic rainfall and infertile soils. Cassava is a major staple fo...

Cyphomandra betacea (Cav.) is commonly known as tamarillo or tree tomato. This species is mainly used for its edible fruits which have a high nutritional value and contain relatively high amounts of vitamins B6, C, E and provitamin A. The cultivation of tamarillo in Rwanda is facing major challenges caused mainly by viral diseases like tamarillo mo...

Cassava (Manihot esculenta) belongs to the Euphorbiaceae family and has about 100 species. In Rwanda, it plays a key role as food security and income generating crop. It is described as " classic food security crop " because it offers the advantage of a harvest even in situations of erratic rainfall and infertile soils. Cassava is a major staple fo...

Pseudomonas strains have shown promising results in biological control of late blight caused by Phytophthora infestans. However, the mechanism(s) and metabolites involved are in many cases poorly understood. Here, the role of the cyclic lipopeptide massetolide A of Pseudomonas fluorescens SS101 in biocontrol of tomato late blight was examined. Pseu...

Water hyacinth (Eichhornia crassipes) was officially recognized as having invaded the world's second largest lake, East Africa's Lake Victoria in the late 1980's. Since then various management activities have been implemented by the governments of Kenya, Tanzania, and Uganda, with support from a variety international partners, to review, evaluate a...

Understanding of ectomycorrhiza functioning has been slowed down by less investigations of this symbiotic association at the molecular level. In this study, the possible role of a specific fungal aldehyde dehydrogenase (ALDH) in the host-specific mutual symbiosis between the basidiomycete fungus Tricholoma vaccinum and its compatible host plant spr...